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  • Use Extension method to write cleaner code

    - by Fredrik N
    This blog post will show you step by step to refactoring some code to be more readable (at least what I think). Patrik Löwnedahl gave me some of the ideas when we where talking about making code much cleaner. The following is an simple application that will have a list of movies (Normal and Transfer). The task of the application is to calculate the total sum of each movie and also display the price of each movie. class Program { enum MovieType { Normal, Transfer } static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies) { if (movie == MovieType.Normal) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } else if (movie == MovieType.Transfer) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } } } private static IEnumerable<MovieType> GetMovies() { return new List<MovieType>() { MovieType.Normal, MovieType.Transfer, MovieType.Normal }; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } In the code above I’m using an enum, a good way to add types (isn’t it ;)). I also use one foreach loop to calculate the price, the loop has a condition statement to check what kind of movie is added to the list of movies. I want to reuse the foreach only to increase performance and let it do two things (isn’t that smart of me?! ;)). First of all I can admit, I’m not a big fan of enum. Enum often results in ugly condition statements and can be hard to maintain (if a new type is added we need to check all the code in our app to see if we use the enum somewhere else). I don’t often care about pre-optimizations when it comes to write code (of course I have performance in mind). I rather prefer to use two foreach to let them do one things instead of two. So based on what I don’t like and Martin Fowler’s Refactoring catalog, I’m going to refactoring this code to what I will call a more elegant and cleaner code. First of all I’m going to use Split Loop to make sure the foreach will do one thing not two, it will results in two foreach (Don’t care about performance here, if the results will results in bad performance, you can refactoring later, but computers are so fast to day, so iterating through a list is not often so time consuming.) Note: The foreach actually do four things, will come to is later. var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies) { if (movie == MovieType.Normal) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } } foreach (var movie in movies) { if (movie == MovieType.Transfer) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To remove the condition statement we can use the Where extension method added to the IEnumerable<T> and is located in the System.Linq namespace: foreach (var movie in movies.Where( m => m == MovieType.Normal)) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } foreach (var movie in movies.Where( m => m == MovieType.Transfer)) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The above code will still do two things, calculate the total price, and display the price of the movie. I will not take care of it at the moment, instead I will focus on the enum and try to remove them. One way to remove enum is by using the Replace Conditional with Polymorphism. So I will create two classes, one base class called Movie, and one called MovieTransfer. The Movie class will have a property called Price, the Movie will now hold the price:   public class Movie { public virtual int Price { get { return 2; } } } public class MovieTransfer : Movie { public override int Price { get { return 3; } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The following code has no enum and will use the new Movie classes instead: class Program { static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies.Where( m => m is Movie)) { totalPriceOfNormalMovie += movie.Price; Console.WriteLine(movie.Price); } foreach (var movie in movies.Where( m => m is MovieTransfer)) { totalPriceOfTransferMovie += movie.Price; Console.WriteLine(movie.Price); } } private static IEnumerable<Movie> GetMovies() { return new List<Movie>() { new Movie(), new MovieTransfer(), new Movie() }; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   If you take a look at the foreach now, you can see it still actually do two things, calculate the price and display the price. We can do some more refactoring here by using the Sum extension method to calculate the total price of the movies:   static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = movies.Where(m => m is Movie) .Sum(m => m.Price); int totalPriceOfTransferMovie = movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); foreach (var movie in movies.Where( m => m is Movie)) Console.WriteLine(movie.Price); foreach (var movie in movies.Where( m => m is MovieTransfer)) Console.WriteLine(movie.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now when the Movie object will hold the price, there is no need to use two separate foreach to display the price of the movies in the list, so we can use only one instead: foreach (var movie in movies) Console.WriteLine(movie.Price); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If we want to increase the Maintainability index we can use the Extract Method to move the Sum of the prices into two separate methods. The name of the method will explain what we are doing: static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); foreach (var movie in movies) Console.WriteLine(movie.Price); } private static int TotalPriceOfMovieTransfer(IEnumerable<Movie> movies) { return movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); } private static int TotalPriceOfMovie(IEnumerable<Movie> movies) { return movies.Where(m => m is Movie) .Sum(m => m.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now to the last thing, I love the ForEach method of the List<T>, but the IEnumerable<T> doesn’t have it, so I created my own ForEach extension, here is the code of the ForEach extension method: public static class LoopExtensions { public static void ForEach<T>(this IEnumerable<T> values, Action<T> action) { Contract.Requires(values != null); Contract.Requires(action != null); foreach (var v in values) action(v); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I will now replace the foreach by using this ForEach method: static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); movies.ForEach(m => Console.WriteLine(m.Price)); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The ForEach on the movies will now display the price of the movie, but maybe we want to display the name of the movie etc, so we can use Extract Method by moving the lamdba expression into a method instead, and let the method explains what we are displaying: movies.ForEach(DisplayMovieInfo); private static void DisplayMovieInfo(Movie movie) { Console.WriteLine(movie.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now the refactoring is done! Here is the complete code:   class Program { static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); movies.ForEach(DisplayMovieInfo); } private static void DisplayMovieInfo(Movie movie) { Console.WriteLine(movie.Price); } private static int TotalPriceOfMovieTransfer(IEnumerable<Movie> movies) { return movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); } private static int TotalPriceOfMovie(IEnumerable<Movie> movies) { return movies.Where(m => m is Movie) .Sum(m => m.Price); } private static IEnumerable<Movie> GetMovies() { return new List<Movie>() { new Movie(), new MovieTransfer(), new Movie() }; } } public class Movie { public virtual int Price { get { return 2; } } } public class MovieTransfer : Movie { public override int Price { get { return 3; } } } pulbic static class LoopExtensions { public static void ForEach<T>(this IEnumerable<T> values, Action<T> action) { Contract.Requires(values != null); Contract.Requires(action != null); foreach (var v in values) action(v); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I think the new code is much cleaner than the first one, and I love the ForEach extension on the IEnumerable<T>, I can use it for different kind of things, for example: movies.Where(m => m is Movie) .ForEach(DoSomething); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } By using the Where and ForEach extension method, some if statements can be removed and will make the code much cleaner. But the beauty is in the eye of the beholder. What would you have done different, what do you think will make the first example in the blog post look much cleaner than my results, comments are welcome! If you want to know when I will publish a new blog post, you can follow me on twitter: http://www.twitter.com/fredrikn

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  • ASP.NET Frameworks and Raw Throughput Performance

    - by Rick Strahl
    A few days ago I had a curious thought: With all these different technologies that the ASP.NET stack has to offer, what's the most efficient technology overall to return data for a server request? When I started this it was mere curiosity rather than a real practical need or result. Different tools are used for different problems and so performance differences are to be expected. But still I was curious to see how the various technologies performed relative to each just for raw throughput of the request getting to the endpoint and back out to the client with as little processing in the actual endpoint logic as possible (aka Hello World!). I want to clarify that this is merely an informal test for my own curiosity and I'm sharing the results and process here because I thought it was interesting. It's been a long while since I've done any sort of perf testing on ASP.NET, mainly because I've not had extremely heavy load requirements and because overall ASP.NET performs very well even for fairly high loads so that often it's not that critical to test load performance. This post is not meant to make a point  or even come to a conclusion which tech is better, but just to act as a reference to help understand some of the differences in perf and give a starting point to play around with this yourself. I've included the code for this simple project, so you can play with it and maybe add a few additional tests for different things if you like. Source Code on GitHub I looked at this data for these technologies: ASP.NET Web API ASP.NET MVC WebForms ASP.NET WebPages ASMX AJAX Services  (couldn't get AJAX/JSON to run on IIS8 ) WCF Rest Raw ASP.NET HttpHandlers It's quite a mixed bag, of course and the technologies target different types of development. What started out as mere curiosity turned into a bit of a head scratcher as the results were sometimes surprising. What I describe here is more to satisfy my curiosity more than anything and I thought it interesting enough to discuss on the blog :-) First test: Raw Throughput The first thing I did is test raw throughput for the various technologies. This is the least practical test of course since you're unlikely to ever create the equivalent of a 'Hello World' request in a real life application. The idea here is to measure how much time a 'NOP' request takes to return data to the client. So for this request I create the simplest Hello World request that I could come up for each tech. Http Handler The first is the lowest level approach which is an HTTP handler. public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public bool IsReusable { get { return true; } } } WebForms Next I added a couple of ASPX pages - one using CodeBehind and one using only a markup page. The CodeBehind page simple does this in CodeBehind without any markup in the ASPX page: public partial class HelloWorld_CodeBehind : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Response.Write("Hello World. Time is: " + DateTime.Now.ToString() ); Response.End(); } } while the Markup page only contains some static output via an expression:<%@ Page Language="C#" AutoEventWireup="false" CodeBehind="HelloWorld_Markup.aspx.cs" Inherits="AspNetFrameworksPerformance.HelloWorld_Markup" %> Hello World. Time is <%= DateTime.Now %> ASP.NET WebPages WebPages is the freestanding Razor implementation of ASP.NET. Here's the simple HelloWorld.cshtml page:Hello World @DateTime.Now WCF REST WCF REST was the token REST implementation for ASP.NET before WebAPI and the inbetween step from ASP.NET AJAX. I'd like to forget that this technology was ever considered for production use, but I'll include it here. Here's an OperationContract class: [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World" + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } } WCF REST can return arbitrary results by returning a Stream object and a content type. The code above turns the string result into a stream and returns that back to the client. ASP.NET AJAX (ASMX Services) I also wanted to test ASP.NET AJAX services because prior to WebAPI this is probably still the most widely used AJAX technology for the ASP.NET stack today. Unfortunately I was completely unable to get this running on my Windows 8 machine. Visual Studio 2012  removed adding of ASP.NET AJAX services, and when I tried to manually add the service and configure the script handler references it simply did not work - I always got a SOAP response for GET and POST operations. No matter what I tried I always ended up getting XML results even when explicitly adding the ScriptHandler. So, I didn't test this (but the code is there - you might be able to test this on a Windows 7 box). ASP.NET MVC Next up is probably the most popular ASP.NET technology at the moment: MVC. Here's the small controller: public class MvcPerformanceController : Controller { public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } } ASP.NET WebAPI Next up is WebAPI which looks kind of similar to MVC. Except here I have to use a StringContent result to return the response: public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } } Testing Take a minute to think about each of the technologies… and take a guess which you think is most efficient in raw throughput. The fastest should be pretty obvious, but the others - maybe not so much. The testing I did is pretty informal since it was mainly to satisfy my curiosity - here's how I did this: I used Apache Bench (ab.exe) from a full Apache HTTP installation to run and log the test results of hitting the server. ab.exe is a small executable that lets you hit a URL repeatedly and provides counter information about the number of requests, requests per second etc. ab.exe and the batch file are located in the \LoadTests folder of the project. An ab.exe command line  looks like this: ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld which hits the specified URL 100,000 times with a load factor of 20 concurrent requests. This results in output like this:   It's a great way to get a quick and dirty performance summary. Run it a few times to make sure there's not a large amount of varience. You might also want to do an IISRESET to clear the Web Server. Just make sure you do a short test run to warm up the server first - otherwise your first run is likely to be skewed downwards. ab.exe also allows you to specify headers and provide POST data and many other things if you want to get a little more fancy. Here all tests are GET requests to keep it simple. I ran each test: 100,000 iterations Load factor of 20 concurrent connections IISReset before starting A short warm up run for API and MVC to make sure startup cost is mitigated Here is the batch file I used for the test: IISRESET REM make sure you add REM C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin REM to your path so ab.exe can be found REM Warm up ab.exe -n100 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJsonab.exe -n100 -c20 http://localhost/aspnetperf/api/HelloWorldJson ab.exe -n100 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld ab.exe -n100000 -c20 http://localhost/aspnetperf/handler.ashx > handler.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_CodeBehind.aspx > AspxCodeBehind.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_Markup.aspx > AspxMarkup.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld > Wcf.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldCode > Mvc.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld > WebApi.txt I ran each of these tests 3 times and took the average score for Requests/second, with the machine otherwise idle. I did see a bit of variance when running many tests but the values used here are the medians. Part of this has to do with the fact I ran the tests on my local machine - result would probably more consistent running the load test on a separate machine hitting across the network. I ran these tests locally on my laptop which is a Dell XPS with quad core Sandibridge I7-2720QM @ 2.20ghz and a fast SSD drive on Windows 8. CPU load during tests ran to about 70% max across all 4 cores (IOW, it wasn't overloading the machine). Ideally you can try running these tests on a separate machine hitting the local machine. If I remember correctly IIS 7 and 8 on client OSs don't throttle so the performance here should be Results Ok, let's cut straight to the chase. Below are the results from the tests… It's not surprising that the handler was fastest. But it was a bit surprising to me that the next fastest was WebForms and especially Web Forms with markup over a CodeBehind page. WebPages also fared fairly well. MVC and WebAPI are a little slower and the slowest by far is WCF REST (which again I find surprising). As mentioned at the start the raw throughput tests are not overly practical as they don't test scripting performance for the HTML generation engines or serialization performances of the data engines. All it really does is give you an idea of the raw throughput for the technology from time of request to reaching the endpoint and returning minimal text data back to the client which indicates full round trip performance. But it's still interesting to see that Web Forms performs better in throughput than either MVC, WebAPI or WebPages. It'd be interesting to try this with a few pages that actually have some parsing logic on it, but that's beyond the scope of this throughput test. But what's also amazing about this test is the sheer amount of traffic that a laptop computer is handling. Even the slowest tech managed 5700 requests a second, which is one hell of a lot of requests if you extrapolate that out over a 24 hour period. Remember these are not static pages, but dynamic requests that are being served. Another test - JSON Data Service Results The second test I used a JSON result from several of the technologies. I didn't bother running WebForms and WebPages through this test since that doesn't make a ton of sense to return data from the them (OTOH, returning text from the APIs didn't make a ton of sense either :-) In these tests I have a small Person class that gets serialized and then returned to the client. The Person class looks like this: public class Person { public Person() { Id = 10; Name = "Rick"; Entered = DateTime.Now; } public int Id { get; set; } public string Name { get; set; } public DateTime Entered { get; set; } } Here are the updated handler classes that use Person: Handler public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { var action = context.Request.QueryString["action"]; if (action == "json") JsonRequest(context); else TextRequest(context); } public void TextRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public void JsonRequest(HttpContext context) { var json = JsonConvert.SerializeObject(new Person(), Formatting.None); context.Response.ContentType = "application/json"; context.Response.Write(json); } public bool IsReusable { get { return true; } } } This code adds a little logic to check for a action query string and route the request to an optional JSON result method. To generate JSON, I'm using the same JSON.NET serializer (JsonConvert.SerializeObject) used in Web API to create the JSON response. WCF REST   [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World " + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } [OperationContract] [WebGet(ResponseFormat=WebMessageFormat.Json,BodyStyle=WebMessageBodyStyle.WrappedRequest)] public Person HelloWorldJson() { // Add your operation implementation here return new Person(); } } For WCF REST all I have to do is add a method with the Person result type.   ASP.NET MVC public class MvcPerformanceController : Controller { // // GET: /MvcPerformance/ public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } public JsonResult HelloWorldJson() { return Json(new Person(), JsonRequestBehavior.AllowGet); } } For MVC all I have to do for a JSON response is return a JSON result. ASP.NET internally uses JavaScriptSerializer. ASP.NET WebAPI public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } [HttpGet] public Person HelloWorldJson() { return new Person(); } [HttpGet] public HttpResponseMessage HelloWorldJson2() { var response = new HttpResponseMessage(HttpStatusCode.OK); response.Content = new ObjectContent<Person>(new Person(), GlobalConfiguration.Configuration.Formatters.JsonFormatter); return response; } } Testing and Results To run these data requests I used the following ab.exe commands:REM JSON RESPONSES ab.exe -n100000 -c20 http://localhost/aspnetperf/Handler.ashx?action=json > HandlerJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJson > MvcJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorldJson > WebApiJson.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorldJson > WcfJson.txt The results from this test run are a bit interesting in that the WebAPI test improved performance significantly over returning plain string content. Here are the results:   The performance for each technology drops a little bit except for WebAPI which is up quite a bit! From this test it appears that WebAPI is actually significantly better performing returning a JSON response, rather than a plain string response. Snag with Apache Benchmark and 'Length Failures' I ran into a little snag with Apache Benchmark, which was reporting failures for my Web API requests when serializing. As the graph shows performance improved significantly from with JSON results from 5580 to 6530 or so which is a 15% improvement (while all others slowed down by 3-8%). However, I was skeptical at first because the WebAPI test reports showed a bunch of errors on about 10% of the requests. Check out this report: Notice the Failed Request count. What the hey? Is WebAPI failing on roughly 10% of requests when sending JSON? Turns out: No it's not! But it took some sleuthing to figure out why it reports these failures. At first I thought that Web API was failing, and so to make sure I re-ran the test with Fiddler attached and runiisning the ab.exe test by using the -X switch: ab.exe -n100 -c10 -X localhost:8888 http://localhost/aspnetperf/api/HelloWorldJson which showed that indeed all requests where returning proper HTTP 200 results with full content. However ab.exe was reporting the errors. After some closer inspection it turned out that the dates varying in size altered the response length in dynamic output. For example: these two results: {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.841926-10:00"} {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.8519262-10:00"} are different in length for the number which results in 68 and 69 bytes respectively. The same URL produces different result lengths which is what ab.exe reports. I didn't notice at first bit the same is happening when running the ASHX handler with JSON.NET result since it uses the same serializer that varies the milliseconds. Moral: You can typically ignore Length failures in Apache Benchmark and when in doubt check the actual output with Fiddler. Note that the other failure values are accurate though. Another interesting Side Note: Perf drops over Time As I was running these tests repeatedly I was finding that performance steadily dropped from a startup peak to a 10-15% lower stable level. IOW, with Web API I'd start out with around 6500 req/sec and in subsequent runs it keeps dropping until it would stabalize somewhere around 5900 req/sec occasionally jumping lower. For these tests this is why I did the IIS RESET and warm up for individual tests. This is a little puzzling. Looking at Process Monitor while the test are running memory very quickly levels out as do handles and threads, on the first test run. Subsequent runs everything stays stable, but the performance starts going downwards. This applies to all the technologies - Handlers, Web Forms, MVC, Web API - curious to see if others test this and see similar results. Doing an IISRESET then resets everything and performance starts off at peak again… Summary As I stated at the outset, these were informal to satiate my curiosity not to prove that any technology is better or even faster than another. While there clearly are differences in performance the differences (other than WCF REST which was by far the slowest and the raw handler which was by far the highest) are relatively minor, so there is no need to feel that any one technology is a runaway standout in raw performance. Choosing a technology is about more than pure performance but also about the adequateness for the job and the easy of implementation. The strengths of each technology will make for any minor performance difference we see in these tests. However, to me it's important to get an occasional reality check and compare where new technologies are heading. Often times old stuff that's been optimized and designed for a time of less horse power can utterly blow the doors off newer tech and simple checks like this let you compare. Luckily we're seeing that much of the new stuff performs well even in V1.0 which is great. To me it was very interesting to see Web API perform relatively badly with plain string content, which originally led me to think that Web API might not be properly optimized just yet. For those that caught my Tweets late last week regarding WebAPI's slow responses was with String content which is in fact considerably slower. Luckily where it counts with serialized JSON and XML WebAPI actually performs better. But I do wonder what would make generic string content slower than serialized code? This stresses another point: Don't take a single test as the final gospel and don't extrapolate out from a single set of tests. Certainly Twitter can make you feel like a fool when you post something immediate that hasn't been fleshed out a little more <blush>. Egg on my face. As a result I ended up screwing around with this for a few hours today to compare different scenarios. Well worth the time… I hope you found this useful, if not for the results, maybe for the process of quickly testing a few requests for performance and charting out a comparison. Now onwards with more serious stuff… Resources Source Code on GitHub Apache HTTP Server Project (ab.exe is part of the binary distribution)© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Grandparent – Parent – Child Reports in SQL Developer

    - by thatjeffsmith
    You’ll never see one of these family stickers on my car, but I promise not to judge…much. Parent – Child reports are pretty straightforward in Oracle SQL Developer. You have a ‘parent’ report, and then one or more ‘child’ reports which are based off of a value in a selected row or value from the parent. If you need a quick tutorial to get up to speed on the subject, go ahead and take 5 minutes Shortly before I left for vacation 2 weeks agao, I got an interesting question from one of my Twitter Followers: @thatjeffsmith any luck with the #Oracle awr reports in #SQLDeveloper?This is easy with multi generation parent>child Done in #dbvisualizer — Ronald Rood (@Ik_zelf) August 26, 2012 Now that I’m back from vacation, I can tell Ronald and everyone else that the answer is ‘Yes!’ And here’s how Time to Get Out Your XML Editor Don’t have one? That’s OK, SQL Developer can edit XML files. While the Reporting interface doesn’t surface the ability to create multi-generational reports, the underlying code definitely supports it. We just need to hack away at the XML that powers a report. For this example I’m going to start simple. A query that brings back DEPARTMENTs, then EMPLOYEES, then JOBs. We can build the first two parts of the report using the report editor. A Parent-Child report in Oracle SQL Developer (Departments – Employees) Save the Report to XML Once you’ve generated the XML file, open it with your favorite XML editor. For this example I’ll be using the build-it XML editor in SQL Developer. SQL Developer Reports in their raw XML glory! Right after the PDF element in the XML document, we can start a new ‘child’ report by inserting a DISPLAY element. I just copied and pasted the existing ‘display’ down so I wouldn’t have to worry about screwing anything up. Note I also needed to change the ‘master’ name so it wouldn’t confuse SQL Developer when I try to import/open a report that has the same name. Also I needed to update the binds tags to reflect the names from the child versus the original parent report. This is pretty easy to figure out on your own actually – I mean I’m no real developer and I got it pretty quick. <?xml version="1.0" encoding="UTF-8" ?> <displays> <display id="92857fce-0139-1000-8006-7f0000015340" type="" style="Table" enable="true"> <name><![CDATA[Grandparent]]></name> <description><![CDATA[]]></description> <tooltip><![CDATA[]]></tooltip> <drillclass><![CDATA[null]]></drillclass> <CustomValues> <TYPE>horizontal</TYPE> </CustomValues> <query> <sql><![CDATA[select * from hr.departments]]></sql> </query> <pdf version="VERSION_1_7" compression="CONTENT"> <docproperty title="" author="" subject="" keywords="" /> <cell toppadding="2" bottompadding="2" leftpadding="2" rightpadding="2" horizontalalign="LEFT" verticalalign="TOP" wrap="true" /> <column> <heading font="Courier" size="10" style="NORMAL" color="-16777216" rowshading="-1" labeling="FIRST_PAGE" /> <footing font="Courier" size="10" style="NORMAL" color="-16777216" rowshading="-1" labeling="NONE" /> <blob blob="NONE" zip="false" /> </column> <table font="Courier" size="10" style="NORMAL" color="-16777216" userowshading="false" oddrowshading="-1" evenrowshading="-1" showborders="true" spacingbefore="12" spacingafter="12" horizontalalign="LEFT" /> <header enable="false" generatedate="false"> <data> null </data> </header> <footer enable="false" generatedate="false"> <data value="null" /> </footer> <security enable="false" useopenpassword="false" openpassword="" encryption="EXCLUDE_METADATA"> <permission enable="false" permissionpassword="" allowcopying="true" allowprinting="true" allowupdating="false" allowaccessdevices="true" /> </security> <pagesetup papersize="LETTER" orientation="1" measurement="in" margintop="1.0" marginbottom="1.0" marginleft="1.0" marginright="1.0" /> </pdf> <display id="null" type="" style="Table" enable="true"> <name><![CDATA[Parent]]></name> <description><![CDATA[]]></description> <tooltip><![CDATA[]]></tooltip> <drillclass><![CDATA[null]]></drillclass> <CustomValues> <TYPE>horizontal</TYPE> </CustomValues> <query> <sql><![CDATA[select * from hr.employees where department_id = EPARTMENT_ID]]></sql> <binds> <bind id="DEPARTMENT_ID"> <prompt><![CDATA[DEPARTMENT_ID]]></prompt> <tooltip><![CDATA[DEPARTMENT_ID]]></tooltip> <value><![CDATA[NULL_VALUE]]></value> </bind> </binds> </query> <pdf version="VERSION_1_7" compression="CONTENT"> <docproperty title="" author="" subject="" keywords="" /> <cell toppadding="2" bottompadding="2" leftpadding="2" rightpadding="2" horizontalalign="LEFT" verticalalign="TOP" wrap="true" /> <column> <heading font="Courier" size="10" style="NORMAL" color="-16777216" rowshading="-1" labeling="FIRST_PAGE" /> <footing font="Courier" size="10" style="NORMAL" color="-16777216" rowshading="-1" labeling="NONE" /> <blob blob="NONE" zip="false" /> </column> <table font="Courier" size="10" style="NORMAL" color="-16777216" userowshading="false" oddrowshading="-1" evenrowshading="-1" showborders="true" spacingbefore="12" spacingafter="12" horizontalalign="LEFT" /> <header enable="false" generatedate="false"> <data> null </data> </header> <footer enable="false" generatedate="false"> <data value="null" /> </footer> <security enable="false" useopenpassword="false" openpassword="" encryption="EXCLUDE_METADATA"> <permission enable="false" permissionpassword="" allowcopying="true" allowprinting="true" allowupdating="false" allowaccessdevices="true" /> </security> <pagesetup papersize="LETTER" orientation="1" measurement="in" margintop="1.0" marginbottom="1.0" marginleft="1.0" marginright="1.0" /> </pdf> <display id="null" type="" style="Table" enable="true"> <name><![CDATA[Child]]></name> <description><![CDATA[]]></description> <tooltip><![CDATA[]]></tooltip> <drillclass><![CDATA[null]]></drillclass> <CustomValues> <TYPE>horizontal</TYPE> </CustomValues> <query> <sql><![CDATA[select * from hr.jobs where job_id = :JOB_ID]]></sql> <binds> <bind id="JOB_ID"> <prompt><![CDATA[JOB_ID]]></prompt> <tooltip><![CDATA[JOB_ID]]></tooltip> <value><![CDATA[NULL_VALUE]]></value> </bind> </binds> </query> <pdf version="VERSION_1_7" compression="CONTENT"> <docproperty title="" author="" subject="" keywords="" /> <cell toppadding="2" bottompadding="2" leftpadding="2" rightpadding="2" horizontalalign="LEFT" verticalalign="TOP" wrap="true" /> <column> <heading font="Courier" size="10" style="NORMAL" color="-16777216" rowshading="-1" labeling="FIRST_PAGE" /> <footing font="Courier" size="10" style="NORMAL" color="-16777216" rowshading="-1" labeling="NONE" /> <blob blob="NONE" zip="false" /> </column> <table font="Courier" size="10" style="NORMAL" color="-16777216" userowshading="false" oddrowshading="-1" evenrowshading="-1" showborders="true" spacingbefore="12" spacingafter="12" horizontalalign="LEFT" /> <header enable="false" generatedate="false"> <data> null </data> </header> <footer enable="false" generatedate="false"> <data value="null" /> </footer> <security enable="false" useopenpassword="false" openpassword="" encryption="EXCLUDE_METADATA"> <permission enable="false" permissionpassword="" allowcopying="true" allowprinting="true" allowupdating="false" allowaccessdevices="true" /> </security> <pagesetup papersize="LETTER" orientation="1" measurement="in" margintop="1.0" marginbottom="1.0" marginleft="1.0" marginright="1.0" /> </pdf> </display> </display> </display> </displays> Save the file and ‘Open Report…’ You’ll see your new report name in the tree. You just need to double-click it to open it. Here’s what it looks like running A 3 generation family Now Let’s Build an AWR Text Report Ronald wanted to have the ability to query AWR snapshots and generate the AWR reports. That requires a few inputs, including a START and STOP snapshot ID. That basically tells AWR what time period to use for generating the report. And here’s where it gets tricky. We’ll need to use aliases for the SNAP_ID column. Since we’re using the same column name from 2 different queries, we need to use different bind variables. Fortunately for us, SQL Developer’s clever enough to use the column alias as the BIND. Here’s what I mean: Grandparent Query SELECT snap_id start1, begin_interval_time, end_interval_time FROM dba_hist_snapshot ORDER BY 1 asc Parent Query SELECT snap_id stop1, begin_interval_time, end_interval_time, :START1 carry FROM dba_hist_snapshot WHERE snap_id > :START1 ORDER BY 1 asc And here’s where it gets even trickier – you can’t reference a bind from outside the parent query. My grandchild report can’t reference a value from the grandparent report. So I just carry the selected value down to the parent. In my parent query SELECT you see the ‘:START1′ at the end? That’s making that value available to me when I use it in my grandchild query. To complicate things a bit further, I can’t have a column name with a ‘:’ in it, or SQL Developer will get confused when I try to reference the value of the variable with the ‘:’ – and ‘::Name’ doesn’t work. But that’s OK, just alias it. Grandchild Query Select Output From Table(Dbms_Workload_Repository.Awr_Report_Text(1298953802, 1,:CARRY, :STOP1)); Ok, and the last trick – I hard-coded my report to use my database’s DB_ID and INST_ID into the AWR package call. Now a smart person could figure out a way to make that work on any database, but I got lazy and and ran out of time. But this should be far enough for you to take it from here. Here’s what my report looks like now: Caution: don’t run this if you haven’t licensed Enterprise Edition with Diagnostic Pack. The Raw XML for this AWR Report <?xml version="1.0" encoding="UTF-8" ?> <displays> <display id="927ba96c-0139-1000-8001-7f0000015340" type="" style="Table" enable="true"> <name><![CDATA[AWR Start Stop Report Final]]></name> <description><![CDATA[]]></description> <tooltip><![CDATA[]]></tooltip> <drillclass><![CDATA[null]]></drillclass> <CustomValues> <TYPE>horizontal</TYPE> </CustomValues> <query> <sql><![CDATA[SELECT snap_id start1, begin_interval_time, end_interval_time FROM dba_hist_snapshot ORDER BY 1 asc]]></sql> </query> <display id="null" type="" style="Table" enable="true"> <name><![CDATA[Stop SNAP_ID]]></name> <description><![CDATA[]]></description> <tooltip><![CDATA[]]></tooltip> <drillclass><![CDATA[null]]></drillclass> <CustomValues> <TYPE>horizontal</TYPE> </CustomValues> <query> <sql><![CDATA[SELECT snap_id stop1, begin_interval_time, end_interval_time, :START1 carry FROM dba_hist_snapshot WHERE snap_id > :START1 ORDER BY 1 asc]]></sql> </query> <display id="null" type="" style="Table" enable="true"> <name><![CDATA[AWR Report]]></name> <description><![CDATA[]]></description> <tooltip><![CDATA[]]></tooltip> <drillclass><![CDATA[null]]></drillclass> <CustomValues> <TYPE>horizontal</TYPE> </CustomValues> <query> <sql><![CDATA[Select Output From Table(Dbms_Workload_Repository.Awr_Report_Text(1298953802, 1,:CARRY, :STOP1 ))]]></sql> </query> </display> </display> </display> </displays> Should We Build Support for Multiple Levels of Reports into the User Interface? Let us know! A comment here or a suggestion on our SQL Developer Exchange might help your case!

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  • Developing Spring Portlet for use inside Weblogic Portal / Webcenter Portal

    - by Murali Veligeti
    We need to understand the main difference between portlet workflow and servlet workflow.The main difference between portlet workflow and servlet workflow is that, the request to the portlet can have two distinct phases: 1) Action phase 2) Render phase. The Action phase is executed only once and is where any 'backend' changes or actions occur, such as making changes in a database. The Render phase then produces what is displayed to the user each time the display is refreshed. The critical point here is that for a single overall request, the action phase is executed only once, but the render phase may be executed multiple times. This provides a clean separation between the activities that modify the persistent state of your system and the activities that generate what is displayed to the user.The dual phases of portlet requests are one of the real strengths of the JSR-168 specification. For example, dynamic search results can be updated routinely on the display without the user explicitly re-running the search. Most other portlet MVC frameworks attempt to completely hide the two phases from the developer and make it look as much like traditional servlet development as possible - we think this approach removes one of the main benefits of using portlets. So, the separation of the two phases is preserved throughout the Spring Portlet MVC framework. The primary manifestation of this approach is that where the servlet version of the MVC classes will have one method that deals with the request, the portlet version of the MVC classes will have two methods that deal with the request: one for the action phase and one for the render phase. For example, where the servlet version of AbstractController has the handleRequestInternal(..) method, the portlet version of AbstractController has handleActionRequestInternal(..) and handleRenderRequestInternal(..) methods.The Spring Portlet Framework is designed around a DispatcherPortlet that dispatches requests to handlers, with configurable handler mappings and view resolution, just as the DispatcherServlet in the Spring Web Framework does.  Developing portlet.xml Let's start the sample development by creating the portlet.xml file in the /WebContent/WEB-INF/ folder as shown below: <?xml version="1.0" encoding="UTF-8"?> <portlet-app version="2.0" xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <portlet> <portlet-name>SpringPortletName</portlet-name> <portlet-class>org.springframework.web.portlet.DispatcherPortlet</portlet-class> <supports> <mime-type>text/html</mime-type> <portlet-mode>view</portlet-mode> </supports> <portlet-info> <title>SpringPortlet</title> </portlet-info> </portlet> </portlet-app> DispatcherPortlet is responsible for handling every client request. When it receives a request, it finds out which Controller class should be used for handling this request, and then it calls its handleActionRequest() or handleRenderRequest() method based on the request processing phase. The Controller class executes business logic and returns a View name that should be used for rendering markup to the user. The DispatcherPortlet then forwards control to that View for actual markup generation. As you can see, DispatcherPortlet is the central dispatcher for use within Spring Portlet MVC Framework. Note that your portlet application can define more than one DispatcherPortlet. If it does so, then each of these portlets operates its own namespace, loading its application context and handler mapping. The DispatcherPortlet is also responsible for loading application context (Spring configuration file) for this portlet. First, it tries to check the value of the configLocation portlet initialization parameter. If that parameter is not specified, it takes the portlet name (that is, the value of the <portlet-name> element), appends "-portlet.xml" to it, and tries to load that file from the /WEB-INF folder. In the portlet.xml file, we did not specify the configLocation initialization parameter, so let's create SpringPortletName-portlet.xml file in the next section. Developing SpringPortletName-portlet.xml Create the SpringPortletName-portlet.xml file in the /WebContent/WEB-INF folder of your application as shown below: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd"> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/jsp/"/> <property name="suffix" value=".jsp"/> </bean> <bean id="pointManager" class="com.wlp.spring.bo.internal.PointManagerImpl"> <property name="users"> <list> <ref bean="point1"/> <ref bean="point2"/> <ref bean="point3"/> <ref bean="point4"/> </list> </property> </bean> <bean id="point1" class="com.wlp.spring.bean.User"> <property name="name" value="Murali"/> <property name="points" value="6"/> </bean> <bean id="point2" class="com.wlp.spring.bean.User"> <property name="name" value="Sai"/> <property name="points" value="13"/> </bean> <bean id="point3" class="com.wlp.spring.bean.User"> <property name="name" value="Rama"/> <property name="points" value="43"/> </bean> <bean id="point4" class="com.wlp.spring.bean.User"> <property name="name" value="Krishna"/> <property name="points" value="23"/> </bean> <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"> <property name="basename" value="messages"/> </bean> <bean name="/users.htm" id="userController" class="com.wlp.spring.controller.UserController"> <property name="pointManager" ref="pointManager"/> </bean> <bean name="/pointincrease.htm" id="pointIncreaseController" class="com.wlp.spring.controller.IncreasePointsFormController"> <property name="sessionForm" value="true"/> <property name="pointManager" ref="pointManager"/> <property name="commandName" value="pointIncrease"/> <property name="commandClass" value="com.wlp.spring.bean.PointIncrease"/> <property name="formView" value="pointincrease"/> <property name="successView" value="users"/> </bean> <bean id="parameterMappingInterceptor" class="org.springframework.web.portlet.handler.ParameterMappingInterceptor" /> <bean id="portletModeParameterHandlerMapping" class="org.springframework.web.portlet.handler.PortletModeParameterHandlerMapping"> <property name="order" value="1" /> <property name="interceptors"> <list> <ref bean="parameterMappingInterceptor" /> </list> </property> <property name="portletModeParameterMap"> <map> <entry key="view"> <map> <entry key="pointincrease"> <ref bean="pointIncreaseController" /> </entry> <entry key="users"> <ref bean="userController" /> </entry> </map> </entry> </map> </property> </bean> <bean id="portletModeHandlerMapping" class="org.springframework.web.portlet.handler.PortletModeHandlerMapping"> <property name="order" value="2" /> <property name="portletModeMap"> <map> <entry key="view"> <ref bean="userController" /> </entry> </map> </property> </bean> </beans> The SpringPortletName-portlet.xml file is an application context file for your MVC portlet. It has a couple of bean definitions: viewController. At this point, remember that the viewController bean definition points to the com.ibm.developerworks.springmvc.ViewController.java class. portletModeHandlerMapping. As we discussed in the last section, whenever DispatcherPortlet gets a client request, it tries to find a suitable Controller class for handling that request. That is where PortletModeHandlerMapping comes into the picture. The PortletModeHandlerMapping class is a simple implementation of the HandlerMapping interface and is used by DispatcherPortlet to find a suitable Controller for every request. The PortletModeHandlerMapping class uses Portlet mode for the current request to find a suitable Controller class to use for handling the request. The portletModeMap property of portletModeHandlerMapping bean is the place where we map the Portlet mode name against the Controller class. In the sample code, we show that viewController is responsible for handling View mode requests. Developing UserController.java In the preceding section, you learned that the viewController bean is responsible for handling all the View mode requests. Your next step is to create the UserController.java class as shown below: public class UserController extends AbstractController { private PointManager pointManager; public void handleActionRequest(ActionRequest request, ActionResponse response) throws Exception { } public ModelAndView handleRenderRequest(RenderRequest request, RenderResponse response) throws ServletException, IOException { String now = (new java.util.Date()).toString(); Map<String, Object> myModel = new HashMap<String, Object>(); myModel.put("now", now); myModel.put("users", this.pointManager.getUsers()); return new ModelAndView("users", "model", myModel); } public void setPointManager(PointManager pointManager) { this.pointManager = pointManager; } } Every controller class in Spring Portlet MVC Framework must implement the org.springframework.web. portlet.mvc.Controller interface directly or indirectly. To make things easier, Spring Framework provides AbstractController class, which is the default implementation of the Controller interface. As a developer, you should always extend your controller from either AbstractController or one of its more specific subclasses. Any implementation of the Controller class should be reusable, thread-safe, and capable of handling multiple requests throughout the lifecycle of the portlet. In the sample code, we create the ViewController class by extending it from AbstractController. Because we don't want to do any action processing in the HelloSpringPortletMVC portlet, we override only the handleRenderRequest() method of AbstractController. Now, the only thing that HelloWorldPortletMVC should do is render the markup of View.jsp to the user when it receives a user request to do so. To do that, return the object of ModelAndView with a value of view equal to View. Developing web.xml According to Portlet Specification 1.0, every portlet application is also a Servlet Specification 2.3-compliant Web application, and it needs a Web application deployment descriptor (that is, web.xml). Let’s create the web.xml file in the /WEB-INF/ folder as shown in listing 4. Follow these steps: Open the existing web.xml file located at /WebContent/WEB-INF/web.xml. Replace the contents of this file with the code as shown below: <servlet> <servlet-name>ViewRendererServlet</servlet-name> <servlet-class>org.springframework.web.servlet.ViewRendererServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ViewRendererServlet</servlet-name> <url-pattern>/WEB-INF/servlet/view</url-pattern> </servlet-mapping> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> The web.xml file for the sample portlet declares two things: ViewRendererServlet. The ViewRendererServlet is the bridge servlet for portlet support. During the render phase, DispatcherPortlet wraps PortletRequest into ServletRequest and forwards control to ViewRendererServlet for actual rendering. This process allows Spring Portlet MVC Framework to use the same View infrastructure as that of its servlet version, that is, Spring Web MVC Framework. ContextLoaderListener. The ContextLoaderListener class takes care of loading Web application context at the time of the Web application startup. The Web application context is shared by all the portlets in the portlet application. In case of duplicate bean definition, the bean definition in the portlet application context takes precedence over the Web application context. The ContextLoader class tries to read the value of the contextConfigLocation Web context parameter to find out the location of the context file. If the contextConfigLocation parameter is not set, then it uses the default value, which is /WEB-INF/applicationContext.xml, to load the context file. The Portlet Controller interface requires two methods that handle the two phases of a portlet request: the action request and the render request. The action phase should be capable of handling an action request and the render phase should be capable of handling a render request and returning an appropriate model and view. While the Controller interface is quite abstract, Spring Portlet MVC offers a lot of controllers that already contain a lot of the functionality you might need – most of these are very similar to controllers from Spring Web MVC. The Controller interface just defines the most common functionality required of every controller - handling an action request, handling a render request, and returning a model and a view. How rendering works As you know, when the user tries to access a page with PointSystemPortletMVC portlet on it or when the user performs some action on any other portlet on that page or tries to refresh that page, a render request is sent to the PointSystemPortletMVC portlet. In the sample code, because DispatcherPortlet is the main portlet class, Weblogic Portal / Webcenter Portal calls its render() method and then the following sequence of events occurs: The render() method of DispatcherPortlet calls the doDispatch() method, which in turn calls the doRender() method. After the doRenderService() method gets control, first it tries to find out the locale of the request by calling the PortletRequest.getLocale() method. This locale is used while making all the locale-related decisions for choices such as which resource bundle should be loaded or which JSP should be displayed to the user based on the locale. After that, the doRenderService() method starts iterating through all the HandlerMapping classes configured for this portlet, calling their getHandler() method to identify the appropriate Controller for handling this request. In the sample code, we have configured only PortletModeHandlerMapping as a HandlerMapping class. The PortletModeHandlerMapping class reads the value of the current portlet mode, and based on that, it finds out, the Controller class that should be used to handle this request. In the sample code, ViewController is configured to handle the View mode request so that the PortletModeHandlerMapping class returns the object of ViewController. After the object of ViewController is returned, the doRenderService() method calls its handleRenderRequestInternal() method. Implementation of the handleRenderRequestInternal() method in ViewController.java is very simple. It logs a message saying that it got control, and then it creates an instance of ModelAndView with a value equal to View and returns it to DispatcherPortlet. After control returns to doRenderService(), the next task is to figure out how to render View. For that, DispatcherPortlet starts iterating through all the ViewResolvers configured in your portlet application, calling their resolveViewName() method. In the sample code we have configured only one ViewResolver, InternalResourceViewResolver. When its resolveViewName() method is called with viewName, it tries to add /WEB-INF/jsp as a prefix to the view name and to add JSP as a suffix. And it checks if /WEB-INF/jsp/View.jsp exists. If it does exist, it returns the object of JstlView wrapping View.jsp. After control is returned to the doRenderService() method, it creates the object PortletRequestDispatcher, which points to /WEB-INF/servlet/view – that is, ViewRendererServlet. Then it sets the object of JstlView in the request and dispatches the request to ViewRendererServlet. After ViewRendererServlet gets control, it reads the JstlView object from the request attribute and creates another RequestDispatcher pointing to the /WEB-INF/jsp/View.jsp URL and passes control to it for actual markup generation. The markup generated by View.jsp is returned to user. At this point, you may question the need for ViewRendererServlet. Why can't DispatcherPortlet directly forward control to View.jsp? Adding ViewRendererServlet in between allows Spring Portlet MVC Framework to reuse the existing View infrastructure. You may appreciate this more when we discuss how easy it is to integrate Apache Tiles Framework with your Spring Portlet MVC Framework. The attached project SpringPortlet.zip should be used to import the project in to your OEPE Workspace. SpringPortlet_Jars.zip contains jar files required for the application. Project is written on Spring 2.5.  The same JSR 168 portlet should work on Webcenter Portal as well.  Downloads: Download WeblogicPotal Project which consists of Spring Portlet. Download Spring Jars In-addition to above you need to download Spring.jar (Spring2.5)

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  • Metro: Creating an IndexedDbDataSource for WinJS

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can create custom data sources which you can use with the controls in the WinJS library. In particular, I explain how you can create an IndexedDbDataSource which you can use to store and retrieve data from an IndexedDB database. If you want to skip ahead, and ignore all of the fascinating content in-between, I’ve included the complete code for the IndexedDbDataSource at the very bottom of this blog entry. What is IndexedDB? IndexedDB is a database in the browser. You can use the IndexedDB API with all modern browsers including Firefox, Chrome, and Internet Explorer 10. And, of course, you can use IndexedDB with Metro style apps written with JavaScript. If you need to persist data in a Metro style app written with JavaScript then IndexedDB is a good option. Each Metro app can only interact with its own IndexedDB databases. And, IndexedDB provides you with transactions, indices, and cursors – the elements of any modern database. An IndexedDB database might be different than the type of database that you normally use. An IndexedDB database is an object-oriented database and not a relational database. Instead of storing data in tables, you store data in object stores. You store JavaScript objects in an IndexedDB object store. You create new IndexedDB object stores by handling the upgradeneeded event when you attempt to open a connection to an IndexedDB database. For example, here’s how you would both open a connection to an existing database named TasksDB and create the TasksDB database when it does not already exist: var reqOpen = window.indexedDB.open(“TasksDB”, 2); reqOpen.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); }; reqOpen.onsuccess = function () { var db = reqOpen.result; // Do something with db }; When you call window.indexedDB.open(), and the database does not already exist, then the upgradeneeded event is raised. In the code above, the upgradeneeded handler creates a new object store named tasks. The new object store has an auto-increment column named id which acts as the primary key column. If the database already exists with the right version, and you call window.indexedDB.open(), then the success event is raised. At that point, you have an open connection to the existing database and you can start doing something with the database. You use asynchronous methods to interact with an IndexedDB database. For example, the following code illustrates how you would add a new object to the tasks object store: var transaction = db.transaction(“tasks”, “readwrite”); var reqAdd = transaction.objectStore(“tasks”).add({ name: “Feed the dog” }); reqAdd.onsuccess = function() { // Tasks added successfully }; The code above creates a new database transaction, adds a new task to the tasks object store, and handles the success event. If the new task gets added successfully then the success event is raised. Creating a WinJS IndexedDbDataSource The most powerful control in the WinJS library is the ListView control. This is the control that you use to display a collection of items. If you want to display data with a ListView control, you need to bind the control to a data source. The WinJS library includes two objects which you can use as a data source: the List object and the StorageDataSource object. The List object enables you to represent a JavaScript array as a data source and the StorageDataSource enables you to represent the file system as a data source. If you want to bind an IndexedDB database to a ListView then you have a choice. You can either dump the items from the IndexedDB database into a List object or you can create a custom data source. I explored the first approach in a previous blog entry. In this blog entry, I explain how you can create a custom IndexedDB data source. Implementing the IListDataSource Interface You create a custom data source by implementing the IListDataSource interface. This interface contains the contract for the methods which the ListView needs to interact with a data source. The easiest way to implement the IListDataSource interface is to derive a new object from the base VirtualizedDataSource object. The VirtualizedDataSource object requires a data adapter which implements the IListDataAdapter interface. Yes, because of the number of objects involved, this is a little confusing. Your code ends up looking something like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); The code above is used to create a new class named IndexedDbDataSource which derives from the base VirtualizedDataSource class. In the constructor for the new class, the base class _baseDataSourceConstructor() method is called. A data adapter is passed to the _baseDataSourceConstructor() method. The code above creates a new method exposed by the IndexedDbDataSource named nuke(). The nuke() method deletes all of the objects from an object store. The code above also overrides a method named remove(). Our derived remove() method accepts any type of key and removes the matching item from the object store. Almost all of the work of creating a custom data source goes into building the data adapter class. The data adapter class implements the IListDataAdapter interface which contains the following methods: · change() · getCount() · insertAfter() · insertAtEnd() · insertAtStart() · insertBefore() · itemsFromDescription() · itemsFromEnd() · itemsFromIndex() · itemsFromKey() · itemsFromStart() · itemSignature() · moveAfter() · moveBefore() · moveToEnd() · moveToStart() · remove() · setNotificationHandler() · compareByIdentity Fortunately, you are not required to implement all of these methods. You only need to implement the methods that you actually need. In the case of the IndexedDbDataSource, I implemented the getCount(), itemsFromIndex(), insertAtEnd(), and remove() methods. If you are creating a read-only data source then you really only need to implement the getCount() and itemsFromIndex() methods. Implementing the getCount() Method The getCount() method returns the total number of items from the data source. So, if you are storing 10,000 items in an object store then this method would return the value 10,000. Here’s how I implemented the getCount() method: getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); } The first thing that you should notice is that the getCount() method returns a WinJS promise. This is a requirement. The getCount() method is asynchronous which is a good thing because all of the IndexedDB methods (at least the methods implemented in current browsers) are also asynchronous. The code above retrieves an object store and then uses the IndexedDB count() method to get a count of the items in the object store. The value is returned from the promise by calling complete(). Implementing the itemsFromIndex method When a ListView displays its items, it calls the itemsFromIndex() method. By default, it calls this method multiple times to get different ranges of items. Three parameters are passed to the itemsFromIndex() method: the requestIndex, countBefore, and countAfter parameters. The requestIndex indicates the index of the item from the database to show. The countBefore and countAfter parameters represent hints. These are integer values which represent the number of items before and after the requestIndex to retrieve. Again, these are only hints and you can return as many items before and after the request index as you please. Here’s how I implemented the itemsFromIndex method: itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); } In the code above, a cursor is used to iterate through the objects in an object store. You fetch the next item in the cursor by calling either the cursor.continue() or cursor.advance() method. The continue() method moves forward by one object and the advance() method moves forward a specified number of objects. Each time you call continue() or advance(), the success event is raised again. If the cursor is null then you know that you have reached the end of the cursor and you can return the results. Some things to be careful about here. First, the return value from the itemsFromIndex() method must implement the IFetchResult interface. In particular, you must return an object which has an items, offset, and totalCount property. Second, each item in the items array must implement the IListItem interface. Each item should have a key and a data property. Implementing the insertAtEnd() Method When creating the IndexedDbDataSource, I wanted to go beyond creating a simple read-only data source and support inserting and deleting objects. If you want to support adding new items with your data source then you need to implement the insertAtEnd() method. Here’s how I implemented the insertAtEnd() method for the IndexedDbDataSource: insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); } When implementing the insertAtEnd() method, you need to be careful to return an object which implements the IItem interface. In particular, you should return an object that has a key and a data property. The key must be a string and it uniquely represents the new item added to the data source. The value of the data property represents the new item itself. Implementing the remove() Method Finally, you use the remove() method to remove an item from the data source. You call the remove() method with the key of the item which you want to remove. Implementing the remove() method in the case of the IndexedDbDataSource was a little tricky. The problem is that an IndexedDB object store uses an integer key and the VirtualizedDataSource requires a string key. For that reason, I needed to override the remove() method in the derived IndexedDbDataSource class like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); When you call remove(), you end up calling a method of the IndexedDbDataAdapter named removeInternal() . Here’s what the removeInternal() method looks like: setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); } The removeInternal() method calls the IndexedDB delete() method to delete an item from the object store. If the item is deleted successfully then the _notificationHandler.remove() method is called. Because we are not implementing the standard IListDataAdapter remove() method, we need to notify the data source (and the ListView control bound to the data source) that an item has been removed. The way that you notify the data source is by calling the _notificationHandler.remove() method. Notice that we get the _notificationHandler in the code above by implementing another method in the IListDataAdapter interface: the setNotificationHandler() method. You can raise the following types of notifications using the _notificationHandler: · beginNotifications() · changed() · endNotifications() · inserted() · invalidateAll() · moved() · removed() · reload() These methods are all part of the IListDataNotificationHandler interface in the WinJS library. Implementing the nuke() Method I wanted to implement a method which would remove all of the items from an object store. Therefore, I created a method named nuke() which calls the IndexedDB clear() method: nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); } Notice that the nuke() method calls the _notificationHandler.reload() method to notify the ListView to reload all of the items from its data source. Because we are implementing a custom method here, we need to use the _notificationHandler to send an update. Using the IndexedDbDataSource To illustrate how you can use the IndexedDbDataSource, I created a simple task list app. You can add new tasks, delete existing tasks, and nuke all of the tasks. You delete an item by selecting an item (swipe or right-click) and clicking the Delete button. Here’s the HTML page which contains the ListView, the form for adding new tasks, and the buttons for deleting and nuking tasks: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>DataSources</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.1.0.RC/css/ui-dark.css" rel="stylesheet" /> <script src="//Microsoft.WinJS.1.0.RC/js/base.js"></script> <script src="//Microsoft.WinJS.1.0.RC/js/ui.js"></script> <!-- DataSources references --> <link href="indexedDb.css" rel="stylesheet" /> <script type="text/javascript" src="indexedDbDataSource.js"></script> <script src="indexedDb.js"></script> </head> <body> <div id="tmplTask" data-win-control="WinJS.Binding.Template"> <div class="taskItem"> Id: <span data-win-bind="innerText:id"></span> <br /><br /> Name: <span data-win-bind="innerText:name"></span> </div> </div> <div id="lvTasks" data-win-control="WinJS.UI.ListView" data-win-options="{ itemTemplate: select('#tmplTask'), selectionMode: 'single' }"></div> <form id="frmAdd"> <fieldset> <legend>Add Task</legend> <label>New Task</label> <input id="inputTaskName" required /> <button>Add</button> </fieldset> </form> <button id="btnNuke">Nuke</button> <button id="btnDelete">Delete</button> </body> </html> And here is the JavaScript code for the TaskList app: /// <reference path="//Microsoft.WinJS.1.0.RC/js/base.js" /> /// <reference path="//Microsoft.WinJS.1.0.RC/js/ui.js" /> function init() { WinJS.UI.processAll().done(function () { var lvTasks = document.getElementById("lvTasks").winControl; // Bind the ListView to its data source var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; // Wire-up Add, Delete, Nuke buttons document.getElementById("frmAdd").addEventListener("submit", function (evt) { evt.preventDefault(); tasksDataSource.beginEdits(); tasksDataSource.insertAtEnd(null, { name: document.getElementById("inputTaskName").value }).done(function (newItem) { tasksDataSource.endEdits(); document.getElementById("frmAdd").reset(); lvTasks.ensureVisible(newItem.index); }); }); document.getElementById("btnDelete").addEventListener("click", function () { if (lvTasks.selection.count() == 1) { lvTasks.selection.getItems().done(function (items) { tasksDataSource.remove(items[0].data.id); }); } }); document.getElementById("btnNuke").addEventListener("click", function () { tasksDataSource.nuke(); }); // This method is called to initialize the IndexedDb database function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } }); } document.addEventListener("DOMContentLoaded", init); The IndexedDbDataSource is created and bound to the ListView control with the following two lines of code: var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; The IndexedDbDataSource is created with four parameters: the name of the database to create, the version of the database to create, the name of the object store to create, and a function which contains code to initialize the new database. The upgrade function creates a new object store named tasks with an auto-increment property named id: function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } The Complete Code for the IndexedDbDataSource Here’s the complete code for the IndexedDbDataSource: (function () { /************************************************ * The IndexedDBDataAdapter enables you to work * with a HTML5 IndexedDB database. *************************************************/ var IndexedDbDataAdapter = WinJS.Class.define( function (dbName, dbVersion, objectStoreName, upgrade, error) { this._dbName = dbName; // database name this._dbVersion = dbVersion; // database version this._objectStoreName = objectStoreName; // object store name this._upgrade = upgrade; // database upgrade script this._error = error || function (evt) { console.log(evt.message); }; }, { /******************************************* * IListDataAdapter Interface Methods ********************************************/ getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); }, itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); }, insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); }, setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, /***************************************** * IndexedDbDataSource Method ******************************************/ removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); }, nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); }, /******************************************* * Private Methods ********************************************/ _ensureDbOpen: function () { var that = this; // Try to get cached Db if (that._cachedDb) { return WinJS.Promise.wrap(that._cachedDb); } // Otherwise, open the database return new WinJS.Promise(function (complete, error, progress) { var reqOpen = window.indexedDB.open(that._dbName, that._dbVersion); reqOpen.onerror = function (evt) { error(); }; reqOpen.onupgradeneeded = function (evt) { that._upgrade(evt); that._notificationHandler.invalidateAll(); }; reqOpen.onsuccess = function () { that._cachedDb = reqOpen.result; complete(that._cachedDb); }; }); }, _getObjectStore: function (type) { type = type || "readonly"; var that = this; return new WinJS.Promise(function (complete, error) { that._ensureDbOpen().then(function (db) { var transaction = db.transaction(that._objectStoreName, type); complete(transaction.objectStore(that._objectStoreName)); }); }); }, _get: function (key) { return new WinJS.Promise(function (complete, error) { that._getObjectStore().done(function (store) { var reqGet = store.get(key); reqGet.onerror = that._error; reqGet.onsuccess = function (item) { complete(item); }; }); }); } } ); var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); WinJS.Namespace.define("DataSources", { IndexedDbDataSource: IndexedDbDataSource }); })(); Summary In this blog post, I provided an overview of how you can create a new data source which you can use with the WinJS library. I described how you can create an IndexedDbDataSource which you can use to bind a ListView control to an IndexedDB database. While describing how you can create a custom data source, I explained how you can implement the IListDataAdapter interface. You also learned how to raise notifications — such as a removed or invalidateAll notification — by taking advantage of the methods of the IListDataNotificationHandler interface.

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  • Building applications with WCF - Intro

    - by skjagini
    I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database     BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had  to derive from EF specific base classes. In EF 4 it  is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks.  Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System;   namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } }   In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity;   namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } }   Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information.   using System; using System.Data.Entity.ModelConfiguration;   namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); }   private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id);   //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } }   Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context.   We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository   using System; using System.Data.Entity; using System.Linq; using BankDAL.Model;   namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers;   public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; }   public IQueryable<Customer> Query() { return _customers; }   public void Add(Customer customer) { _customers.Add(customer); } } }   From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods.   Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model;   namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts;   public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; }   public IQueryable<CheckingAccount> Query() { return _checkingAccounts; }   public void Add(CheckingAccount account) { _checkingAccounts.Add(account); }   public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); }   } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details.   using System; using System.ServiceModel; using BankDAL.Model;   namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth);   [OperationContract] Customer GetCustomer(int id);   } }   ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account.   using System.ServiceModel;   namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId);   [OperationContract] void DepositAmount(int customerId,decimal amount);   [OperationContract] void WithdrawAmount(int customerId, decimal amount);   } }   Services   Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services.   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract;   namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth };   using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; }   public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); }   } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract;   namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault();   if (account != null) return account.Balance;   return null; } }   public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault();   if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); }   account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted");   bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } }   BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients.   using System;   namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); }   private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); }   private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open();   if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient    The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files.   <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/>   </client> </system.serviceModel> The client uses a façade to connect to the services   using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract;   namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); }   public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); }   public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); }   } }   With that in place, lets get our unit tests going   using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract;   namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); }   private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); }     [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); }   [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id));   // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id));   // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id));   // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); }   [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss");   var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id;   ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId));   try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); }   Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } }   We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account.  Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling.  Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

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  • CodePlex Daily Summary for Saturday, October 29, 2011

    CodePlex Daily Summary for Saturday, October 29, 2011Popular Releasespatterns & practices: Enterprise Library Contrib: Enterprise Library Contrib - 5.0 (Oct 2011): This release of Enterprise Library Contrib is based on the Microsoft patterns & practices Enterprise Library 5.0 core and contains the following: Common extensionsTypeConfigurationElement<T> - A Polymorphic Configuration Element without having to be part of a PolymorphicConfigurationElementCollection. AnonymousConfigurationElement - A Configuration element that can be uniquely identified without having to define its name explicitly. Data Access Application Block extensionsMySql Provider - ...Network Monitor Open Source Parsers: Network Monitor Parsers 3.4.2748: The Network Monitor Parsers packages contain parsers for more than 400 network protocols, including RFC based public protocols and protocols for Microsoft products defined in the Microsoft Open Specifications for Windows and SQL Server. NetworkMonitor_Parsers.msi is the base parser package which defines parsers for commonly used public protocols and protocols for Microsoft Windows. In this release, NetowrkMonitor_Parsers.msi continues to improve quality and fix bugs. It has included the fo...Duckworth Lewis Professional Edition Calculator: DLcalc 3.0: DLcalc 3.0 can perform Duckworth/Lewis Professional Edition calculations 100% accurately. It also produces over-by-over and ball-by-ball PAR score tables.Folder Bookmarks: Folder Bookmarks 2.2.0.1: In this version: Custom Icons - now you can change the icons of the bookmarks. By default, whenever an image is added, the icon is automatically changed to a thumbnail of the picture. 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Fixed: Issue with partial thrust Cl...Free SharePoint Master Pages: Buried Alive (Halloween) Theme: Release Notes *Created for Halloween, you will find theme file, custom css file and images. *Created by Al Roome @AlstarRoome Features: Custom styling for web part Custom background *Screenshot https://s3.amazonaws.com/kkhipple/post/sharepoint-showcase-halloween.pngDevForce Application Framework: DevForce AF 2.0.3 RTW: PrerequisitesWPF 4.0 Silverlight 4.0 DevForce 2010 6.1.3.1 Download ContentsDebug and Release Assemblies API Documentation Source code License.txt Requirements.txt Release HighlightsNew: EventAggregator event forwarding New: EntityManagerInterceptor<T> to intercept EntityManger events New: IHarnessAware to allow for ViewModel setup when executed inside of the Development Harness New: Improved design time stability New: Support for add-in development New: CoroutineFns.To...NicAudio: NicAudio 2.0.5: Minor change to accept special DTS stereo modes (LtRt, AB,...)NDepend TFS 2010 integration: version 0.5.0 beta 1: Only the activity and the VS plugin are avalaible right now. They basically work. Data types that are logged into tfs reports are subject to change. This is no big deal since data is not yet sent into the warehouse.Windows Azure Toolkit for Windows Phone: Windows Azure Toolkit for Windows Phone v1.3.1: Upgraded Windows Azure projects to Windows Azure Tools for Microsoft Visual Studio 2010 1.5 – September 2011 Upgraded the tools tools to support the Windows Phone Developer Tools RTW Update SQL Azure only scenarios to use ASP.NET Universal Providers (through the System.Web.Providers v1.0.1 NuGet package) Changed Shared Access Signature service interface to support more operations Refactored Blobs API to have a similar interface and usage to that provided by the Windows Azure SDK Stor...DotNetNuke® FAQ: 05.00.00: FAQ (Frequently Asked Questions) 05.00.00 will work for any DNN version 5.6.1 and up. It is the first version which is rewritten in C#. The scope of this update is to fix all known issues and improve user interface. Please review and rate this release... (stars are welcome)BUG FIXESManage Categories button text was not localized Edit/Add FAQ Entry: button text was not localized ENHANCEMENTSAdded an option to select the control for category display: Listbox with checkboxes (flat category ...SiteMap Editor for Microsoft Dynamics CRM 2011: SiteMap Editor (1.0.921.340): Added CodePlex and PayPal links New iconNew ProjectsAsynk: Asynk is a framework/application that allows existing applications to easily be extended with an offloaded asynchronous worker layer. Asynk is developed using C#.Blob Tower Defense: 3D tower defense game for Windows Phone 7. School project for Brno University of Technology, computer graphics class.Booz: Booz is... An extended version of the boo shell (booish2 to be precise). Offers additional commands like cd, md, ls etc. I hope this shell can be used to take the position of/surpass the native windows shell in the near future.CIMS: a sanction infomation system for sencience and technology of hustCrystalDot - Icon Collection / Pack (LGPL): .Net / Mono freundliche Varainte der Crystal-Icons von Everaldo Icon collection / pack for .NET and Mono designed by Everaldo - KDE style http://www.everaldo.com/crystal/dotetes: dotetes adalah teka teki silang tool dikembangkan dengan bahasa c#Emoe': This Project is a Windows Phone 7.1 application.Equation Inversion: Visual Studion 2008 Add-in for equation inversions.Exploring VMR Features on WEC7: This is the sample application helps you to do alpha blending the bitmap on camera streaming in Windows Embedded Compact 7 using Directshow video Renderer (VMR). It is a VS2008 based smart device project developed on C++. I have explained the sample application in the following blog link. http://www.e-consystems.com/blog/windowsce/?p=759 EzValidation: Custom validation extensions for ASP.NET MVC 3. Includes server and client side model based validation attributes for: -- Equal To -- Not Equal To -- Greater Than -- Greater Than or Equal To -- Less Than -- Less Than or Equal To Supports validating against: -- Another Model Field -- A Specific Value -- Current Date/Yesterday/Tomorrow (for Dates and Strings) Download & Install via NuGet "package-install ezvalidation"Flu.net: Flu.net is a tool that helps you creating your own fluent syntax for .NET Framework applications in a declarative fashion. It is aimed for infrastructures and other open-source projects use.For Chess Endgames: King vs. King Opposition Calculator: You must input the locations of 2 kings on a chessboard, and whose turn it is to move. The calculator will display which king has the opposition, and how it can be used or maintained.GameTrakXNA: This project aims to create a simple library to use the unique GameTrak controller within XNA and Flash.Google Speech Recognition Example: Google Speech Recognition contains a working example of application that uses google speech recognition API. App contains all necessary dlls to record, decode and send your voice request to google service and recieve a text representation of what you've said. It's developed in C#Interval Mandelbrot Explorer: Explore the Mandelbrot set using interval arithmetic.ISD training tasks: ISD training examples and tasksiTunesControlBar: The iTunesControlBar helps user control their iTunes Application while it is minimized. iTunesControlBar resides at the top of the screen, invisible when not used, and allows playback and volume control, library searches and media information without the need to bring up iTunes.iTurtle: A bunch of Powerscripts to automate server management in AD environment.M26WC - Mono 2.6 Wizard Control: Wizard which runs under Mono2.6 A fork of: http://aerowizard.codeplex.com/Microsoft Help Viewer 2: Help Viewer 2 is the help runtime for both Visual Studio 11 help and Windows 8 help. The code in this project will help you use and understand the HV2 runtime API.MONTRASEC: Monitoring Trafficking in human beings and Sexual Exploitation of Children: benchmarking for member state and EU reporting, turning the SIAMSECT templates into a user-friendly interface and reporting tool. MTF.NET Runtime: Managed Task Framework .NET Runtime The MTF.NET runtime software and resulting assemblies are required to run applications built using the Managed Task Framework.NET Professional (Visual Studio 2010 extension) software design editor. The MTF.NET team are committed to continuously improving the core MTF.NET runtime and ensuring it is always available free and fully transparent. Pandoras Box: A greenfield inversion of control project utilising the power and flexibility of expressions and preferring convention over configuration.Pass the Puzzle: Pass the Puzzle is a frantic word-guessing party game. The game displays a few letters, and the players must come up with words containing those letters. But beware: if the timer goes off, you lose! It is based on the folk party game Pass the Parcel and is written in C#.PerCiGal: Percigal is a project for the development of applications for managing your personal media library. It consists in - a windows application to use at home to catalog movies, TV series, cast and books, with the support of the Internet for information retrieval; - a web interface for viewing and cataloging everywhere your media; - an application for smartphones. Project Flying Carpet: Este jogo é um projeto para a cadeira Projeto de Jogos: Motores Jogos do curso de Jogos Digitais da Unisinos.proxy browser: sed leo Latin's Butterfly....Python Multiple Dispatch: Multiple dispatch (AKA multimethods) for Python 3 via a metaclass and type annotations.reDune: ?????????? ???? ? ????? «????????? ? ???????? ???????». ???????? ?? Dune2000 ?? Westwood ? Electronic Arts.Rereadable: Keep page from internet for read it latter.ServStop: ServStop is a .NET application that makes it easy to stop several system services at once. Now you don't have to change startup types or stop them one at a time. It has a simple list-based interface with the ability to save and load lists of user services to stop. Written in C#.SharePoint 2010 Audience Membership Workflow Activity (Full Trust): A simple SharePoint 2010 workflow activity / workflow condition to check whether the user initiating the workflow is a member of a specified audience. Farm-level .wsp solution, written in C#. Once installed, the workflow activity can be used in SharePoint Designer 2010 declarative workflows.SQL Server® to Firebird DB converter: Converts Microsoft SQL Server® database into Firebird database including entire structure and datastegitest: test projectSystem.Threading.Joins: The Joins project provides asynchronous concurrency semantics based on join calculus and modeled after the Microsoft Research C? (C Omega) project.TestAndroidGame: try dev a TestAndroidGametetribricks: block game Topographic Explorer: A project to import, convert, explore, manipulate, and save topographical maps. Looking to use C# and WPF.Trading: Under construction!!!Trombone: Trombone makes it easier for Windows Mobile Professional users to automate status reply through SMS. It's developed in Visual C# 2008.Tulsa SharePoint Interest Group: Repository for source code for the Tulsa SharePoint Interest Group's web site. The Tulsa SharePoint Interest Group is using the Community Kit for SharePoint. This project will house any modifications that are specific to our user group.World of Tanks RU tiny stats collection utilty.: Tiny utility to load players stats for World of Tanks RU server. Results saved to comma separated file.WS-Discovery Proxy: Attempt at creating general purpose WS-Discovery Proxy.Yamaha Tu?n Tr?c: This application is used to manage information for Yamaha Tu?n Tr?c

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • CodePlex Daily Summary for Tuesday, November 22, 2011

    CodePlex Daily Summary for Tuesday, November 22, 2011Popular ReleasesDeveloper Team Article System Management: DTASM v1.3: ?? ??? ???? 3 ????? ???? ???? ????? ??? : - ????? ?????? ????? ???? ?? ??? ???? ????? ?? ??? ? ?? ???? ?????? ???? ?? ???? ????? ?? . - ??? ?? ???? ????? ???? ????? ???? ???? ?? ????? , ?????? ????? ????? ?? ??? . - ??? ??????? ??? ??? ???? ?? ????? ????? ????? .VideoLan DotNet for WinForm, WPF & Silverlight 5: VideoLan DotNet for WinForm, WPF, SL5 - 2011.11.22: The new version contains Silverlight 5 library: Vlc.DotNet.Silverlight. A sample could be tested here The new version add and correct many features : Correction : Reinitialize some variables Deprecate : Logging API, since VLC 1.2 (08/20/2011) Add subitem in LocationMedia (for Youtube videos, ...) Update Wpf sample to use Youtube videos Many others correctionsSharePoint 2010 FBA Pack: SharePoint 2010 FBA Pack 1.2.0: Web parts are now fully customizable via html templates (Issue #323) FBA Pack is now completely localizable using resource files. Thank you David Chen for submitting the code as well as Chinese translations of the FBA Pack! The membership request web part now gives the option of having the user enter the password and removing the captcha (Issue # 447) The FBA Pack will now work in a zone that does not have FBA enabled (Another zone must have FBA enabled, and the zone must contain the me...SharePoint 2010 Education Demo Project: Release SharePoint SP1 for Education Solutions: This release includes updates to the Content Packs for SharePoint SP1. All Content Packs have been updated to install successfully under SharePoint SP1SQL Monitor - tracking sql server activities: SQLMon 4.1 alpha 6: 1. improved support for schema 2. added find reference when right click on object list 3. added object rename supportBugNET Issue Tracker: BugNET 0.9.126: First stable release of version 0.9. Upgrades from 0.8 are fully supported and upgrades to future releases will also be supported. This release is now compiled against the .NET 4.0 framework and is a requirement. Because of this the web.config has significantly changed. After upgrading, you will need to configure the authentication settings for user registration and anonymous access again. Please see our installation / upgrade instructions for more details: http://wiki.bugnetproject.c...Anno 2070 Assistant: v0.1.0 (STABLE): Version 0.1.0 Features Production Chains Eco Production Chains (Complete) Tycoon Production Chains (Disabled - Incomplete) Tech Production Chains (Disabled - Incomplete) Supply (Disabled - Incomplete) Calculator (Disabled - Incomplete) Building Layouts Eco Building Layouts (Complete) Tycoon Building Layouts (Disabled - Incomplete) Tech Building Layouts (Disabled - Incomplete) Credits (Complete)Free SharePoint 2010 Sites Templates: SharePoint Server 2010 Sites Templates: here is the list of sites templates to be downloadedVsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 30 Beta: Note: This release does not work with custom VsTortoise toolbars. These get removed every time when you shutdown Visual Studio. (#7940) Build 30 (beta)New: Support for TortoiseSVN 1.7 added. (the download contains both setups, for TortoiseSVN 1.6 and 1.7) New: OpenModifiedDocumentDialog displays conflicted files now. New: OpenModifiedDocument allows to group items by changelist now. Fix: OpenModifiedDocumentDialog caused Visual Studio 2010 to freeze sometimes. Fix: The installer didn...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.30: Highlight features & improvements: • Performance optimization. • Back in stock notifications. • Product special price support. • Catalog mode (based on customer role) To see the full list of fixes and changes please visit the release notes page (http://www.nopCommerce.com/releasenotes.aspx).WPF Converters: WPF Converters V1.2.0.0: support for enumerations, value types, and reference types in the expression converter's equality operators the expression converter now handles DependencyProperty.UnsetValue as argument values correctly (#4062) StyleCop conformance (more or less)Json.NET: Json.NET 4.0 Release 4: Change - JsonTextReader.Culture is now CultureInfo.InvariantCulture by default Change - KeyValurPairConverter no longer cares about the order of the key and value properties Change - Time zone conversions now use new TimeZoneInfo instead of TimeZone Fix - Fixed boolean values sometimes being capitalized when converting to XML Fix - Fixed error when deserializing ConcurrentDictionary Fix - Fixed serializing some Uris returning the incorrect value Fix - Fixed occasional error when...Media Companion: MC 3.423b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) Replaced 'Rebuild' with 'Refresh' throughout entire code. Rebuild will now be known as Refresh. mc_com.exe has been fully updated TV Show Resolutions... Resolved issue #206 - having to hit save twice when updating runtime manually Shrunk cache size and lowered loading times f...Delta Engine: Delta Engine Beta Preview v0.9.1: v0.9.1 beta release with lots of refactoring, fixes, new samples and support for iOS, Android and WP7 (you need a Marketplace account however). If you want a binary release for the games (like v0.9.0), just say so in the Forum or here and we will quickly prepare one. It is just not much different from v0.9.0, so I left it out this time. See http://DeltaEngine.net/Wiki.Roadmap for details.SharpMap - Geospatial Application Framework for the CLR: SharpMap-0.9-AnyCPU-Trunk-2011.11.17: This is a build of SharpMap from the 0.9 development trunk as per 2011-11-17 For most applications the AnyCPU release is the recommended, but in case you need an x86 build that is included to. For some dataproviders (GDAL/OGR, SqLite, PostGis) you need to also referense the SharpMap.Extensions assembly For SqlServer Spatial you need to reference the SharpMap.SqlServerSpatial assemblyAJAX Control Toolkit: November 2011 Release: AJAX Control Toolkit Release Notes - November 2011 Release Version 51116November 2011 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4 - Binary – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 - Binary – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Notes: - The current version of the AJAX Control Toolkit is not compatible with ASP.NET 2.0. The latest version that is compatible with ASP.NET 2.0 can be found h...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.36: Fix for issue #16908: string literals containing ASP.NET replacement syntax fail if the ASP.NET code contains the same character as the string literal delimiter. Also, we shouldn't be changing the delimiter for those literals or combining them with other literals; the developer may have specifically chosen the delimiter used because of possible content inserted by ASP.NET code. This logic is normally off; turn it on via the -aspnet command-line flag (or the Code.Settings.AllowEmbeddedAspNetBl...MVC Controls Toolkit: Mvc Controls Toolkit 1.5.5: Added: Now the DateRanteAttribute accepts complex expressions containing "Now" and "Today" as static minimum and maximum. Menu, MenuFor helpers capable of handling a "currently selected element". The developer can choose between using a standard nested menu based on a standard SimpleMenuItem class or specifying an item template based on a custom class. Added also helpers to build the tree structure containing all data items the menu takes infos from. Improved the pager. Now the developer ...SharpCompress - a fully native C# library for RAR, 7Zip, Zip, Tar, GZip, BZip2: SharpCompress 0.7: Reworked API to be more consistent. See Supported formats table. Added some more helper methods - e.g. OpenEntryStream (RarArchive/RarReader does not support this) Fixed up testsSilverlight Toolkit: Windows Phone Toolkit - Nov 2011 (7.1 SDK): This release is coming soon! What's new ListPicker once again works in a ScrollViewer LongListSelector bug fixes around OutOfRange exceptions, wrong ordering of items, grouping issues, and scrolling events. ItemTuple is now refactored to be the public type LongListSelectorItem to provide users better access to the values in selection changed handlers. PerformanceProgressBar binding fix for IsIndeterminate (item 9767 and others) There is no longer a GestureListener dependency with the C...New ProjectsAndrecorder: Andrecorder???Android???????,???????????????????,????????????????,????????!Android Tree Bulletin: Android bulletin reader in tree format.Bài t?p l?p môn HCI: Name: Ph?n m?m qu?n lý thu h?c phí tru?ng d?i h?c Công Nghi?p Hà N?i Basic Grid Collision sample in XNA: This project shows how to implement a basic grid collision in XNA. The project uses the XNA 4.0 framework and C#Club Manager: Club Manager is a web site for managing sport clubs / teams.Create email with encrypt text implement TEA encryption and Web Service: RahaTEA Mail is an application to send messages in secret. These applications implement TEA encryption and web serviceCRM 2011 Layers: Several .net layers to customize CRM 2011CTEF: China Tomorrow Education Foundation websitedns?????: ??c#???dns?????。????????，???????，??????。EAF: Extensibility Application FrameworkEnergy SBA: In order to compete with large companies for Federal contracts, small business need information. This application seeks to show standard methods of using remote APIs to integrate information into a Metro interface using services provided by the Small Business Administration (SBA)EPiOptimiser - Scan your EPiServer configuration to optimise start up times: EPiScanner scans your EPiServer configuration to optimise start ups by generating a recommended exclude list of assemblies to include in EPiServer framework config. It can be used on command line, as a custom build task or integrated into Visual Studio as an external tool.FreeIDS - Free Intrusion Detection System: Don't want someone to use your computer? Don't want to use a system password? Want to see when someone accessed your computer? Time/Date? FreeIDS is it!FtpServerAdministrator: FtpServerAdministrator makes it easier to administer some ftp server by code, although it can only be used for FileZilla server now. It's developed in C#.GreenPoint Online: Tools and components that help you customize an Office 365 / SharePoint Online Environment.HCC C# Workshop: This project contains the code for the exercises of the HCC C# WorkshopKsigDo - Real time view model syncing across user screens: KsigDo show real time view model syncing across user screens - using ASP.NET, Knockout and SignalR. Real time data syncing across user views *was* hard, especially in web applications. Most of the time, the second user needs to refresh the screen, to see the changes made by first user, or we need to implement some long polling that fetches the data and does the update manually. Now, with SignalR and Knockout, ASP.NET developers can take advantage of view model syncing across users, that...lineseven: ???????????????。Mail Size Labeler for GMail: A small utility that labels large e-mails on your gmail account. This utility scan you gmail account, and adds labels to large e-mail so you can clean your mailbox and free space. The labels this utility adds are: Size 1M-2M Size 2M-5M Size 5M-10M Size 10M-15M Size 15M plus Note: a single e-mail thread may get multiple labels if different e-mails of the thread fit different filters.MathService: Complex digits, standart class extentions etc.MyGameProject: gamesMySQL Connect 2 ASP.NET: Example project to show how to connect MySQL database to ASP.NET web project. IDE: Visual Studio 2010 Pro Programming language: C# Detailed information in the article here: http://epavlov.net/blog/2011/11/13/connect-to-mysql-in-visual-studio/ nl: Nutri Leaf Devomr.event.js: Simple js event injecterPastebin4DotNet: This project is an example of how to consume an API, in this case I consummed the Pastebin API.Pomelo: Pomelo is a website example.QuickDevFrameWork: ????????,??,??,????,ioc ?????postsharp?aopReadable Passphrase Generator: Generates passphrases which are (mostly) grammatically correct but nonsensical. These are easy to remember but difficult to guess (for humans or computers). Developed in C# with a KeePass plugin, console app and public API.Rosyama.ru for Windows Phone 7: ?????????? Windows Phone 7 ??? ???????? ???????? ?? ???? rosyama.ru. ?????????? ??????? ?????????? ? ???????? ????????? ???????. SimpleBatch: As the name suggests, this is a simple batch framework allowing you to define batch jobs in XML format. Thus far, contains a basic selection of processors such as the following; File Email SQL (SQL Server Client) SharePoint Document Library Custom ProcessorSite de Notícias: Projeto de faculdade que consiste na criação de um site de notícias.SPWikiProvisioning: Create update and delete SharePoint wiki pages using feature activation and deactivation handlers.SVN Automated Control With C#: I Created this libaray because I need to control Tortoise SVN automactically with out an interface for my own build server and could not find any resuilts on google to achive this task so I went about creating this libaray which dos most of the task's that I needed. I round that you could control SVN by command line so using that as my basic idear I went about coding the most common commands for SVN most of the commads are done but not all. if you like this libaray then please use it we...TremplinCMS: TremplinCMS is a CMS framework for ASP .NET 4.vlu0206sms: SMSMaker by team0206 developingWCF DataService RequestStream Access on webInvoke HTTP POST: This library provides access to the message body request stream of a WCF Data Service (formerly ADO.NET Data Service), which is not possible with the original WCF Data Service class. You are enabled passing data (e.g. Json, files) via HTTP POST to the request body. It uses the operation context (DbContext) provided by the DataService<T> class to get access to the resquest stream.WebOS: Welcome to join us to build our os projectWp7StarterDantas: Iniciando com Wp7WpfCollaborative3D: WpfCollaborative3DXNA Content Preprocessor: The XNA Content Preprocessor allows you to compile all of your XNA assets outside of your normal XNA project. This means more time building your game or app instead of your content.

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  • Towards Database Continuous Delivery – What Next after Continuous Integration? A Checklist

    - by Ben Rees
    .dbd-banner p{ font-size:0.75em; padding:0 0 10px; margin:0 } .dbd-banner p span{ color:#675C6D; } .dbd-banner p:last-child{ padding:0; } @media ALL and (max-width:640px){ .dbd-banner{ background:#f0f0f0; padding:5px; color:#333; margin-top: 5px; } } -- Database delivery patterns & practices STAGE 4 AUTOMATED DEPLOYMENT If you’ve been fortunate enough to get to the stage where you’ve implemented some sort of continuous integration process for your database updates, then hopefully you’re seeing the benefits of that investment – constant feedback on changes your devs are making, advanced warning of data loss (prior to the production release on Saturday night!), a nice suite of automated tests to check business logic, so you know it’s going to work when it goes live, and so on. But what next? What can you do to improve your delivery process further, moving towards a full continuous delivery process for your database? In this article I describe some of the issues you might need to tackle on the next stage of this journey, and how to plan to overcome those obstacles before they appear. Our Database Delivery Learning Program consists of four stages, really three – source controlling a database, running continuous integration processes, then how to set up automated deployment (the middle stage is split in two – basic and advanced continuous integration, making four stages in total). If you’ve managed to work through the first three of these stages – source control, basic, then advanced CI, then you should have a solid change management process set up where, every time one of your team checks in a change to your database (whether schema or static reference data), this change gets fully tested automatically by your CI server. But this is only part of the story. Great, we know that our updates work, that the upgrade process works, that the upgrade isn’t going to wipe our 4Tb of production data with a single DROP TABLE. But – how do you get this (fully tested) release live? Continuous delivery means being always ready to release your software at any point in time. There’s a significant gap between your latest version being tested, and it being easily releasable. Just a quick note on terminology – there’s a nice piece here from Atlassian on the difference between continuous integration, continuous delivery and continuous deployment. This piece also gives a nice description of the benefits of continuous delivery. These benefits have been summed up by Jez Humble at Thoughtworks as: “Continuous delivery is a set of principles and practices to reduce the cost, time, and risk of delivering incremental changes to users” There’s another really useful piece here on Simple-Talk about the need for continuous delivery and how it applies to the database written by Phil Factor – specifically the extra needs and complexities of implementing a full CD solution for the database (compared to just implementing CD for, say, a web app). So, hopefully you’re convinced of moving on the the next stage! The next step after CI is to get some sort of automated deployment (or “release management”) process set up. But what should I do next? What do I need to plan and think about for getting my automated database deployment process set up? Can’t I just install one of the many release management tools available and hey presto, I’m ready! If only it were that simple. Below I list some of the areas that it’s worth spending a little time on, where a little planning and prep could go a long way. It’s also worth pointing out, that this should really be an evolving process. Depending on your starting point of course, it can be a long journey from your current setup to a full continuous delivery pipeline. If you’ve got a CI mechanism in place, you’re certainly a long way down that path. Nevertheless, we’d recommend evolving your process incrementally. Pages 157 and 129-141 of the book on Continuous Delivery (by Jez Humble and Dave Farley) have some great guidance on building up a pipeline incrementally: http://www.amazon.com/Continuous-Delivery-Deployment-Automation-Addison-Wesley/dp/0321601912 For now, in this post, we’ll look at the following areas for your checklist: You and Your Team Environments The Deployment Process Rollback and Recovery Development Practices You and Your Team It’s a cliché in the DevOps community that “It’s not all about processes and tools, really it’s all about a culture”. As stated in this DevOps report from Puppet Labs: “DevOps processes and tooling contribute to high performance, but these practices alone aren’t enough to achieve organizational success. The most common barriers to DevOps adoption are cultural: lack of manager or team buy-in, or the value of DevOps isn’t understood outside of a specific group”. Like most clichés, there’s truth in there – if you want to set up a database continuous delivery process, you need to get your boss, your department, your company (if relevant) onside. Why? Because it’s an investment with the benefits coming way down the line. But the benefits are huge – for HP, in the book A Practical Approach to Large-Scale Agile Development: How HP Transformed LaserJet FutureSmart Firmware, these are summarized as: -2008 to present: overall development costs reduced by 40% -Number of programs under development increased by 140% -Development costs per program down 78% -Firmware resources now driving innovation increased by a factor of 8 (from 5% working on new features to 40% But what does this mean? It means that, when moving to the next stage, to make that extra investment in automating your deployment process, it helps a lot if everyone is convinced that this is a good thing. That they understand the benefits of automated deployment and are willing to make the effort to transform to a new way of working. Incidentally, if you’re ever struggling to convince someone of the value I’d strongly recommend just buying them a copy of this book – a great read, and a very practical guide to how it can really work at a large org. I’ve spoken to many customers who have implemented database CI who describe their deployment process as “The point where automation breaks down. Up to that point, the CI process runs, untouched by human hand, but as soon as that’s finished we revert to manual.” This deployment process can involve, for example, a DBA manually comparing an environment (say, QA) to production, creating the upgrade scripts, reading through them, checking them against an Excel document emailed to him/her the night before, turning to page 29 in his/her notebook to double-check how replication is switched off and on for deployments, and so on and so on. Painful, error-prone and lengthy. But the point is, if this is something like your deployment process, telling your DBA “We’re changing everything you do and your toolset next week, to automate most of your role – that’s okay isn’t it?” isn’t likely to go down well. There’s some work here to bring him/her onside – to explain what you’re doing, why there will still be control of the deployment process and so on. Or of course, if you’re the DBA looking after this process, you have to do a similar job in reverse. You may have researched and worked out how you’d like to change your methodology to start automating your painful release process, but do the dev team know this? What if they have to start producing different artifacts for you? Will they be happy with this? Worth talking to them, to find out. As well as talking to your DBA/dev team, the other group to get involved before implementation is your manager. And possibly your manager’s manager too. As mentioned, unless there’s buy-in “from the top”, you’re going to hit problems when the implementation starts to get rocky (and what tool/process implementations don’t get rocky?!). You need to have support from someone senior in your organisation – someone you can turn to when you need help with a delayed implementation, lack of resources or lack of progress. Actions: Get your DBA involved (or whoever looks after live deployments) and discuss what you’re planning to do or, if you’re the DBA yourself, get the dev team up-to-speed with your plans, Get your boss involved too and make sure he/she is bought in to the investment. Environments Where are you going to deploy to? And really this question is – what environments do you want set up for your deployment pipeline? Assume everyone has “Production”, but do you have a QA environment? Dedicated development environments for each dev? Proper pre-production? I’ve seen every setup under the sun, and there is often a big difference between “What we want, to do continuous delivery properly” and “What we’re currently stuck with”. Some of these differences are: What we want What we’ve got Each developer with their own dedicated database environment A single shared “development” environment, used by everyone at once An Integration box used to test the integration of all check-ins via the CI process, along with a full suite of unit-tests running on that machine In fact if you have a CI process running, you’re likely to have some sort of integration server running (even if you don’t call it that!). Whether you have a full suite of unit tests running is a different question… Separate QA environment used explicitly for manual testing prior to release “We just test on the dev environments, or maybe pre-production” A proper pre-production (or “staging”) box that matches production as closely as possible Hopefully a pre-production box of some sort. But does it match production closely!? A production environment reproducible from source control A production box which has drifted significantly from anything in source control The big question is – how much time and effort are you going to invest in fixing these issues? In reality this just involves figuring out which new databases you’re going to create and where they’ll be hosted – VMs? Cloud-based? What about size/data issues – what data are you going to include on dev environments? Does it need to be masked to protect access to production data? And often the amount of work here really depends on whether you’re working on a new, greenfield project, or trying to update an existing, brownfield application. There’s a world if difference between starting from scratch with 4 or 5 clean environments (reproducible from source control of course!), and trying to re-purpose and tweak a set of existing databases, with all of their surrounding processes and quirks. But for a proper release management process, ideally you have: Dedicated development databases, An Integration server used for testing continuous integration and running unit tests. [NB: This is the point at which deployments are automatic, without human intervention. Each deployment after this point is a one-click (but human) action], QA – QA engineers use a one-click deployment process to automatically* deploy chosen releases to QA for testing, Pre-production. The environment you use to test the production release process, Production. * A note on the use of the word “automatic” – when carrying out automated deployments this does not mean that the deployment is happening without human intervention (i.e. that something is just deploying over and over again). It means that the process of carrying out the deployment is automatic in that it’s not a person manually running through a checklist or set of actions. The deployment still requires a single-click from a user. Actions: Get your environments set up and ready, Set access permissions appropriately, Make sure everyone understands what the environments will be used for (it’s not a “free-for-all” with all environments to be accessed, played with and changed by development). The Deployment Process As described earlier, most existing database deployment processes are pretty manual. The following is a description of a process we hear very often when we ask customers “How do your database changes get live? How does your manual process work?” Check pre-production matches production (use a schema compare tool, like SQL Compare). Sometimes done by taking a backup from production and restoring in to pre-prod, Again, use a schema compare tool to find the differences between the latest version of the database ready to go live (i.e. what the team have been developing). This generates a script, User (generally, the DBA), reviews the script. This often involves manually checking updates against a spreadsheet or similar, Run the script on pre-production, and check there are no errors (i.e. it upgrades pre-production to what you hoped), If all working, run the script on production.* * this assumes there’s no problem with production drifting away from pre-production in the interim time period (i.e. someone has hacked something in to the production box without going through the proper change management process). This difference could undermine the validity of your pre-production deployment test. Red Gate is currently working on a free tool to detect this problem – sign up here at www.sqllighthouse.com, if you’re interested in testing early versions. There are several variations on this process – some better, some much worse! How do you automate this? In particular, step 3 – surely you can’t automate a DBA checking through a script, that everything is in order!? The key point here is to plan what you want in your new deployment process. There are so many options. At one extreme, pure continuous deployment – whenever a dev checks something in to source control, the CI process runs (including extensive and thorough testing!), before the deployment process keys in and automatically deploys that change to the live box. Not for the faint hearted – and really not something we recommend. At the other extreme, you might be more comfortable with a semi-automated process – the pre-production/production matching process is automated (with an error thrown if these environments don’t match), followed by a manual intervention, allowing for script approval by the DBA. One he/she clicks “Okay, I’m happy for that to go live”, the latter stages automatically take the script through to live. And anything in between of course – and other variations. But we’d strongly recommended sitting down with a whiteboard and your team, and spending a couple of hours mapping out “What do we do now?”, “What do we actually want?”, “What will satisfy our needs for continuous delivery, but still maintaining some sort of continuous control over the process?” NB: Most of what we’re discussing here is about production deployments. It’s important to note that you will also need to map out a deployment process for earlier environments (for example QA). However, these are likely to be less onerous, and many customers opt for a much more automated process for these boxes. Actions: Sit down with your team and a whiteboard, and draw out the answers to the questions above for your production deployments – “What do we do now?”, “What do we actually want?”, “What will satisfy our needs for continuous delivery, but still maintaining some sort of continuous control over the process?” Repeat for earlier environments (QA and so on). Rollback and Recovery If only every deployment went according to plan! Unfortunately they don’t – and when things go wrong, you need a rollback or recovery plan for what you’re going to do in that situation. Once you move in to a more automated database deployment process, you’re far more likely to be deploying more frequently than before. No longer once every 6 months, maybe now once per week, or even daily. Hence the need for a quick rollback or recovery process becomes paramount, and should be planned for. NB: These are mainly scenarios for handling rollbacks after the transaction has been committed. If a failure is detected during the transaction, the whole transaction can just be rolled back, no problem. There are various options, which we’ll explore in subsequent articles, things like: Immediately restore from backup, Have a pre-tested rollback script (remembering that really this is a “roll-forward” script – there’s not really such a thing as a rollback script for a database!) Have fallback environments – for example, using a blue-green deployment pattern. Different options have pros and cons – some are easier to set up, some require more investment in infrastructure; and of course some work better than others (the key issue with using backups, is loss of the interim transaction data that has been added between the failed deployment and the restore). The best mechanism will be primarily dependent on how your application works and how much you need a cast-iron failsafe mechanism. Actions: Work out an appropriate rollback strategy based on how your application and business works, your appetite for investment and requirements for a completely failsafe process. Development Practices This is perhaps the more difficult area for people to tackle. The process by which you can deploy database updates is actually intrinsically linked with the patterns and practices used to develop that database and linked application. So you need to decide whether you want to implement some changes to the way your developers actually develop the database (particularly schema changes) to make the deployment process easier. A good example is the pattern “Branch by abstraction”. Explained nicely here, by Martin Fowler, this is a process that can be used to make significant database changes (e.g. splitting a table) in a step-wise manner so that you can always roll back, without data loss – by making incremental updates to the database backward compatible. Slides 103-108 of the following slidedeck, from Niek Bartholomeus explain the process: https://speakerdeck.com/niekbartho/orchestration-in-meatspace As these slides show, by making a significant schema change in multiple steps – where each step can be rolled back without any loss of new data – this affords the release team the opportunity to have zero-downtime deployments with considerably less stress (because if an increment goes wrong, they can roll back easily). There are plenty more great patterns that can be implemented – the book Refactoring Databases, by Scott Ambler and Pramod Sadalage is a great read, if this is a direction you want to go in: http://www.amazon.com/Refactoring-Databases-Evolutionary-paperback-Addison-Wesley/dp/0321774515 But the question is – how much of this investment are you willing to make? How often are you making significant schema changes that would require these best practices? Again, there’s a difference here between migrating old projects and starting afresh – with the latter it’s much easier to instigate best practice from the start. Actions: For your business, work out how far down the path you want to go, amending your database development patterns to “best practice”. It’s a trade-off between implementing quality processes, and the necessity to do so (depending on how often you make complex changes). Socialise these changes with your development group. No-one likes having “best practice” changes imposed on them, so good to introduce these ideas and the rationale behind them early.   Summary The next stages of implementing a continuous delivery pipeline for your database changes (once you have CI up and running) require a little pre-planning, if you want to get the most out of the work, and for the implementation to go smoothly. We’ve covered some of the checklist of areas to consider – mainly in the areas of “Getting the team ready for the changes that are coming” and “Planning our your pipeline, environments, patterns and practices for development”, though there will be more detail, depending on where you’re coming from – and where you want to get to. This article is part of our database delivery patterns & practices series on Simple Talk. Find more articles for version control, automated testing, continuous integration & deployment.

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  • CodePlex Daily Summary for Sunday, August 10, 2014

    CodePlex Daily Summary for Sunday, August 10, 2014Popular ReleasesWinForms MVP: WinForms MVP v1.0.1008.2014: Issues Fixed Issue 1 New Added MessageBus and AppState features. Added tests in support of the MessageBus and AppState features Added dependency injection support for Ninject. Added tests in support of the NinjectPresenterFactory.WP8 Native Access Webserver: Version alpha 0.5.3: Figured I should post a newer version. This build includes pretty broad registry browsing (especially if you can use the AllCapabilities version) and (in the AC version) also fairly broad file system access. It also includes the ability to download .REG files. There have been tons of bugfixes and performance improvements as well, plus a slightly better UI in both the app and the web interface. For more info, please read the forum post here: http://forum.xda-developers.com/showthread.php?t=23...ClosedXML - The easy way to OpenXML: ClosedXML 0.74.0: Many updates. See history.SEToolbox: SEToolbox 01.042.019 Release 1: Added RadioAntenna broadcast name to ship name detail. Added two additional columns for Asteroid material generation for Asteroid Fields. Added Mass and Block number columns to main display. Added Ellipsis to some columns on main display to reduce name confusion. Added correct SE version number in file when saving. Re-added in reattaching Motor when drag/dropping or importing ships (KeenSH have added RotorEntityId back in after removing it months ago). Added option to export and r...Instant Beautiful Browsing: IBB 14.3 Alpha: An alpha release of IBB. After 3 years of the last release this version is made from scratch, with tons of new features like: Make your own IBB aps. HTML 5. Better UI. Extreme Windows 8 resemblance. Photos. Store. Movement TONS of times smother compared to previous versions. Remember that this is AN ALPHA release, I hope I will have "IBB 14" finished by December. The documentation on how to create a new application for IBB will come next monthjQuery List DragSort: jQuery List DragSort 0.5.2: Fixed scrollContainer removing deprecated use of $.browser so should now work with latest version of jQuery. Added the ability to return false in dragEnd to revert sort order Project changes Added nuget package for dragsort https://www.nuget.org/packages/dragsort Converted repository from SVN to MercurialCRM 2013 One Click Navigation: CRM2013OneClickNavigation_1_0_0_4_managed.zip: Fixed some minor issues and added support for the following languages Spanish German French Italian Portuguese Russian Arabic Chinese Japanese Hindi Hebrew Korean Polish ThaiBraintree Client Library: Braintree 2.32.0: Allow credit card verification options to be passed outside of the nonce for PaymentMethod.create Allow billingaddress parameters and billingaddress_id to be passed outside of the nonce for PaymentMethod.create Add Subscriptions to paypal accounts Add PaymentMethod.update Add failonduplicatepaymentmethod option to PaymentMethod.create Add support for dispute webhooksThe Mario Kart 8 App: V1.0.2.1: First Codeplex release. WINDOWS INSTALLER ONLYAspose Java for Docx4j: Aspose.Words vs Docx4j - v 1.0: Release contain the Code Comparison for Features in Docx4j SDK and Aspose.Words What's New ?Following Examples: Accessing Document Properties Add Bookmarks Convert to Formats Delete Bookmarks Working with Comments Feedback and Suggestions Many more examples are available at Aspose Docs. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.File System Security PowerShell Module: NTFSSecurity 2.4.1: Add-Access and Remove-Access now take multiple accoutsYourSqlDba: YourSqlDba 5.2.1.: This version improves alert message that comes a while after you install the script. First it says to get it from YourSqlDba.CodePlex.com If you don't want to update now, just-rerun the script from your installed version. To get actual version running just execute install.PrintVersionInfo. . You can go to source code / history and click on change set 72957 to see changes in the script.Manipulator: Manipulator: manipulatorXNB filetype plugin for Paint.NET: Paint.NET XNB plugin v0.4.0.0: CHANGELOG Reverted old incomplete changes. Updated library for compatibility with Paint .NET 4. Updated project to NET 4.5. Updated version to 0.4.0.0. INSTALLATION INSTRUCTIONS Extract the ZIP file to your Paint.NET\FileTypes folder.EdiFabric: Release 4.1: Changed MessageContextWix# (WixSharp) - managed interface for WiX: Release 1.0.0.0: Release 1.0.0.0 Custom UI Custom MSI Dialog Custom CLR Dialog External UIMath.NET Numerics: Math.NET Numerics v3.2.0: Linear Algebra: Vector.Map2 (map2 in F#), storage-optimized Linear Algebra: fix RemoveColumn/Row early index bound check (was not strict enough) Statistics: Entropy ~Jeff Mastry Interpolation: use Array.BinarySearch instead of local implementation ~Candy Chiu Resources: fix a corrupted exception message string Portable Build: support .Net 4.0 as well by using profile 328 instead of 344. .Net 3.5: F# extensions now support .Net 3.5 as well .Net 3.5: NuGet package now contains pro...Virto Commerce Enterprise Open Source eCommerce Platform (asp.net mvc): Virto Commerce 1.11: Virto Commerce Community Edition version 1.11. To install the SDK package, please refer to SDK getting started documentation To configure source code package, please refer to Source code getting started documentation This release includes many bug fixes and minor improvements. More details about this release can be found on our blog at http://blog.virtocommerce.com.BoxStarter: Boxstarter 2.4.80: Running the Setup.bat file will install Chocolatey if not present and then install the Boxstarter modules.ProjkyAddin ssms addin script shortcut ssmsaddin: projkyaddin source code and msi files.: projkyaddin source code and msi files.New ProjectsBolos: BolosBWQS - The BitWise Query Service: Generic object queries with a bitwise syntax.DocX Razor: A DocX scaffolding engine with Razor syntaxJQuery Simple Logger: Its a very simple jQuery extension for logging client side events. There are four levels of logging: Error, Warning, Info, Debug ???????: ???????QQ:2281595668，?????，????，????　　?????????????????????，??1998?7??????，??????????，?????????，?????????????，????????????????????????. ????????????????????，????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，?????????: ???????????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，????????????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，????????????????: ????????????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ:2281595668，?????，????，????。??????????????????，????????。????????????????、???????。??????????????。?????????????????,??????,??????,??????,??????????????，????????: ??????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ???????????: ??????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，????????????????: ??????QQ:2281595668，?????，????，????　　 ????????????????????，??1998?7??????，??????????，??????? ????????，?????????????， ???????????????????????. ???????????????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ????????????: ??????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，????????????，????，??“??????”????????: ??????QQ:2281595668，?????，????，????。??????????????????????????，????????????!??????????????????????????????????????????、???????、????、??????、??????????。???????????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ???????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ??????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“???????????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、???????????????: ????????????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ:2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，???????: ??????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????????: ???????????: ????????????: ????????????: ????????????: ????????????QQ:2281595668，?????，????，????　　???????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????: ?????????????: ???????QQ：2281595668，?????，????，????。???????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，??????????????: ??????QQ：2281595668，?????，????，????。???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????????????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，????????????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，?????????????????????????????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，?????????????????: ??????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ????????????: ?????????????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”?????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ:2281595668，?????，????，????。?????????????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，?????????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ:2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ??????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ:2281595668，?????，????，????　　???????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ?????????????: ??????????????QQ:2281595668，?????，????，????　　?????????????????????，??1998?7??????，??????????，?????????，?????????????，????????????????????????. ??????????????????????: ???????????: ????????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;???????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ?????QQ:2281595668，?????，????，????　　??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;?????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。??????????????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ??????????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”??????????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，????????????????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????: ?????QQ：2281595668，?????，????，????。?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ:2281595668，?????，????，????　　??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ??????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，???????: ????????????: ?????????????: hhhtbjzjgh??????: ??????QQ：2281595668，?????，????，????。??????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????????: ?????QQ:2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ:2281595668，?????，????，????。　　?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，???????: ??????QQ:2281595668，?????，????，????。??????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，????????????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;???????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ：2281595668，?????，????，????。???????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，??????????????????????????????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ??????QQ:2281595668，?????，????，????。???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????、??????????: ????????????QQ:2281595668，?????，????，????　　???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????????: ???????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，?????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ:2281595668，?????，????，????　　??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，???????????????????????????????: tybjza?????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，????????????????: ??????QQ:2281595668，?????，????，????。　　??????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，??????????????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,????????: ????????QQ:2281595668，?????，????，????　　?????????????????????????????,?????????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;??????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;??????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ????????????QQ:2281595668，?????，????，????　　???????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，???????????????????????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。??????????????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，????????????????????????????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? 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??。???????????，??????????，???????????，????2000?，??????????，??????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ???????????: ????????????: ??????QQ：2281595668，?????，????，????。　　???????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，????????: ?????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,???????????????????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，??????????????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????????????: ???????QQ:2281595668，?????，????，????。?????????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????????: ???????????: ?????QQ:2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ??????????????: ????????QQ:2281595668，?????，????，????　　?????????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，?????????????????????????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，??????: ?????QQ:2281595668，?????，????，????。????????????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，?????????????????: ????????????: ?????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ????????????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;??????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、??????: ?????QQ:2281595668，?????，????，????。　　?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，???????: ???????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ????????????: ???????????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。???????????????????: ??????QQ:2281595668，?????，????，????　　???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????、??????????: ???????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ?????????: ?????QQ:2281595668，?????，????，????　　???????????????????，????????????，??????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，????????: ??????????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”?????????: ?????QQ：2281595668，?????，????，????。???????????????????，??1998?7??????，??????????，?????????，?????????????，??????????????????????. ????????????????????，???????????????: ?????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ?????，??????: ???????????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ????????????: ??????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，???????????????: ??????QQ:2281595668，?????，????，????　　????????????????????，??1998?7??????，??????????，?????????，?????????????，???????????????????????. ????????????????????，???????????: ?????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”?????????: ?????????????????: ??????????????????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ：2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ????????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，????????????，????，??“????????: ?????QQ:2281595668，?????，????，????。?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????。??????????????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,??????: ????????????: ??????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ??????????: ?????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ?????，?????: ?????QQ:2281595668，?????，????，????。??????????????，?????????????????????，???????????????????????!?????????????????????????????????????????????、?????????、??????、???????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ??????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，???????? ??????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、???????????????: ??????QQ:2281595668，?????，????，????。???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;?????????: ????????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，?????: ?????QQ：2281595668，?????，????，????。?????????????????，????????。????????????????、???????。??????????????。????????????????,??????,??????,??????,??????????????，????,?????: ??????????: ????????????: ????????????: ??????????: ????? QQ:2281595668，?????，????，????。????? ?????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，???????????????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。????????，??????????????????????。????????，????????????，??????: ??????QQ:2281595668，?????，????，????　　???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;???????: ?????QQ:2281595668，?????，????，????。?????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，???????????，??????: ??????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，??????: ?????QQ：2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，??????，???????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。????????，??????????????????????。????????，????????????，????????: ????????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，??????????????，????，??“???????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ????????????: ??????QQ：2281595668，?????，????，????。????????????????????，??1998?7??????，??????????，?????????，?????????????，???????????????????????. ????????????????????，?????????????: ???????????: ?????QQ:2281595668，?????，????，????　　??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，???????????????????????????????: ?????QQ：2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ????????????QQ:2281595668，?????，????，????　　????? ????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，??????????????: ??????QQ:2281595668，?????，????，????。??????????????????，????????。????????????????、???????。??????????????。?????????????????,??????,??????,??????,??????????????，????????: ????????????: ????????????QQ:2281595668，?????，????，????　　?????2004?，??????????????，??????????????????。?????? ?????，????????????????，????????????。????，????????????，????，??“????????: ???????????: ?????????????: ???????QQ:2281595668，?????，????，????。????????????????，?????????????????????，?????????????????????????!???????????????????????????????????????????????、?????????、??????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????????: ?????QQ:2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ???????????: ?????QQ:2281595668，?????，????，????。???????????????????，??????????????，????，?????????????????????，??????。???????，??????????????????????。????????，????????????，?????????: ??????QQ:2281595668，?????，????，????。??????????????????????????，????????????!??????????????????????????????????????????、???????、????、??????、??????????。????????????????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。????????，??????????????????????。????????，????????????，??????: ??????QQ:2281595668，?????，????，????。?????????????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，??????????????: ????????????: ???????????: ?????QQ:2281595668，?????，????，????。??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;???????: ????????????: ????????????: ??????QQ:2281595668，?????，????，????　　???????????????????，????????????，???????98???????????，????，??????????，?????????. 　　?????????,????????????????，???????????，???????: ??????QQ:2281595668，?????，????，????。???????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，???????????????: ??????QQ:2281595668，?????，????，????。???????????????，?????????????????????，????????????????????????!??????????????????????????????????????????????、?????????、?????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、??????????????: ?????QQ：2281595668，?????，????，????。??????????????，?????????????????????????，????????????!?????????????????????????????????????????、???????、????、??????、???????????????: ??????QQ:2281595668，?????，????，????。???????????????????????????,???????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????????: ?????QQ:2281595668，?????，????，????　　????????????????????，????????。????????????????、???????。??????????????。???????????????????,??????,??????,??????,??????????????????: ?????QQ:2281595668，?????，????，????。　　?????????????、??、??、??????????????????，???????，???????，?????????????，??????????????，?????、??????????、??、???，?????????????，???????: ??????QQ:2281595668，?????，????，????。??????????????????!????????????????????????????????????????????、?????????、??????、????????、????????????。??????????，????????????????: ???????????: ?????QQ：2281595668，?????，????，????。　　??????98???????????，???????????????????，????????????，????，??????????，?????????，?????????,????????????????，???????????，??????????: ?????QQ：2281595668，?????，????，????。??????????1998?????????。????????????，???????????????，?????????????，???????????，?2003?????????????，?????????????????????????????????: ????????????: ????????????: ??????QQ:2281595668，?????，????，????。????????????????????，??????????????，????，?????????????????????，??????。??，??????????????????????。????????，????????????，????????????: ????????????: ???????????: ?????QQ：2281595668，?????，????，????。?????????，??????????????????。?????? ?????，????????????????，????????????。????，???????????，????，??“??????”???? ?????，???????????????: ?????QQ:2281595668，?????，????，????　　??????????????????????????,??????????,???????????????????????,???????:????,????;?????????????;??;??;????;????????;????;????;?????: ?????QQ：2281595668，?????，????，????。??????????????，??????、????、?????????????????????????，???????????? ??。???????????，??????????，???????????，????2000?，??????????，??????: ??????

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  • Dynamically loading Assemblies to reduce Runtime Depencies

    - by Rick Strahl
    I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change.  So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. That being said though - I serialized 10,000 objects in 80ms vs. 45ms so this isn't hardly slouchy. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?On occasion dynamic loading makes sense. But there's a price to be paid in added code complexity and a performance hit. But for some operations that are not pivotal to a component or application and only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful tool. Hopefully some of you find this information useful…© Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET  C#   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

    - by Rhames
    ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO   CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40)   DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10   WHILE @DayCount < 5000  BEGIN  INSERT Sale VALUES (@DayCount,@Sales)  SET @DayCount = @DayCount + 1  SET @Sales = @Sales + 15  END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO   SET ANSI_NULLS ON GO   SET QUOTED_IDENTIFIER ON GO   -- ============================================= -- Author:        Robin -- Create date: -- Description:   -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals]       -- Add the parameters for the stored procedure here       @HighestDayCount smallint = null AS BEGIN       -- SET NOCOUNT ON added to prevent extra result sets from       -- interfering with SELECT statements.       SET NOCOUNT ON;         IF @HighestDayCount IS NULL             SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale                   DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money)         DECLARE @DayCount smallint,                   @Sales money,                   @RunningTotal money         SET @RunningTotal = 0       SET @DayCount = 0         DECLARE rt_cursor CURSOR       FOR       SELECT DayCount, Sales       FROM Sale       ORDER BY DayCount         OPEN rt_cursor         FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales         WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount        BEGIN        SET @RunningTotal = @RunningTotal + @Sales        INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal)        FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales        END         CLOSE rt_cursor       DEALLOCATE rt_cursor         SELECT DayCount, Sales, RunningTotal       FROM @SaleTbl   END   GO   Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient;   namespace CacheSample.BusinessObjects {     public class Sale     {         public Int16 DayCount { get; set; }         public decimal Sales { get; set; }         public decimal RunningTotal { get; set; }           public static IEnumerable<Sale> GetSales(int? highestDayCount)         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString;               using(SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         }     } }   The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">     <title>Cache Sample - Show All Sales</title> </head> <body>     <form id="form1" runat="server">     <div>         <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click"             Text="Get All Sales" />         &nbsp;&nbsp;&nbsp;         <asp:Label ID="lblResults" runat="server"></asp:Label>         </div>     </form> </body> </html>   ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;   using CacheSample.BusinessObjects;   namespace CacheSample.UI {     public partial class ShowSales : System.Web.UI.Page     {         protected void Page_Load(object sender, EventArgs e)         {         }           protected void btnTest1_Click(object sender, EventArgs e)         {             System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch();             stopWatch.Start();               var sales = Sale.GetSales(null);               var lastSales = sales.Last();               stopWatch.Stop();               lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds);         }       } }   Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?>   <configuration>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic;   namespace CacheSample.Caching {     public interface ICacheProvider     {     }       public interface ICacheProvider<T> : ICacheProvider     {         T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);           IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);     } }   The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic;   using CacheSample.Caching.Configuration;   namespace CacheSample.Caching {     public static class CacheProviderFactory     {         private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>();         private static object syncRoot = new object();           ///<summary>         /// Factory method to create or retrieve an implementation of the  /// ICacheProvider interface for type <typeparamref name="T"/>.         ///</summary>         ///<typeparam name="T">  /// The type that this cache provider instance will work with  ///</typeparam>         ///<returns>An instance of the implementation of ICacheProvider for type  ///<typeparamref name="T"/>, as specified by the application  /// configuration</returns>         public static ICacheProvider<T> GetCacheProvider<T>()         {             ICacheProvider<T> cacheProvider = null;             // Get the Type reference for the type parameter T             Type typeOfT = typeof(T);               // Lock the access to the cacheProviders dictionary             // so multiple threads can work with it             lock (syncRoot)             {                 // First check if an instance of the ICacheProvider implementation  // already exists in the cacheProviders dictionary for the type T                 if (cacheProviders.ContainsKey(typeOfT))                     cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT];                 else                 {                     // There is not already an instance of the ICacheProvider in       // cacheProviders for the type T                     // so we need to create one                       // Get the Type reference for the application's implementation of       // ICacheProvider from the configuration                     Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType);                     if (cacheProviderType != null)                     {                         // Now get a Type reference for the Cache Provider with the                         // type T generic parameter                         Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT });                         if (typeOfCacheProviderTypeForT != null)                         {                             // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use                             cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT);                             cacheProviders.Add(typeOfT, cacheProvider);                         }                     }                 }             }               return cacheProvider;                 }     } }   As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration;   namespace CacheSample.Caching.Configuration {     internal class CacheProviderConfigurationSection : ConfigurationSection     {         public static CacheProviderConfigurationSection Current         {             get             {                 return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider");             }         }           [ConfigurationProperty("type", IsRequired=true)]         public string CacheProviderType         {             get             {                 return (string)this["type"];             }         }     } }   Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) {     string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount);       return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey,         delegate()         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString;               using (SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         },         null,         new TimeSpan(0, 10, 0)); }     This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching;   using CacheSample.Caching;   namespace CacheSample.CacheProvider {     public class AspNetCacheProvider<T> : ICacheProvider<T>     {         #region ICacheProvider<T> Members           public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           #endregion           #region Helper Methods           private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             U value;             if (!TryGetValue<U>(key, out value))             {                 value = retrieveData();                 if (!absoluteExpiry.HasValue)                     absoluteExpiry = Cache.NoAbsoluteExpiration;                   if (!relativeExpiry.HasValue)                     relativeExpiry = Cache.NoSlidingExpiration;                   HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value);             }             return value;         }           private bool TryGetValue<U>(string key, out U value)         {             object cachedValue = HttpContext.Current.Cache.Get(key);             if (cachedValue == null)             {                 value = default(U);                 return false;             }             else             {                 try                 {                     value = (U)cachedValue;                     return true;                 }                 catch                 {                     value = default(U);                     return false;                 }             }         }           #endregion       } }   The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?>   <configuration>  <configSections>     <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" />  </configSections>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">  </cacheProvider>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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  • Sniffing out SQL Code Smells: Inconsistent use of Symbolic names and Datatypes

    - by Phil Factor
    It is an awkward feeling. You’ve just delivered a database application that seems to be working fine in production, and you just run a few checks on it. You discover that there is a potential bug that, out of sheer good chance, hasn’t kicked in to produce an error; but it lurks, like a smoking bomb. Worse, maybe you find that the bug has started its evil work of corrupting the data, but in ways that nobody has, so far detected. You investigate, and find the damage. You are somehow going to have to repair it. Yes, it still very occasionally happens to me. It is not a nice feeling, and I do anything I can to prevent it happening. That’s why I’m interested in SQL code smells. SQL Code Smells aren’t necessarily bad practices, but just show you where to focus your attention when checking an application. Sometimes with databases the bugs can be subtle. SQL is rather like HTML: the language does its best to try to carry out your wishes, rather than to be picky about your bugs. Most of the time, this is a great benefit, but not always. One particular place where this can be detrimental is where you have implicit conversion between different data types. Most of the time it is completely harmless but we’re  concerned about the occasional time it isn’t. Let’s give an example: String truncation. Let’s give another even more frightening one, rounding errors on assignment to a number of different precision. Each requires a blog-post to explain in detail and I’m not now going to try. Just remember that it is not always a good idea to assign data to variables, parameters or even columns when they aren’t the same datatype, especially if you are relying on implicit conversion to work its magic.For details of the problem and the consequences, see here:  SR0014: Data loss might occur when casting from {Type1} to {Type2} . For any experienced Database Developer, this is a more frightening read than a Vampire Story. This is why one of the SQL Code Smells that makes me edgy, in my own or other peoples’ code, is to see parameters, variables and columns that have the same names and different datatypes. Whereas quite a lot of this is perfectly normal and natural, you need to check in case one of two things have gone wrong. Either sloppy naming, or mixed datatypes. Sure it is hard to remember whether you decided that the length of a log entry was 80 or 100 characters long, or the precision of a number. That is why a little check like this I’m going to show you is excellent for tidying up your code before you check it back into source Control! 1/ Checking Parameters only If you were just going to check parameters, you might just do this. It simply groups all the parameters, either input or output, of all the routines (e.g. stored procedures or functions) by their name and checks to see, in the HAVING clause, whether their data types are all the same. If not, it lists all the examples and their origin (the routine) Even this little check can occasionally be scarily revealing. ;WITH userParameter AS  ( SELECT   c.NAME AS ParameterName,  OBJECT_SCHEMA_NAME(c.object_ID) + '.' + OBJECT_NAME(c.object_ID) AS ObjectName,  t.name + ' '     + CASE     --we may have to put in the length            WHEN t.name IN ('char', 'varchar', 'nchar', 'nvarchar')             THEN '('               + CASE WHEN c.max_length = -1 THEN 'MAX'                ELSE CONVERT(VARCHAR(4),                    CASE WHEN t.name IN ('nchar', 'nvarchar')                      THEN c.max_length / 2 ELSE c.max_length                    END)                END + ')'         WHEN t.name IN ('decimal', 'numeric')             THEN '(' + CONVERT(VARCHAR(4), c.precision)                   + ',' + CONVERT(VARCHAR(4), c.Scale) + ')'         ELSE ''      END  --we've done with putting in the length      + CASE WHEN XML_collection_ID <> 0         THEN --deal with object schema names             '(' + CASE WHEN is_XML_Document = 1                    THEN 'DOCUMENT '                    ELSE 'CONTENT '                   END              + COALESCE(               (SELECT QUOTENAME(ss.name) + '.' + QUOTENAME(sc.name)                FROM sys.xml_schema_collections sc                INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID                WHERE sc.xml_collection_ID = c.XML_collection_ID),'NULL') + ')'          ELSE ''         END        AS [DataType]  FROM sys.parameters c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID  WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys'   AND parameter_id>0)SELECT CONVERT(CHAR(80),objectName+'.'+ParameterName),DataType FROM UserParameterWHERE ParameterName IN   (SELECT ParameterName FROM UserParameter    GROUP BY ParameterName    HAVING MIN(Datatype)<>MAX(DataType))ORDER BY ParameterName   so, in a very small example here, we have a @ClosingDelimiter variable that is only CHAR(1) when, by the looks of it, it should be up to ten characters long, or even worse, a function that should be a char(1) and seems to let in a string of ten characters. Worth investigating. Then we have a @Comment variable that can't decide whether it is a VARCHAR(2000) or a VARCHAR(MAX) 2/ Columns and Parameters Actually, once we’ve cleared up the mess we’ve made of our parameter-naming in the database we’re inspecting, we’re going to be more interested in listing both columns and parameters. We can do this by modifying the routine to list columns as well as parameters. Because of the slight complexity of creating the string version of the datatypes, we will create a fake table of both columns and parameters so that they can both be processed the same way. After all, we want the datatypes to match Unfortunately, parameters do not expose all the attributes we are interested in, such as whether they are nullable (oh yes, subtle bugs happen if this isn’t consistent for a datatype). We’ll have to leave them out for this check. Voila! A slight modification of the first routine ;WITH userObject AS  ( SELECT   Name AS DataName,--the actual name of the parameter or column ('@' removed)  --and the qualified object name of the routine  OBJECT_SCHEMA_NAME(ObjectID) + '.' + OBJECT_NAME(ObjectID) AS ObjectName,  --now the harder bit: the definition of the datatype.  TypeName + ' '     + CASE     --we may have to put in the length. e.g. CHAR (10)           WHEN TypeName IN ('char', 'varchar', 'nchar', 'nvarchar')             THEN '('               + CASE WHEN MaxLength = -1 THEN 'MAX'                ELSE CONVERT(VARCHAR(4),                    CASE WHEN TypeName IN ('nchar', 'nvarchar')                      THEN MaxLength / 2 ELSE MaxLength                    END)                END + ')'         WHEN TypeName IN ('decimal', 'numeric')--a BCD number!             THEN '(' + CONVERT(VARCHAR(4), Precision)                   + ',' + CONVERT(VARCHAR(4), Scale) + ')'         ELSE ''      END  --we've done with putting in the length      + CASE WHEN XML_collection_ID <> 0 --tush tush. XML         THEN --deal with object schema names             '(' + CASE WHEN is_XML_Document = 1                    THEN 'DOCUMENT '                    ELSE 'CONTENT '                   END              + COALESCE(               (SELECT TOP 1 QUOTENAME(ss.name) + '.' + QUOTENAME(sc.Name)                FROM sys.xml_schema_collections sc                INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID                WHERE sc.xml_collection_ID = XML_collection_ID),'NULL') + ')'          ELSE ''         END        AS [DataType],       DataObjectType  FROM   (Select t.name AS TypeName, REPLACE(c.name,'@','') AS Name,          c.max_length AS MaxLength, c.precision AS [Precision],           c.scale AS [Scale], c.[Object_id] AS ObjectID, XML_collection_ID,          is_XML_Document,'P' AS DataobjectType  FROM sys.parameters c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID  AND parameter_id>0  UNION all  Select t.name AS TypeName, c.name AS Name, c.max_length AS MaxLength,          c.precision AS [Precision], c.scale AS [Scale],          c.[Object_id] AS ObjectID, XML_collection_ID,is_XML_Document,          'C' AS DataobjectType            FROM sys.columns c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID   WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys'  )f)SELECT CONVERT(CHAR(80),objectName+'.'   + CASE WHEN DataobjectType ='P' THEN '@' ELSE '' END + DataName),DataType FROM UserObjectWHERE DataName IN   (SELECT DataName FROM UserObject   GROUP BY DataName    HAVING MIN(Datatype)<>MAX(DataType))ORDER BY DataName     Hmm. I can tell you I found quite a few minor issues with the various tabases I tested this on, and found some potential bugs that really leap out at you from the results. Here is the start of the result for AdventureWorks. Yes, AccountNumber is, for some reason, a Varchar(10) in the Customer table. Hmm. odd. Why is a city fifty characters long in that view?  The idea of the description of a colour being 256 characters long seems over-ambitious. Go down the list and you'll spot other mistakes. There are no bugs, but just mess. We started out with a listing to examine parameters, then we mixed parameters and columns. Our last listing is for a slightly more in-depth look at table columns. You’ll notice that we’ve delibarately removed the indication of whether a column is persisted, or is an identity column because that gives us false positives for our code smells. If you just want to browse your metadata for other reasons (and it can quite help in some circumstances) then uncomment them! ;WITH userColumns AS  ( SELECT   c.NAME AS columnName,  OBJECT_SCHEMA_NAME(c.object_ID) + '.' + OBJECT_NAME(c.object_ID) AS ObjectName,  REPLACE(t.name + ' '   + CASE WHEN is_computed = 1 THEN ' AS ' + --do DDL for a computed column          (SELECT definition FROM sys.computed_columns cc           WHERE cc.object_id = c.object_id AND cc.column_ID = c.column_ID)     --we may have to put in the length            WHEN t.Name IN ('char', 'varchar', 'nchar', 'nvarchar')             THEN '('               + CASE WHEN c.Max_Length = -1 THEN 'MAX'                ELSE CONVERT(VARCHAR(4),                    CASE WHEN t.Name IN ('nchar', 'nvarchar')                      THEN c.Max_Length / 2 ELSE c.Max_Length                    END)                END + ')'       WHEN t.name IN ('decimal', 'numeric')       THEN '(' + CONVERT(VARCHAR(4), c.precision) + ',' + CONVERT(VARCHAR(4), c.Scale) + ')'       ELSE ''      END + CASE WHEN c.is_rowguidcol = 1          THEN ' ROWGUIDCOL'          ELSE ''         END + CASE WHEN XML_collection_ID <> 0            THEN --deal with object schema names             '(' + CASE WHEN is_XML_Document = 1                THEN 'DOCUMENT '                ELSE 'CONTENT '               END + COALESCE((SELECT                QUOTENAME(ss.name) + '.' + QUOTENAME(sc.name)                FROM                sys.xml_schema_collections sc                INNER JOIN Sys.Schemas ss ON sc.schema_ID = ss.schema_ID                WHERE                sc.xml_collection_ID = c.XML_collection_ID),                'NULL') + ')'            ELSE ''           END + CASE WHEN is_identity = 1             THEN CASE WHEN OBJECTPROPERTY(object_id,                'IsUserTable') = 1 AND COLUMNPROPERTY(object_id,                c.name,                'IsIDNotForRepl') = 0 AND OBJECTPROPERTY(object_id,                'IsMSShipped') = 0                THEN ''                ELSE ' NOT FOR REPLICATION '               END             ELSE ''            END + CASE WHEN c.is_nullable = 0               THEN ' NOT NULL'               ELSE ' NULL'              END + CASE                WHEN c.default_object_id <> 0                THEN ' DEFAULT ' + object_Definition(c.default_object_id)                ELSE ''               END + CASE                WHEN c.collation_name IS NULL                THEN ''                WHEN c.collation_name <> (SELECT                collation_name                FROM                sys.databases                WHERE                name = DB_NAME()) COLLATE Latin1_General_CI_AS                THEN COALESCE(' COLLATE ' + c.collation_name,                '')                ELSE ''                END,'  ',' ') AS [DataType]FROM sys.columns c  INNER JOIN sys.types t ON c.user_Type_ID = t.user_Type_ID  WHERE OBJECT_SCHEMA_NAME(c.object_ID) <> 'sys')SELECT CONVERT(CHAR(80),objectName+'.'+columnName),DataType FROM UserColumnsWHERE columnName IN (SELECT columnName FROM UserColumns  GROUP BY columnName  HAVING MIN(Datatype)<>MAX(DataType))ORDER BY columnName If you take a look down the results against Adventureworks, you'll see once again that there are things to investigate, mostly, in the illustration, discrepancies between null and non-null datatypes So I here you ask, what about temporary variables within routines? If ever there was a source of elusive bugs, you'll find it there. Sadly, these temporary variables are not stored in the metadata so we'll have to find a more subtle way of flushing these out, and that will, I'm afraid, have to wait!

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  • Dynamically loading Assemblies to reduce Runtime Dependencies

    - by Rick Strahl
    I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change.  So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. This will change though depending on the size of objects serialized - the larger the object the more processing time is spent inside the actual dynamically activated components and the less difference there will be. Dynamic code is always slower, but how much it really affects your application primarily depends on how frequently the dynamic code is called in relation to the non-dynamic code executing. In most situations where dynamic code is used 'to get the process rolling' as I do here the overhead is small enough to not matter.All that being said though - I serialized 10,000 objects in 80ms vs. 45ms so this is hardly slouchy performance. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?Dynamic loading is not something you need to worry about but on occasion dynamic loading makes sense. But there's a price to be paid in added code  and a performance hit which depends on how frequently the dynamic code is accessed. But for some operations that are not pivotal to a component or application and are only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files adding dependencies and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems like a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful option in your toolset… © Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET  C#   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Informed TDD &ndash; Kata &ldquo;To Roman Numerals&rdquo;

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/05/28/informed-tdd-ndash-kata-ldquoto-roman-numeralsrdquo.aspxIn a comment on my article on what I call Informed TDD (ITDD) reader gustav asked how this approach would apply to the kata “To Roman Numerals”. And whether ITDD wasn´t a violation of TDD´s principle of leaving out “advanced topics like mocks”. I like to respond with this article to his questions. There´s more to say than fits into a commentary. Mocks and TDD I don´t see in how far TDD is avoiding or opposed to mocks. TDD and mocks are orthogonal. TDD is about pocess, mocks are about structure and costs. Maybe by moving forward in tiny red+green+refactor steps less need arises for mocks. But then… if the functionality you need to implement requires “expensive” resource access you can´t avoid using mocks. Because you don´t want to constantly run all your tests against the real resource. True, in ITDD mocks seem to be in almost inflationary use. That´s not what you usually see in TDD demonstrations. However, there´s a reason for that as I tried to explain. I don´t use mocks as proxies for “expensive” resource. Rather they are stand-ins for functionality not yet implemented. They allow me to get a test green on a high level of abstraction. That way I can move forward in a top-down fashion. But if you think of mocks as “advanced” or if you don´t want to use a tool like JustMock, then you don´t need to use mocks. You just need to stand the sight of red tests for a little longer ;-) Let me show you what I mean by that by doing a kata. ITDD for “To Roman Numerals” gustav asked for the kata “To Roman Numerals”. I won´t explain the requirements again. You can find descriptions and TDD demonstrations all over the internet, like this one from Corey Haines. Now here is, how I would do this kata differently. 1. Analyse A demonstration of TDD should never skip the analysis phase. It should be made explicit. The requirements should be formalized and acceptance test cases should be compiled. “Formalization” in this case to me means describing the API of the required functionality. “[D]esign a program to work with Roman numerals” like written in this “requirement document” is not enough to start software development. Coding should only begin, if the interface between the “system under development” and its context is clear. If this interface is not readily recognizable from the requirements, it has to be developed first. Exploration of interface alternatives might be in order. It might be necessary to show several interface mock-ups to the customer – even if that´s you fellow developer. Designing the interface is a task of it´s own. It should not be mixed with implementing the required functionality behind the interface. Unfortunately, though, this happens quite often in TDD demonstrations. TDD is used to explore the API and implement it at the same time. To me that´s a violation of the Single Responsibility Principle (SRP) which not only should hold for software functional units but also for tasks or activities. In the case of this kata the API fortunately is obvious. Just one function is needed: string ToRoman(int arabic). And it lives in a class ArabicRomanConversions. Now what about acceptance test cases? There are hardly any stated in the kata descriptions. Roman numerals are explained, but no specific test cases from the point of view of a customer. So I just “invent” some acceptance test cases by picking roman numerals from a wikipedia article. They are supposed to be just “typical examples” without special meaning. Given the acceptance test cases I then try to develop an understanding of the problem domain. I´ll spare you that. The domain is trivial and is explain in almost all kata descriptions. How roman numerals are built is not difficult to understand. What´s more difficult, though, might be to find an efficient solution to convert into them automatically. 2. Solve The usual TDD demonstration skips a solution finding phase. Like the interface exploration it´s mixed in with the implementation. But I don´t think this is how it should be done. I even think this is not how it really works for the people demonstrating TDD. They´re simplifying their true software development process because they want to show a streamlined TDD process. I doubt this is helping anybody. Before you code you better have a plan what to code. This does not mean you have to do “Big Design Up-Front”. It just means: Have a clear picture of the logical solution in your head before you start to build a physical solution (code). Evidently such a solution can only be as good as your understanding of the problem. If that´s limited your solution will be limited, too. Fortunately, in the case of this kata your understanding does not need to be limited. Thus the logical solution does not need to be limited or preliminary or tentative. That does not mean you need to know every line of code in advance. It just means you know the rough structure of your implementation beforehand. Because it should mirror the process described by the logical or conceptual solution. Here´s my solution approach: The arabic “encoding” of numbers represents them as an ordered set of powers of 10. Each digit is a factor to multiply a power of ten with. The “encoding” 123 is the short form for a set like this: {1*10^2, 2*10^1, 3*10^0}. And the number is the sum of the set members. The roman “encoding” is different. There is no base (like 10 for arabic numbers), there are just digits of different value, and they have to be written in descending order. The “encoding” XVI is short for [10, 5, 1]. And the number is still the sum of the members of this list. The roman “encoding” thus is simpler than the arabic. Each “digit” can be taken at face value. No multiplication with a base required. But what about IV which looks like a contradiction to the above rule? It is not – if you accept roman “digits” not to be limited to be single characters only. Usually I, V, X, L, C, D, M are viewed as “digits”, and IV, IX etc. are viewed as nuisances preventing a simple solution. All looks different, though, once IV, IX etc. are taken as “digits”. Then MCMLIV is just a sum: M+CM+L+IV which is 1000+900+50+4. Whereas before it would have been understood as M-C+M+L-I+V – which is more difficult because here some “digits” get subtracted. Here´s the list of roman “digits” with their values: {1, I}, {4, IV}, {5, V}, {9, IX}, {10, X}, {40, XL}, {50, L}, {90, XC}, {100, C}, {400, CD}, {500, D}, {900, CM}, {1000, M} Since I take IV, IX etc. as “digits” translating an arabic number becomes trivial. I just need to find the values of the roman “digits” making up the number, e.g. 1954 is made up of 1000, 900, 50, and 4. I call those “digits” factors. If I move from the highest factor (M=1000) to the lowest (I=1) then translation is a two phase process: Find all the factors Translate the factors found Compile the roman representation Translation is just a look-up. Finding, though, needs some calculation: Find the highest remaining factor fitting in the value Remember and subtract it from the value Repeat with remaining value and remaining factors Please note: This is just an algorithm. It´s not code, even though it might be close. Being so close to code in my solution approach is due to the triviality of the problem. In more realistic examples the conceptual solution would be on a higher level of abstraction. With this solution in hand I finally can do what TDD advocates: find and prioritize test cases. As I can see from the small process description above, there are two aspects to test: Test the translation Test the compilation Test finding the factors Testing the translation primarily means to check if the map of factors and digits is comprehensive. That´s simple, even though it might be tedious. Testing the compilation is trivial. Testing factor finding, though, is a tad more complicated. I can think of several steps: First check, if an arabic number equal to a factor is processed correctly (e.g. 1000=M). Then check if an arabic number consisting of two consecutive factors (e.g. 1900=[M,CM]) is processed correctly. Then check, if a number consisting of the same factor twice is processed correctly (e.g. 2000=[M,M]). Finally check, if an arabic number consisting of non-consecutive factors (e.g. 1400=[M,CD]) is processed correctly. I feel I can start an implementation now. If something becomes more complicated than expected I can slow down and repeat this process. 3. Implement First I write a test for the acceptance test cases. It´s red because there´s no implementation even of the API. That´s in conformance with “TDD lore”, I´d say: Next I implement the API: The acceptance test now is formally correct, but still red of course. This will not change even now that I zoom in. Because my goal is not to most quickly satisfy these tests, but to implement my solution in a stepwise manner. That I do by “faking” it: I just “assume” three functions to represent the transformation process of my solution: My hypothesis is that those three functions in conjunction produce correct results on the API-level. I just have to implement them correctly. That´s what I´m trying now – one by one. I start with a simple “detail function”: Translate(). And I start with all the test cases in the obvious equivalence partition: As you can see I dare to test a private method. Yes. That´s a white box test. But as you´ll see it won´t make my tests brittle. It serves a purpose right here and now: it lets me focus on getting one aspect of my solution right. Here´s the implementation to satisfy the test: It´s as simple as possible. Right how TDD wants me to do it: KISS. Now for the second equivalence partition: translating multiple factors. (It´a pattern: if you need to do something repeatedly separate the tests for doing it once and doing it multiple times.) In this partition I just need a single test case, I guess. Stepping up from a single translation to multiple translations is no rocket science: Usually I would have implemented the final code right away. Splitting it in two steps is just for “educational purposes” here. How small your implementation steps are is a matter of your programming competency. Some “see” the final code right away before their mental eye – others need to work their way towards it. Having two tests I find more important. Now for the next low hanging fruit: compilation. It´s even simpler than translation. A single test is enough, I guess. And normally I would not even have bothered to write that one, because the implementation is so simple. I don´t need to test .NET framework functionality. But again: if it serves the educational purpose… Finally the most complicated part of the solution: finding the factors. There are several equivalence partitions. But still I decide to write just a single test, since the structure of the test data is the same for all partitions: Again, I´m faking the implementation first: I focus on just the first test case. No looping yet. Faking lets me stay on a high level of abstraction. I can write down the implementation of the solution without bothering myself with details of how to actually accomplish the feat. That´s left for a drill down with a test of the fake function: There are two main equivalence partitions, I guess: either the first factor is appropriate or some next. The implementation seems easy. Both test cases are green. (Of course this only works on the premise that there´s always a matching factor. Which is the case since the smallest factor is 1.) And the first of the equivalence partitions on the higher level also is satisfied: Great, I can move on. Now for more than a single factor: Interestingly not just one test becomes green now, but all of them. Great! You might say, then I must have done not the simplest thing possible. And I would reply: I don´t care. I did the most obvious thing. But I also find this loop very simple. Even simpler than a recursion of which I had thought briefly during the problem solving phase. And by the way: Also the acceptance tests went green: Mission accomplished. At least functionality wise. Now I´ve to tidy up things a bit. TDD calls for refactoring. Not uch refactoring is needed, because I wrote the code in top-down fashion. I faked it until I made it. I endured red tests on higher levels while lower levels weren´t perfected yet. But this way I saved myself from refactoring tediousness. At the end, though, some refactoring is required. But maybe in a different way than you would expect. That´s why I rather call it “cleanup”. First I remove duplication. There are two places where factors are defined: in Translate() and in Find_factors(). So I factor the map out into a class constant. Which leads to a small conversion in Find_factors(): And now for the big cleanup: I remove all tests of private methods. They are scaffolding tests to me. They only have temporary value. They are brittle. Only acceptance tests need to remain. However, I carry over the single “digit” tests from Translate() to the acceptance test. I find them valuable to keep, since the other acceptance tests only exercise a subset of all roman “digits”. This then is my final test class: And this is the final production code: Test coverage as reported by NCrunch is 100%: Reflexion Is this the smallest possible code base for this kata? Sure not. You´ll find more concise solutions on the internet. But LOC are of relatively little concern – as long as I can understand the code quickly. So called “elegant” code, however, often is not easy to understand. The same goes for KISS code – especially if left unrefactored, as it is often the case. That´s why I progressed from requirements to final code the way I did. I first understood and solved the problem on a conceptual level. Then I implemented it top down according to my design. I also could have implemented it bottom-up, since I knew some bottom of the solution. That´s the leaves of the functional decomposition tree. Where things became fuzzy, since the design did not cover any more details as with Find_factors(), I repeated the process in the small, so to speak: fake some top level, endure red high level tests, while first solving a simpler problem. Using scaffolding tests (to be thrown away at the end) brought two advantages: Encapsulation of the implementation details was not compromised. Naturally private methods could stay private. I did not need to make them internal or public just to be able to test them. I was able to write focused tests for small aspects of the solution. No need to test everything through the solution root, the API. The bottom line thus for me is: Informed TDD produces cleaner code in a systematic way. It conforms to core principles of programming: Single Responsibility Principle and/or Separation of Concerns. Distinct roles in development – being a researcher, being an engineer, being a craftsman – are represented as different phases. First find what, what there is. Then devise a solution. Then code the solution, manifest the solution in code. Writing tests first is a good practice. But it should not be taken dogmatic. And above all it should not be overloaded with purposes. And finally: moving from top to bottom through a design produces refactored code right away. Clean code thus almost is inevitable – and not left to a refactoring step at the end which is skipped often for different reasons.   PS: Yes, I have done this kata several times. But that has only an impact on the time needed for phases 1 and 2. I won´t skip them because of that. And there are no shortcuts during implementation because of that.

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  • Using the jQuery UI Library in a MVC 3 Application to Build a Dialog Form

    - by ChrisD
    Using a simulated dialog window is a nice way to handle inline data editing. The jQuery UI has a UI widget for a dialog window that makes it easy to get up and running with it in your application. With the release of ASP.NET MVC 3, Microsoft included the jQuery UI scripts and files in the MVC 3 project templates for Visual Studio. With the release of the MVC 3 Tools Update, Microsoft implemented the inclusion of those with NuGet as packages. That means we can get up and running using the latest version of the jQuery UI with minimal effort. To the code! Another that might interested you about JQuery Mobile and ASP.NET MVC 3 with C#. If you are starting with a new MVC 3 application and have the Tools Update then you are a NuGet update and a <link> and <script> tag away from adding the jQuery UI to your project. If you are using an existing MVC project you can still get the jQuery UI library added to your project via NuGet and then add the link and script tags. Assuming that you have pulled down the latest version (at the time of this publish it was 1.8.13) you can add the following link and script tags to your <head> tag: < link href = "@Url.Content(" ~ / Content / themes / base / jquery . ui . all . css ")" rel = "Stylesheet" type = "text/css" /> < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > The jQuery UI library relies upon the CSS scripts and some image files to handle rendering of its widgets (you can choose a different theme or role your own if you like). Adding these to the stock _Layout.cshtml file results in the following markup: <!DOCTYPE html> < html > < head >     < meta charset = "utf-8" />     < title > @ViewBag.Title </ title >     < link href = "@Url.Content(" ~ / Content / Site . css ")" rel = "stylesheet" type = "text/css" />     <link href="@Url.Content("~/Content/themes/base/jquery.ui.all.css")" rel="Stylesheet" type="text/css" />     <script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" type="text/javascript"></script>     <script src="@Url.Content("~/Scripts/modernizr-1.7.min . js ")" type = "text/javascript" ></ script >     < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > </ head > < body >     @RenderBody() </ body > </ html > Our example will involve building a list of notes with an id, title and description. Each note can be edited and new notes can be added. The user will never have to leave the single page of notes to manage the note data. The add and edit forms will be delivered in a jQuery UI dialog widget and the note list content will get reloaded via an AJAX call after each change to the list. To begin, we need to craft a model and a data management class. We will do this so we can simulate data storage and get a feel for the workflow of the user experience. The first class named Note will have properties to represent our data model. namespace Website . Models {     public class Note     {         public int Id { get ; set ; }         public string Title { get ; set ; }         public string Body { get ; set ; }     } } The second class named NoteManager will be used to set up our simulated data storage and provide methods for querying and updating the data. We will take a look at the class content as a whole and then walk through each method after. using System . Collections . ObjectModel ; using System . Linq ; using System . Web ; namespace Website . Models {     public class NoteManager     {         public Collection < Note > Notes         {             get             {                 if ( HttpRuntime . Cache [ "Notes" ] == null )                     this . loadInitialData ();                 return ( Collection < Note >) HttpRuntime . Cache [ "Notes" ];             }         }         private void loadInitialData ()         {             var notes = new Collection < Note >();             notes . Add ( new Note                           {                               Id = 1 ,                               Title = "Set DVR for Sunday" ,                               Body = "Don't forget to record Game of Thrones!"                           });             notes . Add ( new Note                           {                               Id = 2 ,                               Title = "Read MVC article" ,                               Body = "Check out the new iwantmymvc.com post"                           });             notes . Add ( new Note                           {                               Id = 3 ,                               Title = "Pick up kid" ,                               Body = "Daughter out of school at 1:30pm on Thursday. Don't forget!"                           });             notes . Add ( new Note                           {                               Id = 4 ,                               Title = "Paint" ,                               Body = "Finish the 2nd coat in the bathroom"                           });             HttpRuntime . Cache [ "Notes" ] = notes ;         }         public Collection < Note > GetAll ()         {             return Notes ;         }         public Note GetById ( int id )         {             return Notes . Where ( i => i . Id == id ). FirstOrDefault ();         }         public int Save ( Note item )         {             if ( item . Id <= 0 )                 return saveAsNew ( item );             var existingNote = Notes . Where ( i => i . Id == item . Id ). FirstOrDefault ();             existingNote . Title = item . Title ;             existingNote . Body = item . Body ;             return existingNote . Id ;         }         private int saveAsNew ( Note item )         {             item . Id = Notes . Count + 1 ;             Notes . Add ( item );             return item . Id ;         }     } } The class has a property named Notes that is read only and handles instantiating a collection of Note objects in the runtime cache if it doesn't exist, and then returns the collection from the cache. This property is there to give us a simulated storage so that we didn't have to add a full blown database (beyond the scope of this post). The private method loadInitialData handles pre-filling the collection of Note objects with some initial data and stuffs them into the cache. Both of these chunks of code would be refactored out with a move to a real means of data storage. The GetAll and GetById methods access our simulated data storage to return all of our notes or a specific note by id. The Save method takes in a Note object, checks to see if it has an Id less than or equal to zero (we assume that an Id that is not greater than zero represents a note that is new) and if so, calls the private method saveAsNew . If the Note item sent in has an Id , the code finds that Note in the simulated storage, updates the Title and Description , and returns the Id value. The saveAsNew method sets the Id , adds it to the simulated storage, and returns the Id value. The increment of the Id is simulated here by getting the current count of the note collection and adding 1 to it. The setting of the Id is the only other chunk of code that would be refactored out when moving to a different data storage approach. With our model and data manager code in place we can turn our attention to the controller and views. We can do all of our work in a single controller. If we use a HomeController , we can add an action method named Index that will return our main view. An action method named List will get all of our Note objects from our manager and return a partial view. We will use some jQuery to make an AJAX call to that action method and update our main view with the partial view content returned. Since the jQuery AJAX call will cache the call to the content in Internet Explorer by default (a setting in jQuery), we will decorate the List, Create and Edit action methods with the OutputCache attribute and a duration of 0. This will send the no-cache flag back in the header of the content to the browser and jQuery will pick that up and not cache the AJAX call. The Create action method instantiates a new Note model object and returns a partial view, specifying the NoteForm.cshtml view file and passing in the model. The NoteForm view is used for the add and edit functionality. The Edit action method takes in the Id of the note to be edited, loads the Note model object based on that Id , and does the same return of the partial view as the Create method. The Save method takes in the posted Note object and sends it to the manager to save. It is decorated with the HttpPost attribute to ensure that it will only be available via a POST. It returns a Json object with a property named Success that can be used by the UX to verify everything went well (we won't use that in our example). Both the add and edit actions in the UX will post to the Save action method, allowing us to reduce the amount of unique jQuery we need to write in our view. The contents of the HomeController.cs file: using System . Web . Mvc ; using Website . Models ; namespace Website . Controllers {     public class HomeController : Controller     {         public ActionResult Index ()         {             return View ();         }         [ OutputCache ( Duration = 0 )]         public ActionResult List ()         {             var manager = new NoteManager ();             var model = manager . GetAll ();             return PartialView ( model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Create ()         {             var model = new Note ();             return PartialView ( "NoteForm" , model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Edit ( int id )         {             var manager = new NoteManager ();             var model = manager . GetById ( id );             return PartialView ( "NoteForm" , model );         }         [ HttpPost ]         public JsonResult Save ( Note note )         {             var manager = new NoteManager ();             var noteId = manager . Save ( note );             return Json ( new { Success = noteId > 0 });         }     } } The view for the note form, NoteForm.cshtml , looks like so: @model Website . Models . Note @using ( Html . BeginForm ( "Save" , "Home" , FormMethod . Post , new { id = "NoteForm" })) { @Html . Hidden ( "Id" ) < label class = "Title" >     < span > Title < /span><br / >     @Html . TextBox ( "Title" ) < /label> <label class="Body">     <span>Body</ span >< br />     @Html . TextArea ( "Body" ) < /label> } It is a strongly typed view for our Note model class. We give the <form> element an id attribute so that we can reference it via jQuery. The <label> and <span> tags give our UX some structure that we can style with some CSS. The List.cshtml view is used to render out a <ul> element with all of our notes. @model IEnumerable < Website . Models . Note > < ul class = "NotesList" >     @foreach ( var note in Model )     {     < li >         @note . Title < br />         @note . Body < br />         < span class = "EditLink ButtonLink" noteid = "@note.Id" > Edit < /span>     </ li >     } < /ul> This view is strongly typed as well. It includes a <span> tag that we will use as an edit button. We add a custom attribute named noteid to the <span> tag that we can use in our jQuery to identify the Id of the note object we want to edit. The view, Index.cshtml , contains a bit of html block structure and all of our jQuery logic code. @ {     ViewBag . Title = "Index" ; } < h2 > Notes < /h2> <div id="NoteListBlock"></ div > < span class = "AddLink ButtonLink" > Add New Note < /span> <div id="NoteDialog" title="" class="Hidden"></ div > < script type = "text/javascript" >     $ ( function () {         $ ( "#NoteDialog" ). dialog ({             autoOpen : false , width : 400 , height : 330 , modal : true ,             buttons : {                 "Save" : function () {                     $ . post ( "/Home/Save" ,                         $ ( "#NoteForm" ). serialize (),                         function () {                             $ ( "#NoteDialog" ). dialog ( "close" );                             LoadList ();                         });                 },                 Cancel : function () { $ ( this ). dialog ( "close" ); }             }         });         $ ( ".EditLink" ). live ( "click" , function () {             var id = $ ( this ). attr ( "noteid" );             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Edit Note" )                 . load ( "/Home/Edit/" + id , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         $ ( ".AddLink" ). click ( function () {             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Add Note" )                 . load ( "/Home/Create" , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         LoadList ();     });     function LoadList () {         $ ( "#NoteListBlock" ). load ( "/Home/List" );     } < /script> The <div> tag with the id attribute of "NoteListBlock" is used as a container target for the load of the partial view content of our List action method. It starts out empty and will get loaded with content via jQuery once the DOM is loaded. The <div> tag with the id attribute of "NoteDialog" is the element for our dialog widget. The jQuery UI library will use the title attribute for the text in the dialog widget top header bar. We start out with it empty here and will dynamically change the text via jQuery based on the request to either add or edit a note. This <div> tag is given a CSS class named "Hidden" that will set the display:none style on the element. Since our call to the jQuery UI method to make the element a dialog widget will occur in the jQuery document ready code block, the end user will see the <div> element rendered in their browser as the page renders and then it will hide after that jQuery call. Adding the display:hidden to the <div> element via CSS will ensure that it is never rendered until the user triggers the request to open the dialog. The jQuery document load block contains the setup for the dialog node, click event bindings for the edit and add links, and a call to a JavaScript function called LoadList that handles the AJAX call to the List action method. The .dialog() method is called on the "NoteDialog" <div> element and the options are set for the dialog widget. The buttons option defines 2 buttons and their click actions. The first is the "Save" button (the text in quotations is used as the text for the button) that will do an AJAX post to our Save action method and send the serialized form data from the note form (targeted with the id attribute "NoteForm"). Upon completion it will close the dialog widget and call the LoadList to update the UX without a redirect. The "Cancel" button simply closes the dialog widget. The .live() method handles binding a function to the "click" event on all elements with the CSS class named EditLink . We use the .live() method because it will catch and bind our function to elements even as the DOM changes. Since we will be constantly changing the note list as we add and edit we want to ensure that the edit links get wired up with click events. The function for the click event on the edit links gets the noteid attribute and stores it in a local variable. Then it clears out the HTML in the dialog element (to ensure a fresh start), calls the .dialog() method and sets the "title" option (this sets the title attribute value), and then calls the .load() AJAX method to hit our Edit action method and inject the returned content into the "NoteDialog" <div> element. Once the .load() method is complete it opens the dialog widget. The click event binding for the add link is similar to the edit, only we don't need to get the id value and we load the Create action method. This binding is done via the .click() method because it will only be bound on the initial load of the page. The add button will always exist. Finally, we toss in some CSS in the Content/Site.css file to style our form and the add/edit links. . ButtonLink { color : Blue ; cursor : pointer ; } . ButtonLink : hover { text - decoration : underline ; } . Hidden { display : none ; } #NoteForm label { display:block; margin-bottom:6px; } #NoteForm label > span { font-weight:bold; } #NoteForm input[type=text] { width:350px; } #NoteForm textarea { width:350px; height:80px; } With all of our code in place we can do an F5 and see our list of notes: If we click on an edit link we will get the dialog widget with the correct note data loaded: And if we click on the add new note link we will get the dialog widget with the empty form: The end result of our solution tree for our sample:

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  • Diving into OpenStack Network Architecture - Part 2 - Basic Use Cases

    - by Ronen Kofman
      rkofman Normal rkofman 4 138 2014-06-05T03:38:00Z 2014-06-05T05:04:00Z 3 2735 15596 Oracle Corporation 129 36 18295 12.00 Clean Clean false false false false EN-US X-NONE HE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi; mso-bidi-language:AR-SA;} In the previous post we reviewed several network components including Open vSwitch, Network Namespaces, Linux Bridges and veth pairs. In this post we will take three simple use cases and see how those basic components come together to create a complete SDN solution in OpenStack. With those three use cases we will review almost the entire network setup and see how all the pieces work together. The use cases we will use are: 1.       Create network – what happens when we create network and how can we create multiple isolated networks 2.       Launch a VM – once we have networks we can launch VMs and connect them to networks. 3.       DHCP request from a VM – OpenStack can automatically assign IP addresses to VMs. This is done through local DHCP service controlled by OpenStack Neutron. We will see how this service runs and how does a DHCP request and response look like. In this post we will show connectivity, we will see how packets get from point A to point B. We first focus on how a configured deployment looks like and only later we will discuss how and when the configuration is created. Personally I found it very valuable to see the actual interfaces and how they connect to each other through examples and hands on experiments. After the end game is clear and we know how the connectivity works, in a later post, we will take a step back and explain how Neutron configures the components to be able to provide such connectivity.  We are going to get pretty technical shortly and I recommend trying these examples on your own deployment or using the Oracle OpenStack Tech Preview. Understanding these three use cases thoroughly and how to look at them will be very helpful when trying to debug a deployment in case something does not work. Use case #1: Create Network Create network is a simple operation it can be performed from the GUI or command line. When we create a network in OpenStack the network is only available to the tenant who created it or it could be defined as “shared” and then it can be used by all tenants. A network can have multiple subnets but for this demonstration purpose and for simplicity we will assume that each network has exactly one subnet. Creating a network from the command line will look like this: # neutron net-create net1 Created a new network: +---------------------------+--------------------------------------+ | Field                     | Value                                | +---------------------------+--------------------------------------+ | admin_state_up            | True                                 | | id                        | 5f833617-6179-4797-b7c0-7d420d84040c | | name                      | net1                                 | | provider:network_type     | vlan                                 | | provider:physical_network | default                              | | provider:segmentation_id  | 1000                                 | | shared                    | False                                | | status                    | ACTIVE                               | | subnets                   |                                      | | tenant_id                 | 9796e5145ee546508939cd49ad59d51f     | +---------------------------+--------------------------------------+ Creating a subnet for this network will look like this: # neutron subnet-create net1 10.10.10.0/24 Created a new subnet: +------------------+------------------------------------------------+ | Field            | Value                                          | +------------------+------------------------------------------------+ | allocation_pools | {"start": "10.10.10.2", "end": "10.10.10.254"} | | cidr             | 10.10.10.0/24                                  | | dns_nameservers  |                                                | | enable_dhcp      | True                                           | | gateway_ip       | 10.10.10.1                                     | | host_routes      |                                                | | id               | 2d7a0a58-0674-439a-ad23-d6471aaae9bc           | | ip_version       | 4                                              | | name             |                                                | | network_id       | 5f833617-6179-4797-b7c0-7d420d84040c           | | tenant_id        | 9796e5145ee546508939cd49ad59d51f               | +------------------+------------------------------------------------+ We now have a network and a subnet, on the network topology view this looks like this: Now let’s dive in and see what happened under the hood. Looking at the control node we will discover that a new namespace was created: # ip netns list qdhcp-5f833617-6179-4797-b7c0-7d420d84040c   The name of the namespace is qdhcp-<network id> (see above), let’s look into the namespace and see what’s in it: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00     inet 127.0.0.1/8 scope host lo     inet6 ::1/128 scope host        valid_lft forever preferred_lft forever 12: tap26c9b807-7c: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN     link/ether fa:16:3e:1d:5c:81 brd ff:ff:ff:ff:ff:ff     inet 10.10.10.3/24 brd 10.10.10.255 scope global tap26c9b807-7c     inet6 fe80::f816:3eff:fe1d:5c81/64 scope link        valid_lft forever preferred_lft forever   We see two interfaces in the namespace, one is the loopback and the other one is an interface called “tap26c9b807-7c”. This interface has the IP address of 10.10.10.3 and it will also serve dhcp requests in a way we will see later. Let’s trace the connectivity of the “tap26c9b807-7c” interface from the namespace.  First stop is OVS, we see that the interface connects to bridge  “br-int” on OVS: # ovs-vsctl show 8a069c7c-ea05-4375-93e2-b9fc9e4b3ca1     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-ex         Port br-ex             Interface br-ex                 type: internal     Bridge br-int         Port "int-br-eth2"             Interface "int-br-eth2"         Port "tap26c9b807-7c"             tag: 1             Interface "tap26c9b807-7c"                 type: internal         Port br-int             Interface br-int                 type: internal     ovs_version: "1.11.0"   In the picture above we have a veth pair which has two ends called “int-br-eth2” and "phy-br-eth2", this veth pair is used to connect two bridge in OVS "br-eth2" and "br-int". In the previous post we explained how to check the veth connectivity using the ethtool command. It shows that the two are indeed a pair: # ethtool -S int-br-eth2 NIC statistics:      peer_ifindex: 10 . .   #ip link . . 10: phy-br-eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 . . Note that “phy-br-eth2” is connected to a bridge called "br-eth2" and one of this bridge's interfaces is the physical link eth2. This means that the network which we have just created has created a namespace which is connected to the physical interface eth2. eth2 is the “VM network” the physical interface where all the virtual machines connect to where all the VMs are connected. About network isolation: OpenStack supports creation of multiple isolated networks and can use several mechanisms to isolate the networks from one another. The isolation mechanism can be VLANs, VxLANs or GRE tunnels, this is configured as part of the initial setup in our deployment we use VLANs. When using VLAN tagging as an isolation mechanism a VLAN tag is allocated by Neutron from a pre-defined VLAN tags pool and assigned to the newly created network. By provisioning VLAN tags to the networks Neutron allows creation of multiple isolated networks on the same physical link.  The big difference between this and other platforms is that the user does not have to deal with allocating and managing VLANs to networks. The VLAN allocation and provisioning is handled by Neutron which keeps track of the VLAN tags, and responsible for allocating and reclaiming VLAN tags. In the example above net1 has the VLAN tag 1000, this means that whenever a VM is created and connected to this network the packets from that VM will have to be tagged with VLAN tag 1000 to go on this particular network. This is true for namespace as well, if we would like to connect a namespace to a particular network we have to make sure that the packets to and from the namespace are correctly tagged when they reach the VM network. In the example above we see that the namespace interface “tap26c9b807-7c” has vlan tag 1 assigned to it, if we examine OVS we see that it has flows which modify VLAN tag 1 to VLAN tag 1000 when a packet goes to the VM network on eth2 and vice versa. We can see this using the dump-flows command on OVS for packets going to the VM network we see the modification done on br-eth2: #  ovs-ofctl dump-flows br-eth2 NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18669.401s, table=0, n_packets=857, n_bytes=163350, idle_age=25, priority=4,in_port=2,dl_vlan=1 actions=mod_vlan_vid:1000,NORMAL  cookie=0x0, duration=165108.226s, table=0, n_packets=14, n_bytes=1000, idle_age=5343, hard_age=65534, priority=2,in_port=2 actions=drop  cookie=0x0, duration=165109.813s, table=0, n_packets=1671, n_bytes=213304, idle_age=25, hard_age=65534, priority=1 actions=NORMAL   For packets coming from the interface to the namespace we see the following modification: #  ovs-ofctl dump-flows br-int NXST_FLOW reply (xid=0x4):  cookie=0x0, duration=18690.876s, table=0, n_packets=1610, n_bytes=210752, idle_age=1, priority=3,in_port=1,dl_vlan=1000 actions=mod_vlan_vid:1,NORMAL  cookie=0x0, duration=165130.01s, table=0, n_packets=75, n_bytes=3686, idle_age=4212, hard_age=65534, priority=2,in_port=1 actions=drop  cookie=0x0, duration=165131.96s, table=0, n_packets=863, n_bytes=160727, idle_age=1, hard_age=65534, priority=1 actions=NORMAL   To summarize we can see that when a user creates a network Neutron creates a namespace and this namespace is connected through OVS to the “VM network”. OVS also takes care of tagging the packets from the namespace to the VM network with the correct VLAN tag and knows to modify the VLAN for packets coming from VM network to the namespace. Now let’s see what happens when a VM is launched and how it is connected to the “VM network”. Use case #2: Launch a VM Launching a VM can be done from Horizon or from the command line this is how we do it from Horizon: Attach the network: And Launch Once the virtual machine is up and running we can see the associated IP using the nova list command : # nova list +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | ID                                   | Name         | Status | Task State | Power State | Networks        | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ | 3707ac87-4f5d-4349-b7ed-3a673f55e5e1 | Oracle Linux | ACTIVE | None       | Running     | net1=10.10.10.2 | +--------------------------------------+--------------+--------+------------+-------------+-----------------+ The nova list command shows us that the VM is running and that the IP 10.10.10.2 is assigned to this VM. Let’s trace the connectivity from the VM to VM network on eth2 starting with the VM definition file. The configuration files of the VM including the virtual disk(s), in case of ephemeral storage, are stored on the compute node at/var/lib/nova/instances/<instance-id>/. Looking into the VM definition file ,libvirt.xml,  we see that the VM is connected to an interface called “tap53903a95-82” which is connected to a Linux bridge called “qbr53903a95-82”: <interface type="bridge">       <mac address="fa:16:3e:fe:c7:87"/>       <source bridge="qbr53903a95-82"/>       <target dev="tap53903a95-82"/>     </interface>   Looking at the bridge using the brctl show command we see this: # brctl show bridge name     bridge id               STP enabled     interfaces qbr53903a95-82          8000.7e7f3282b836       no              qvb53903a95-82                                                         tap53903a95-82    The bridge has two interfaces, one connected to the VM (“tap53903a95-82 “) and another one ( “qvb53903a95-82”) connected to “br-int” bridge on OVS: # ovs-vsctl show 83c42f80-77e9-46c8-8560-7697d76de51c     Bridge "br-eth2"         Port "br-eth2"             Interface "br-eth2"                 type: internal         Port "eth2"             Interface "eth2"         Port "phy-br-eth2"             Interface "phy-br-eth2"     Bridge br-int         Port br-int             Interface br-int                 type: internal         Port "int-br-eth2"             Interface "int-br-eth2"         Port "qvo53903a95-82"             tag: 3             Interface "qvo53903a95-82"     ovs_version: "1.11.0"   As we showed earlier “br-int” is connected to “br-eth2” on OVS using the veth pair int-br-eth2,phy-br-eth2 and br-eth2 is connected to the physical interface eth2. The whole flow end to end looks like this: VM è tap53903a95-82 (virtual interface)è qbr53903a95-82 (Linux bridge) è qvb53903a95-82 (interface connected from Linux bridge to OVS bridge br-int) è int-br-eth2 (veth one end) è phy-br-eth2 (veth the other end) è eth2 physical interface. The purpose of the Linux Bridge connecting to the VM is to allow security group enforcement with iptables. Security groups are enforced at the edge point which are the interface of the VM, since iptables nnot be applied to OVS bridges we use Linux bridge to apply them. In the future we hope to see this Linux Bridge going away rules.  VLAN tags: As we discussed in the first use case net1 is using VLAN tag 1000, looking at OVS above we see that qvo41f1ebcf-7c is tagged with VLAN tag 3. The modification from VLAN tag 3 to 1000 as we go to the physical network is done by OVS  as part of the packet flow of br-eth2 in the same way we showed before. To summarize, when a VM is launched it is connected to the VM network through a chain of elements as described here. During the packet from VM to the network and back the VLAN tag is modified. Use case #3: Serving a DHCP request coming from the virtual machine In the previous use cases we have shown that both the namespace called dhcp-<some id> and the VM end up connecting to the physical interface eth2  on their respective nodes, both will tag their packets with VLAN tag 1000.We saw that the namespace has an interface with IP of 10.10.10.3. Since the VM and the namespace are connected to each other and have interfaces on the same subnet they can ping each other, in this picture we see a ping from the VM which was assigned 10.10.10.2 to the namespace: The fact that they are connected and can ping each other can become very handy when something doesn’t work right and we need to isolate the problem. In such case knowing that we should be able to ping from the VM to the namespace and back can be used to trace the disconnect using tcpdump or other monitoring tools. To serve DHCP requests coming from VMs on the network Neutron uses a Linux tool called “dnsmasq”,this is a lightweight DNS and DHCP service you can read more about it here. If we look at the dnsmasq on the control node with the ps command we see this: dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap26c9b807-7c --except-interface=lo --pid-file=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host --dhcp-optsfile=/var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/opts --leasefile-ro --dhcp-range=tag0,10.10.10.0,static,120s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal The service connects to the tap interface in the namespace (“--interface=tap26c9b807-7c”), If we look at the hosts file we see this: # cat  /var/lib/neutron/dhcp/5f833617-6179-4797-b7c0-7d420d84040c/host fa:16:3e:fe:c7:87,host-10-10-10-2.openstacklocal,10.10.10.2   If you look at the console output above you can see the MAC address fa:16:3e:fe:c7:87 which is the VM MAC. This MAC address is mapped to IP 10.10.10.2 and so when a DHCP request comes with this MAC dnsmasq will return the 10.10.10.2.If we look into the namespace at the time we initiate a DHCP request from the VM (this can be done by simply restarting the network service in the VM) we see the following: # ip netns exec qdhcp-5f833617-6179-4797-b7c0-7d420d84040c tcpdump -n 19:27:12.191280 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:fe:c7:87, length 310 19:27:12.191666 IP 10.10.10.3.bootps > 10.10.10.2.bootpc: BOOTP/DHCP, Reply, length 325   To summarize, the DHCP service is handled by dnsmasq which is configured by Neutron to listen to the interface in the DHCP namespace. Neutron also configures dnsmasq with the combination of MAC and IP so when a DHCP request comes along it will receive the assigned IP. Summary In this post we relied on the components described in the previous post and saw how network connectivity is achieved using three simple use cases. These use cases gave a good view of the entire network stack and helped understand how an end to end connection is being made between a VM on a compute node and the DHCP namespace on the control node. One conclusion we can draw from what we saw here is that if we launch a VM and it is able to perform a DHCP request and receive a correct IP then there is reason to believe that the network is working as expected. We saw that a packet has to travel through a long list of components before reaching its destination and if it has done so successfully this means that many components are functioning properly. In the next post we will look at some more sophisticated services Neutron supports and see how they work. We will see that while there are some more components involved for the most part the concepts are the same. @RonenKofman

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  • Internal Server Error with mod_wsgi [django] on windows xp

    - by sacabuche
    when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order allow,deny Allow from all </Directory> Alias /codevents/media C:/django/projects/CODEvents/html <Directory "C:/django/projects/CODEvents/html"> Order allow,deny Allow from all </Directory> in CODEvents.wsgi import os, sys sys.path.append('C:\\Python26\\Lib\\site-packages\\django') sys.path.append('C:\\django\\projects') sys.path.append('C:\\django\\apps') sys.path.append('C:\\django\\projects\\CODEvents') os.environ['DJANGO_SETTINGS_MODULE'] = 'CODEvents.settings' import django.core.handlers.wsgi application = django.core.handlers.wsgi.WSGIHandler() and in my error_log it said: [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] mod_wsgi (pid=1848): Exception occurred processing WSGI script 'C:/django/apache/CODEvents.wsgi'. [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Traceback (most recent call last): [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\wsgi.py", line 241, in __call__ [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] response = self.get_response(request) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\base.py", line 142, in get_response [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.handle_uncaught_exception(request, resolver, exc_info) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\base.py", line 166, in handle_uncaught_exception [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return debug.technical_500_response(request, *exc_info) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\views\\debug.py", line 58, in technical_500_response [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] html = reporter.get_traceback_html() [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\views\\debug.py", line 137, in get_traceback_html [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return t.render(c) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 173, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self._render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 167, in _render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.nodelist.render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 796, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] bits.append(self.render_node(node, context)) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\debug.py", line 72, in render_node [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] result = node.render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\debug.py", line 89, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] output = self.filter_expression.resolve(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 579, in resolve [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] new_obj = func(obj, *arg_vals) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\defaultfilters.py", line 693, in date [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return format(value, arg) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 281, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return df.format(format_string) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 30, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] pieces.append(force_unicode(getattr(self, piece)())) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 187, in r [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.format('D, j M Y H:i:s O') [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 30, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] pieces.append(force_unicode(getattr(self, piece)())) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\encoding.py", line 66, in force_unicode [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] s = unicode(s) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\functional.py", line 206, in __unicode_cast [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.__func(*self.__args, **self.__kw) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\__init__.py", line 55, in ugettext [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return real_ugettext(message) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\functional.py", line 55, in _curried [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs)) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\__init__.py", line 36, in delayed_loader [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return getattr(trans, real_name)(*args, **kwargs) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 276, in ugettext [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return do_translate(message, 'ugettext') [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 266, in do_translate [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] _default = translation(settings.LANGUAGE_CODE) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 176, in translation [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] default_translation = _fetch(settings.LANGUAGE_CODE) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 159, in _fetch [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] app = import_module(appname) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\importlib.py", line 35, in import_module [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] __import__(name) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\contrib\\admin\\__init__.py", line 1, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django.contrib.admin.helpers import ACTION_CHECKBOX_NAME [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\contrib\\admin\\helpers.py", line 1, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django import forms [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\forms\\__init__.py", line 17, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from models import * [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\forms\\models.py", line 6, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django.db import connections [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\__init__.py", line 75, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] connection = connections[DEFAULT_DB_ALIAS] [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\utils.py", line 91, in __getitem__ [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] backend = load_backend(db['ENGINE']) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\utils.py", line 49, in load_backend [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] raise ImproperlyConfigured(error_msg) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] TemplateSyntaxError: Caught ImproperlyConfigured while rendering: 'django.db.backends.postgresql_psycopg2' isn't an available database backend. [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Try using django.db.backends.XXX, where XXX is one of: [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] 'dummy', 'mysql', 'oracle', 'postgresql', 'postgresql_psycopg2', 'sqlite3' [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Error was: cannot import name utils please help me!!

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  • Internal Server Error with mod_wgsi [django] on windows xp

    - by sacabuche
    when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order allow,deny Allow from all </Directory> Alias /codevents/media C:/django/projects/CODEvents/html <Directory "C:/django/projects/CODEvents/html"> Order allow,deny Allow from all </Directory> in CODEvents.wsgi import os, sys sys.path.append('C:\\Python26\\Lib\\site-packages\\django') sys.path.append('C:\\django\\projects') sys.path.append('C:\\django\\apps') sys.path.append('C:\\django\\projects\\CODEvents') os.environ['DJANGO_SETTINGS_MODULE'] = 'CODEvents.settings' import django.core.handlers.wsgi application = django.core.handlers.wsgi.WSGIHandler() and in my error_log it said: [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] mod_wsgi (pid=1848): Exception occurred processing WSGI script 'C:/django/apache/CODEvents.wsgi'. [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Traceback (most recent call last): [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\wsgi.py", line 241, in __call__ [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] response = self.get_response(request) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\base.py", line 142, in get_response [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.handle_uncaught_exception(request, resolver, exc_info) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\core\\handlers\\base.py", line 166, in handle_uncaught_exception [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return debug.technical_500_response(request, *exc_info) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\views\\debug.py", line 58, in technical_500_response [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] html = reporter.get_traceback_html() [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\views\\debug.py", line 137, in get_traceback_html [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return t.render(c) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 173, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self._render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 167, in _render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.nodelist.render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 796, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] bits.append(self.render_node(node, context)) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\debug.py", line 72, in render_node [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] result = node.render(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\debug.py", line 89, in render [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] output = self.filter_expression.resolve(context) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\__init__.py", line 579, in resolve [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] new_obj = func(obj, *arg_vals) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\template\\defaultfilters.py", line 693, in date [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return format(value, arg) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 281, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return df.format(format_string) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 30, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] pieces.append(force_unicode(getattr(self, piece)())) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 187, in r [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.format('D, j M Y H:i:s O') [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\dateformat.py", line 30, in format [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] pieces.append(force_unicode(getattr(self, piece)())) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\encoding.py", line 66, in force_unicode [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] s = unicode(s) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\functional.py", line 206, in __unicode_cast [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return self.__func(*self.__args, **self.__kw) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\__init__.py", line 55, in ugettext [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return real_ugettext(message) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\functional.py", line 55, in _curried [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs)) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\__init__.py", line 36, in delayed_loader [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return getattr(trans, real_name)(*args, **kwargs) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 276, in ugettext [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] return do_translate(message, 'ugettext') [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 266, in do_translate [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] _default = translation(settings.LANGUAGE_CODE) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 176, in translation [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] default_translation = _fetch(settings.LANGUAGE_CODE) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\translation\\trans_real.py", line 159, in _fetch [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] app = import_module(appname) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\utils\\importlib.py", line 35, in import_module [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] __import__(name) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\contrib\\admin\\__init__.py", line 1, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django.contrib.admin.helpers import ACTION_CHECKBOX_NAME [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\contrib\\admin\\helpers.py", line 1, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django import forms [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\forms\\__init__.py", line 17, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from models import * [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\forms\\models.py", line 6, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] from django.db import connections [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\__init__.py", line 75, in <module> [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] connection = connections[DEFAULT_DB_ALIAS] [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\utils.py", line 91, in __getitem__ [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] backend = load_backend(db['ENGINE']) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] File "C:\\Python26\\lib\\site-packages\\django\\db\\utils.py", line 49, in load_backend [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] raise ImproperlyConfigured(error_msg) [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] TemplateSyntaxError: Caught ImproperlyConfigured while rendering: 'django.db.backends.postgresql_psycopg2' isn't an available database backend. [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Try using django.db.backends.XXX, where XXX is one of: [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] 'dummy', 'mysql', 'oracle', 'postgresql', 'postgresql_psycopg2', 'sqlite3' [Mon May 24 23:31:39 2010] [error] [client 127.0.0.1] Error was: cannot import name utils please help me!!

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  • Ruby on Rails: url_for :back leads to NoMethodError for back_url

    - by Platinum Azure
    Hi all, I'm trying to use url_for(:back) to create a redirect leading back to a previous page upon a user's logging in. I've had it working successfully for when the user just goes to the login page on his or her own. However, when the user is redirected to the login page due to accessing a page requiring that the user be authenticated, the redirect sends the user back to the page before the one s/he had tried to access with insufficient permissions. I'm trying to modify my login controller action to deal with the redirect properly. My plan is to have a query string parameter "redirect" that is used when a forced redirect occurs. In the controller, if that parameter exists that URL is used; otherwise, url_for(:back) is used, or if that doesn't work (due to lack of HTTP_REFERER), then the user is redirected to the site's home page. Here is the code snippet which is supposed to implement this logic: if params[:redirect] @url = params[:redirect] else @url = url_for :back @url ||= url_for :controller => "home", :action => "index" end The error I get is: NoMethodError in UsersController#login undefined method `back_url' for # RAILS_ROOT: [obscured] Application Trace | Framework Trace | Full Trace vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' app/controllers/users_controller.rb:16:in `login' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' vendor/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action' vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache' vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support' vendor/rails/actionpack/lib/action_controller/session_management.rb:134:in `process' vendor/rails/actionpack/lib/action_controller/base.rb:392:in `process' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `synchronize' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/railties/lib/commands/servers/mongrel.rb:64 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/railties/lib/commands/server.rb:49 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' app/controllers/users_controller.rb:16:in `login' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' vendor/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action' vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache' vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support' vendor/rails/actionpack/lib/action_controller/session_management.rb:134:in `process' vendor/rails/actionpack/lib/action_controller/base.rb:392:in `process' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `synchronize' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/railties/lib/commands/servers/mongrel.rb:64 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/railties/lib/commands/server.rb:49 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 Request Parameters: None Show session dump --- :user: :csrf_id: 2927cca61bbbe97218362b5bcdb74c0f flash: !map:ActionController::Flash::FlashHash {} Response Headers: {"Content-Type"="", "cookie"=[], "Cache-Control"="no-cache"} Bear in mind that I had it working earlier-- url_for(:back) knew how to operate properly before I added this logic. Thanks in advance for any ideas!

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  • How to programmatically create customcontrol and change its values in Silverlight 4

    - by user361317
    Hi! I want to create a custom tabcontrol class which has an icon before the text, and I want to be able to change the icon in the constructor of the new tabcontrol. I use implicit styles in Silverlight 4, and the custom tabcontrol should not have any xaml of its own, just the class and the implicit xaml style in my App.xaml. I cannot, however, get this to work. This is my code: <!-- Style for generic tabcontrols --> 20,0,0,0 <Style TargetType="controls:TabItem"> <Setter Property="IsTabStop" Value="False"/> <Setter Property="Background" Value="#FFDBEDFB"/> <Setter Property="BorderBrush" Value="#FFA3AEB9"/> <Setter Property="BorderThickness" Value="1"/> <Setter Property="Padding" Value="6,2,6,2"/> <Setter Property="HorizontalContentAlignment" Value="Stretch"/> <Setter Property="VerticalContentAlignment" Value="Stretch"/> <Setter Property="MinWidth" Value="5"/> <Setter Property="MinHeight" Value="5"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="controls:TabItem"> <Grid x:Name="Root" Cursor="Hand" Height="25"> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="CommonStates"> <VisualStateGroup.Transitions> <VisualTransition GeneratedDuration="0"/> <VisualTransition GeneratedDuration="0:0:0.1" To="MouseOver"/> </VisualStateGroup.Transitions> <VisualState x:Name="Normal"/> <VisualState x:Name="MouseOver"> <Storyboard> <DoubleAnimationUsingKeyFrames BeginTime="0" Duration="00:00:00.001" Storyboard.TargetName="FocusVisualTop" Storyboard.TargetProperty="(UIElement.Opacity)"> <SplineDoubleKeyFrame KeyTime="0" Value="0"/> </DoubleAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="Disabled"> <Storyboard> <DoubleAnimationUsingKeyFrames Storyboard.TargetName="DisabledVisualTopSelected" Storyboard.TargetProperty="(UIElement.Opacity)"> <SplineDoubleKeyFrame KeyTime="0" Value="1"/> </DoubleAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames Storyboard.TargetName="DisabledVisualTopUnSelected" Storyboard.TargetProperty="(UIElement.Opacity)"> <SplineDoubleKeyFrame KeyTime="0" Value="1"/> </DoubleAnimationUsingKeyFrames> </Storyboard> </VisualState> </VisualStateGroup> <VisualStateGroup x:Name="SelectionStates"> <VisualState x:Name="Unselected"/> <VisualState x:Name="Selected"/> </VisualStateGroup> <VisualStateGroup x:Name="FocusStates"> <VisualState x:Name="Focused"> <Storyboard> <ObjectAnimationUsingKeyFrames Duration="0" Storyboard.TargetName="FocusVisualTop" Storyboard.TargetProperty="Visibility"> <DiscreteObjectKeyFrame KeyTime="0" Value="Visible"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="Unfocused"> <Storyboard> <ObjectAnimationUsingKeyFrames Duration="0" Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Visibility"> <DiscreteObjectKeyFrame KeyTime="0" Value="Collapsed"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> </VisualStateGroup> </VisualStateManager.VisualStateGroups> <Grid x:Name="TemplateTopUnselected" Margin="1"> <Border x:Name="BorderTop" BorderThickness="1,1,1,0"> <Border x:Name="GradientTop" BorderThickness="1,1,1,0" CornerRadius="5,5,0,0"> <Border.BorderBrush> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"> <GradientStop Color="#FFB1CCEE" Offset="0"/> <GradientStop Color="#CCB1CCEE" Offset="1"/> </LinearGradientBrush> </Border.BorderBrush> <Border.Background> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"> <GradientStop Color="#FFCEE0F7" Offset="0.091"/> <GradientStop Color="#FFDEECFD" Offset="0.996"/> <GradientStop Color="White"/> </LinearGradientBrush> </Border.Background> <Grid Margin="3,3,3,2"> <Grid.RowDefinitions> <RowDefinition Height="16"/> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="16"/> <ColumnDefinition/> <ColumnDefinition Width="15"/> </Grid.ColumnDefinitions> <Image x:Name="TabInactiveIcon" Source="group.png" Margin="0" HorizontalAlignment="Center" VerticalAlignment="Center" Opacity="0.395"/> <ContentControl x:Name="HeaderTopUnselected" Cursor="{TemplateBinding Cursor}" Margin="3,0" FontSize="{TemplateBinding FontSize}" Foreground="#FF416AA3" IsTabStop="False" FontFamily="Tahoma" Grid.Column="1" HorizontalAlignment="Center" VerticalAlignment="Center"/> <Button x:Name="TabInactiveCloseButton" Template="{StaticResource TabItemCloseButton}" Cursor="Hand" Height="10" HorizontalAlignment="Right" Margin="0" VerticalAlignment="Top" Width="10" Content="Button" Grid.Column="2" d:LayoutOverrides="GridBox"/> </Grid> </Border> </Border> <Border x:Name="DisabledVisualTopUnSelected" IsHitTestVisible="false" Opacity="0" Background="#8CFFFFFF" CornerRadius="3,3,0,0"/> </Grid> <Border x:Name="FocusVisualElement" Margin="-1" IsHitTestVisible="false" Visibility="Collapsed" BorderBrush="#FF6DBDD1" BorderThickness="1" CornerRadius="3,3,0,0"/> <Grid x:Name="TemplateTopSelected" Margin="0,0,0,-3" Visibility="Collapsed"> <Border x:Name="BorderTop1" BorderThickness="1,1,1,0"> <Border x:Name="GradientTop1" BorderThickness="1,1,1,0" CornerRadius="5,5,0,0"> <Border.BorderBrush> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"> <GradientStop Color="#FFB1CCEE" Offset="0"/> <GradientStop Color="#CAB1CCEE" Offset="1"/> </LinearGradientBrush> </Border.BorderBrush> <Border.Background> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"> <GradientStop Color="#FFCEE0F7" Offset="0.091"/> <GradientStop Color="White" Offset="0.974"/> <GradientStop Color="White"/> </LinearGradientBrush> </Border.Background> <Grid Margin="3,3,3,2"> <Grid.RowDefinitions> <RowDefinition Height="16"/> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="16"/> <ColumnDefinition/> <ColumnDefinition Width="15"/> </Grid.ColumnDefinitions> <Image x:Name="TabActiveIcon" Source="user.png" Margin="0" HorizontalAlignment="Center" VerticalAlignment="Center"/> <ContentControl x:Name="HeaderTopSelected" Cursor="{TemplateBinding Cursor}" Margin="3,0" FontSize="{TemplateBinding FontSize}" Foreground="#FF416AA3" IsTabStop="False" FontFamily="Tahoma" FontWeight="Bold" Grid.Column="1" HorizontalAlignment="Center" VerticalAlignment="Center"/> <Button x:Name="TabActiveCloseButton" Template="{StaticResource TabActiveCloseButton}" Cursor="Hand" Height="10" HorizontalAlignment="Right" Margin="0" VerticalAlignment="Top" Width="10" Content="Button" Grid.Column="2" d:LayoutOverrides="GridBox"/> </Grid> </Border> </Border> <Border x:Name="FocusVisualTop" Margin="-2,-2,-2,0" IsHitTestVisible="false" Visibility="Collapsed" BorderThickness="1,1,1,0" CornerRadius="3,3,0,0"/> <Border x:Name="DisabledVisualTopSelected" Margin="-2,-2,-2,0" IsHitTestVisible="false" Opacity="0" Background="#8CFFFFFF" CornerRadius="3,3,0,0"/> </Grid> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> and my class public class ClosableTabItem : TabItem { public static readonly DependencyProperty TabIconProperty = DependencyProperty.RegisterAttached("TabInactiveIcon", typeof(Image), typeof(ClosableTabItem), null); public Image TabIcon { get { return (Image)GetValue(ClosableTabItem.TabIconProperty); } set { SetValue(ClosableTabItem.TabIconProperty, value); } } public ClosableTabItem(string header, ContentControl content, TabItemIcons icon) { // I need to be able to set the header, content and icon here } private Image GetTabIcon(TabItemIcons icon) { Image img = new Image(); switch (icon) { case TabItemIcons.User: img.Source = new BitmapImage(new Uri("/icons/user.png", UriKind.Relative)); break; case TabItemIcons.Group: img.Source = new BitmapImage(new Uri("/icons/group.png", UriKind.Relative)); break; default: break; } return img; } } This is driving me nuts, and I can't find any examples where anyone has done this without having a xaml page for the custom tab. Is this even possible? Can someone point me in the right direction? Cheers! - jonah

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  • ASP.NET MVC - dropdown list post handling problem

    - by ile
    I've had troubles for a few days already with handling form that contains dropdown list. I tried all that I've learned so far but nothing helps. This is my code: using System; using System.Collections.Generic; using System.Linq; using System.Web; using CMS; using CMS.Model; using System.ComponentModel.DataAnnotations; namespace Portal.Models { public class ArticleDisplay { public ArticleDisplay() { } public int CategoryID { set; get; } public string CategoryTitle { set; get; } public int ArticleID { set; get; } public string ArticleTitle { set; get; } public DateTime ArticleDate; public string ArticleContent { set; get; } } public class HomePageViewModel { public HomePageViewModel(IEnumerable<ArticleDisplay> summaries, Article article) { this.ArticleSummaries = summaries; this.NewArticle = article; } public IEnumerable<ArticleDisplay> ArticleSummaries { get; private set; } public Article NewArticle { get; private set; } } public class ArticleRepository { private DB db = new DB(); // // Query Methods public IQueryable<ArticleDisplay> FindAllArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID orderby article.Date descending select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public IQueryable<ArticleDisplay> FindTodayArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where article.Date == DateTime.Today select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public Article GetArticle(int id) { return db.Articles.SingleOrDefault(d => d.ArticleID == id); } public IQueryable<ArticleDisplay> DetailsArticle(int id) { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where id == article.ArticleID select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } // // Insert/Delete Methods public void Add(Article article) { db.Articles.InsertOnSubmit(article); } public void Delete(Article article) { db.Articles.DeleteOnSubmit(article); } // // Persistence public void Save() { db.SubmitChanges(); } } } using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using Portal.Models; using CMS.Model; namespace Portal.Areas.CMS.Controllers { public class ArticleController : Controller { ArticleRepository articleRepository = new ArticleRepository(); ArticleCategoryRepository articleCategoryRepository = new ArticleCategoryRepository(); // // GET: /Article/ public ActionResult Index() { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); Article article = new Article() { Date = DateTime.Now, CategoryID = 1 }; HomePageViewModel homeData = new HomePageViewModel(articleRepository.FindAllArticles().ToList(), article); return View(homeData); } // // GET: /Article/Details/5 public ActionResult Details(int id) { var article = articleRepository.DetailsArticle(id).Single(); if (article == null) return View("NotFound"); return View(article); } // // GET: /Article/Create //public ActionResult Create() //{ // ViewData["categories"] = new SelectList // ( // articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" // ); // Article article = new Article() // { // Date = DateTime.Now, // CategoryID = 1 // }; // return View(article); //} // // POST: /Article/Create [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Article article) { if (ModelState.IsValid) { try { // TODO: Add insert logic here articleRepository.Add(article); articleRepository.Save(); return RedirectToAction("Index"); } catch { return View(article); } } else { return View(article); } } // // GET: /Article/Edit/5 public ActionResult Edit(int id) { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); var article = articleRepository.GetArticle(id); return View(article); } // // POST: /Article/Edit/5 [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(int id, FormCollection collection) { Article article = articleRepository.GetArticle(id); try { // TODO: Add update logic here UpdateModel(article, collection.ToValueProvider()); articleRepository.Save(); return RedirectToAction("Details", new { id = article.ArticleID }); } catch { return View(article); } } // // HTTP GET: /Article/Delete/1 public ActionResult Delete(int id) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); else return View(article); } // // HTTP POST: /Article/Delete/1 [AcceptVerbs(HttpVerbs.Post)] public ActionResult Delete(int id, string confirmButton) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); articleRepository.Delete(article); articleRepository.Save(); return View("Deleted"); } [ValidateInput(false)] public ActionResult UpdateSettings(int id, string value, string field) { // This highly-specific example is from the original coder's blog system, // but you can substitute your own code here. I assume you can pick out // which text field it is from the id. Article article = articleRepository.GetArticle(id); if (article == null) return Content("Error"); if (field == "Title") { article.Title = value; UpdateModel(article, new[] { "Title" }); articleRepository.Save(); } if (field == "Content") { article.Content = value; UpdateModel(article, new[] { "Content" }); articleRepository.Save(); } if (field == "Date") { article.Date = Convert.ToDateTime(value); UpdateModel(article, new[] { "Date" }); articleRepository.Save(); } return Content(value); } } } and view: <%@ Page Title="" Language="C#" MasterPageFile="~/Areas/CMS/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Portal.Models.HomePageViewModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Index </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <div class="naslov_poglavlja_main">Articles Administration</div> <%= Html.ValidationSummary("Create was unsuccessful. Please correct the errors and try again.") %> <% using (Html.BeginForm("Create","Article")) {%> <div class="news_forma"> <label for="Title" class="news">Title:</label> <%= Html.TextBox("Title", "", new { @class = "news" })%> <%= Html.ValidationMessage("Title", "*") %> <label for="Content" class="news">Content:</label> <div class="textarea_okvir"> <%= Html.TextArea("Content", "", new { @class = "news" })%> <%= Html.ValidationMessage("Content", "*")%> </div> <label for="CategoryID" class="news">Category:</label> <%= Html.DropDownList("CategoryId", (IEnumerable<SelectListItem>)ViewData["categories"], new { @class = "news" })%> <p> <input type="submit" value="Publish" class="form_submit" /> </p> </div> <% } %> <div class="naslov_poglavlja_main"><%= Html.ActionLink("Write new article...", "Create") %></div> <div id="articles"> <% foreach (var item in Model.ArticleSummaries) { %> <div> <div class="naslov_vijesti" id="<%= item.ArticleID %>"><%= Html.Encode(item.ArticleTitle) %></div> <div class="okvir_vijesti"> <div class="sadrzaj_vijesti" id="<%= item.ArticleID %>"><%= item.ArticleContent %></div> <div class="datum_vijesti" id="<%= item.ArticleID %>"><%= Html.Encode(String.Format("{0:g}", item.ArticleDate)) %></div> <a class="news_delete" href="#" id="<%= item.ArticleID %>">Delete</a> </div> <div class="dno"></div> </div> <% } %> </div> </asp:Content> When trying to post new article I get following error: System.InvalidOperationException: The ViewData item that has the key 'CategoryId' is of type 'System.Int32' but must be of type 'IEnumerable'. I really don't know what to do cause I'm pretty new to .net and mvc Any help appreciated! Ile EDIT: I found where I made mistake. I didn't include date. If in view form I add this line I'm able to add article: <%=Html.Hidden("Date", String.Format("{0:g}", Model.NewArticle.Date)) %> But, if I enter wrong datetype or leave title and content empty then I get the same error. In this eample there is no need for date edit, but I will need it for some other forms and validation will be necessary. EDIT 2: Error happens when posting! Call stack: App_Web_of9beco9.dll!ASP.areas_cms_views_article_create_aspx.__RenderContent2(System.Web.UI.HtmlTextWriter __w = {System.Web.UI.HtmlTextWriter}, System.Web.UI.Control parameterContainer = {System.Web.UI.WebControls.ContentPlaceHolder}) Line 31 + 0x9f bytes C#

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  • Wicket, Spring and Hibernate - Testing with Unitils - Error: Table not found in statement [select re

    - by John
    Hi there. I've been following a tutorial and a sample application, namely 5 Days of Wicket - Writing the tests: http://www.mysticcoders.com/blog/2009/03/10/5-days-of-wicket-writing-the-tests/ I've set up my own little project with a simple shoutbox that saves messages to a database. I then wanted to set up a couple of tests that would make sure that if a message is stored in the database, the retrieved object would contain the exact same data. Upon running mvn test all my tests fail. The exception has been pasted in the first code box underneath. I've noticed that even though my unitils.properties says to use the 'hdqldb'-dialect, this message is still output in the console window when starting the tests: INFO - Dialect - Using dialect: org.hibernate.dialect.PostgreSQLDialect. I've added the entire dump from the console as well at the bottom of this post (which goes on for miles and miles :-)). Upon running mvn test all my tests fail, and the exception is: Caused by: java.sql.SQLException: Table not found in statement [select relname from pg_class] at org.hsqldb.jdbc.Util.sqlException(Unknown Source) at org.hsqldb.jdbc.jdbcStatement.fetchResult(Unknown Source) at org.hsqldb.jdbc.jdbcStatement.executeQuery(Unknown Source) at org.apache.commons.dbcp.DelegatingStatement.executeQuery(DelegatingStatement.java:188) at org.hibernate.tool.hbm2ddl.DatabaseMetadata.initSequences(DatabaseMetadata.java:151) at org.hibernate.tool.hbm2ddl.DatabaseMetadata.(DatabaseMetadata.java:69) at org.hibernate.tool.hbm2ddl.DatabaseMetadata.(DatabaseMetadata.java:62) at org.springframework.orm.hibernate3.LocalSessionFactoryBean$3.doInHibernate(LocalSessionFactoryBean.java:958) at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:419) ... 49 more I've set up my unitils.properties file like so: database.driverClassName=org.hsqldb.jdbcDriver database.url=jdbc:hsqldb:mem:PUBLIC database.userName=sa database.password= database.dialect=hsqldb database.schemaNames=PUBLIC My abstract IntegrationTest class: @SpringApplicationContext({"/com/upbeat/shoutbox/spring/applicationContext.xml", "applicationContext-test.xml"}) public abstract class AbstractIntegrationTest extends UnitilsJUnit4 { private ApplicationContext applicationContext; } applicationContext-test.xml: <?xml version="1.0" encoding="UTF-8"? <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd" <bean id="dataSource" class="org.unitils.database.UnitilsDataSourceFactoryBean"/ </beans and finally, one of the test classes: package com.upbeat.shoutbox.web; import org.apache.wicket.spring.injection.annot.test.AnnotApplicationContextMock; import org.apache.wicket.util.tester.WicketTester; import org.junit.Before; import org.junit.Test; import org.unitils.spring.annotation.SpringBeanByType; import com.upbeat.shoutbox.HomePage; import com.upbeat.shoutbox.integrations.AbstractIntegrationTest; import com.upbeat.shoutbox.persistence.ShoutItemDao; import com.upbeat.shoutbox.services.ShoutService; public class TestHomePage extends AbstractIntegrationTest { @SpringBeanByType private ShoutService svc; @SpringBeanByType private ShoutItemDao dao; protected WicketTester tester; @Before public void setUp() { AnnotApplicationContextMock appctx = new AnnotApplicationContextMock(); appctx.putBean("shoutItemDao", dao); appctx.putBean("shoutService", svc); tester = new WicketTester(); } @Test public void testRenderMyPage() { //start and render the test page tester.startPage(HomePage.class); //assert rendered page class tester.assertRenderedPage(HomePage.class); //assert rendered label component tester.assertLabel("message", "If you see this message wicket is properly configured and running"); } } Dump from console when running mvn test: [INFO] Scanning for projects... [INFO] ------------------------------------------------------------------------ [INFO] Building shoutbox [INFO] task-segment: [test] [INFO] ------------------------------------------------------------------------ [INFO] [resources:resources {execution: default-resources}] [WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent! [WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 3 resources [INFO] Copying 4 resources [INFO] [compiler:compile {execution: default-compile}] [INFO] Nothing to compile - all classes are up to date [INFO] [resources:testResources {execution: default-testResources}] [WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent! [WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 2 resources [INFO] [compiler:testCompile {execution: default-testCompile}] [INFO] Nothing to compile - all classes are up to date [INFO] [surefire:test {execution: default-test}] [INFO] Surefire report directory: F:\Projects\shoutbox\target\surefire-reports INFO - ConfigurationLoader - Loaded main configuration file unitils-default.properties from classpath. INFO - ConfigurationLoader - Loaded custom configuration file unitils.properties from classpath. INFO - ConfigurationLoader - No local configuration file unitils-local.properties found. ------------------------------------------------------- T E S T S ------------------------------------------------------- Running com.upbeat.shoutbox.web.TestViewShoutsPage Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.02 sec INFO - Version - Hibernate Annotations 3.4.0.GA INFO - Environment - Hibernate 3.3.0.SP1 INFO - Environment - hibernate.properties not found INFO - Environment - Bytecode provider name : javassist INFO - Environment - using JDK 1.4 java.sql.Timestamp handling INFO - Version - Hibernate Commons Annotations 3.1.0.GA INFO - AnnotationBinder - Binding entity from annotated class: com.upbeat.shoutbox.models.ShoutItem INFO - QueryBinder - Binding Named query: item.getById = from ShoutItem item where item.id = :id INFO - QueryBinder - Binding Named query: item.find = from ShoutItem item order by item.timestamp desc INFO - QueryBinder - Binding Named query: item.count = select count(item) from ShoutItem item INFO - EntityBinder - Bind entity com.upbeat.shoutbox.models.ShoutItem on table SHOUT_ITEMS INFO - AnnotationConfiguration - Hibernate Validator not found: ignoring INFO - notationSessionFactoryBean - Building new Hibernate SessionFactory INFO - earchEventListenerRegister - Unable to find org.hibernate.search.event.FullTextIndexEventListener on the classpath. Hibernate Search is not enabled. INFO - ConnectionProviderFactory - Initializing connection provider: org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider INFO - SettingsFactory - RDBMS: HSQL Database Engine, version: 1.8.0 INFO - SettingsFactory - JDBC driver: HSQL Database Engine Driver, version: 1.8.0 INFO - Dialect - Using dialect: org.hibernate.dialect.PostgreSQLDialect INFO - TransactionFactoryFactory - Transaction strategy: org.springframework.orm.hibernate3.SpringTransactionFactory INFO - actionManagerLookupFactory - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) INFO - SettingsFactory - Automatic flush during beforeCompletion(): disabled INFO - SettingsFactory - Automatic session close at end of transaction: disabled INFO - SettingsFactory - JDBC batch size: 1000 INFO - SettingsFactory - JDBC batch updates for versioned data: disabled INFO - SettingsFactory - Scrollable result sets: enabled INFO - SettingsFactory - JDBC3 getGeneratedKeys(): disabled INFO - SettingsFactory - Connection release mode: auto INFO - SettingsFactory - Default batch fetch size: 1 INFO - SettingsFactory - Generate SQL with comments: disabled INFO - SettingsFactory - Order SQL updates by primary key: disabled INFO - SettingsFactory - Order SQL inserts for batching: disabled INFO - SettingsFactory - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory INFO - ASTQueryTranslatorFactory - Using ASTQueryTranslatorFactory INFO - SettingsFactory - Query language substitutions: {} INFO - SettingsFactory - JPA-QL strict compliance: disabled INFO - SettingsFactory - Second-level cache: enabled INFO - SettingsFactory - Query cache: enabled INFO - SettingsFactory - Cache region factory : org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge INFO - FactoryCacheProviderBridge - Cache provider: org.hibernate.cache.HashtableCacheProvider INFO - SettingsFactory - Optimize cache for minimal puts: disabled INFO - SettingsFactory - Structured second-level cache entries: disabled INFO - SettingsFactory - Query cache factory: org.hibernate.cache.StandardQueryCacheFactory INFO - SettingsFactory - Echoing all SQL to stdout INFO - SettingsFactory - Statistics: disabled INFO - SettingsFactory - Deleted entity synthetic identifier rollback: disabled INFO - SettingsFactory - Default entity-mode: pojo INFO - SettingsFactory - Named query checking : enabled INFO - SessionFactoryImpl - building session factory INFO - essionFactoryObjectFactory - Not binding factory to JNDI, no JNDI name configured INFO - UpdateTimestampsCache - starting update timestamps cache at region: org.hibernate.cache.UpdateTimestampsCache INFO - StandardQueryCache - starting query cache at region: org.hibernate.cache.StandardQueryCache INFO - notationSessionFactoryBean - Updating database schema for Hibernate SessionFactory INFO - Dialect - Using dialect: org.hibernate.dialect.PostgreSQLDialect INFO - XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [org/springframework/jdbc/support/sql-error-codes.xml] INFO - SQLErrorCodesFactory - SQLErrorCodes loaded: [DB2, Derby, H2, HSQL, Informix, MS-SQL, MySQL, Oracle, PostgreSQL, Sybase] INFO - DefaultListableBeanFactory - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@3e0ebb: defining beans [propertyConfigurer,dataSource,sessionFactory,shoutService,shoutItemDao,wicketApplication,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,transactionManager]; root of factory hierarchy INFO - sPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@a8e586: display name [org.springframework.context.support.ClassPathXmlApplicationContext@a8e586]; startup date [Tue May 04 18:19:58 CEST 2010]; root of context hierarchy INFO - XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [com/upbeat/shoutbox/spring/applicationContext.xml] INFO - XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [applicationContext-test.xml] INFO - DefaultListableBeanFactory - Overriding bean definition for bean 'dataSource': replacing [Generic bean: class [org.apache.commons.dbcp.BasicDataSource]; scope=singleton; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=close; defined in class path resource [com/upbeat/shoutbox/spring/applicationContext.xml]] with [Generic bean: class [org.unitils.database.UnitilsDataSourceFactoryBean]; scope=singleton; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null; defined in class path resource [applicationContext-test.xml]] INFO - sPathXmlApplicationContext - Bean factory for application context [org.springframework.context.support.ClassPathXmlApplicationContext@a8e586]: org.springframework.beans.factory.support.DefaultListableBeanFactory@5dfaf1 INFO - pertyPlaceholderConfigurer - Loading properties file from class path resource [application.properties] INFO - DefaultListableBeanFactory - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@5dfaf1: defining beans [propertyConfigurer,dataSource,sessionFactory,shoutService,shoutItemDao,wicketApplication,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,transactionManager]; root of factory hierarchy INFO - AnnotationBinder - Binding entity from annotated class: com.upbeat.shoutbox.models.ShoutItem INFO - QueryBinder - Binding Named query: item.getById = from ShoutItem item where item.id = :id INFO - QueryBinder - Binding Named query: item.find = from ShoutItem item order by item.timestamp desc INFO - QueryBinder - Binding Named query: item.count = select count(item) from ShoutItem item INFO - EntityBinder - Bind entity com.upbeat.shoutbox.models.ShoutItem on table SHOUT_ITEMS INFO - AnnotationConfiguration - Hibernate Validator not found: ignoring INFO - notationSessionFactoryBean - Building new Hibernate SessionFactory INFO - earchEventListenerRegister - Unable to find org.hibernate.search.event.FullTextIndexEventListener on the classpath. Hibernate Search is not enabled. INFO - ConnectionProviderFactory - Initializing connection provider: org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider INFO - SettingsFactory - RDBMS: HSQL Database Engine, version: 1.8.0 INFO - SettingsFactory - JDBC driver: HSQL Database Engine Driver, version: 1.8.0 INFO - Dialect - Using dialect: org.hibernate.dialect.PostgreSQLDialect INFO - TransactionFactoryFactory - Transaction strategy: org.springframework.orm.hibernate3.SpringTransactionFactory INFO - actionManagerLookupFactory - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) INFO - SettingsFactory - Automatic flush during beforeCompletion(): disabled INFO - SettingsFactory - Automatic session close at end of transaction: disabled INFO - SettingsFactory - JDBC batch size: 1000 INFO - SettingsFactory - JDBC batch updates for versioned data: disabled INFO - SettingsFactory - Scrollable result sets: enabled INFO - SettingsFactory - JDBC3 getGeneratedKeys(): disabled INFO - SettingsFactory - Connection release mode: auto INFO - SettingsFactory - Default batch fetch size: 1 INFO - SettingsFactory - Generate SQL with comments: disabled INFO - SettingsFactory - Order SQL updates by primary key: disabled INFO - SettingsFactory - Order SQL inserts for batching: disabled INFO - SettingsFactory - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory INFO - ASTQueryTranslatorFactory - Using ASTQueryTranslatorFactory INFO - SettingsFactory - Query language substitutions: {} INFO - SettingsFactory - JPA-QL strict compliance: disabled INFO - SettingsFactory - Second-level cache: enabled INFO - SettingsFactory - Query cache: enabled INFO - SettingsFactory - Cache region factory : org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge INFO - FactoryCacheProviderBridge - Cache provider: org.hibernate.cache.HashtableCacheProvider INFO - SettingsFactory - Optimize cache for minimal puts: disabled INFO - SettingsFactory - Structured second-level cache entries: disabled INFO - SettingsFactory - Query cache factory: org.hibernate.cache.StandardQueryCacheFactory INFO - SettingsFactory - Echoing all SQL to stdout INFO - SettingsFactory - Statistics: disabled INFO - SettingsFactory - Deleted entity synthetic identifier rollback: disabled INFO - SettingsFactory - Default entity-mode: pojo INFO - SettingsFactory - Named query checking : enabled INFO - SessionFactoryImpl - building session factory INFO - essionFactoryObjectFactory - Not binding factory to JNDI, no JNDI name configured INFO - UpdateTimestampsCache - starting update timestamps cache at region: org.hibernate.cache.UpdateTimestampsCache INFO - StandardQueryCache - starting query cache at region: org.hibernate.cache.StandardQueryCache INFO - notationSessionFactoryBean - Updating database schema for Hibernate SessionFactory INFO - Dialect - Using dialect: org.hibernate.dialect.PostgreSQLDialect INFO - DefaultListableBeanFactory - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@5dfaf1: defining beans [propertyConfigurer,dataSource,sessionFactory,shoutService,shoutItemDao,wicketApplication,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,transactionManager]; root of factory hierarchy Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 1.34 sec <<< FAILURE! Running com.upbeat.shoutbox.integrations.ShoutItemIntegrationTest Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0 sec <<< FAILURE! Running com.upbeat.shoutbox.mocks.ShoutServiceTest Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.01 sec <<< FAILURE! Results : Tests in error: initializationError(com.upbeat.shoutbox.web.TestViewShoutsPage) testRenderMyPage(com.upbeat.shoutbox.web.TestHomePage) initializationError(com.upbeat.shoutbox.integrations.ShoutItemIntegrationTest) initializationError(com.upbeat.shoutbox.mocks.ShoutServiceTest) Tests run: 4, Failures: 0, Errors: 4, Skipped: 0 [INFO] ------------------------------------------------------------------------ [ERROR] BUILD FAILURE [INFO] ------------------------------------------------------------------------ [INFO] There are test failures. Please refer to F:\Projects\shoutbox\target\surefire-reports for the individual test results. [INFO] ------------------------------------------------------------------------ [INFO] For more information, run Maven with the -e switch [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3 seconds [INFO] Finished at: Tue May 04 18:19:58 CEST 2010 [INFO] Final Memory: 13M/31M [INFO] ------------------------------------------------------------------------ Any help is greatly appreciated.

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  • Combining MVVM Light Toolkit and Unity 2.0

    - by Alan Cordner
    This is more of a commentary than a question, though feedback would be nice. I have been tasked to create the user interface for a new project we are doing. We want to use WPF and I wanted to learn all of the modern UI design techniques available. Since I am fairly new to WPF I have been researching what is available. I think I have pretty much settled on using MVVM Light Toolkit (mainly because of its "Blendability" and the EventToCommand behavior!), but I wanted to incorporate IoC also. So, here is what I have come up with. I have modified the default ViewModelLocator class in a MVVM Light project to use a UnityContainer to handle dependency injections. Considering I didn't know what 90% of these terms meant 3 months ago, I think I'm on the right track. // Example of MVVM Light Toolkit ViewModelLocator class that implements Microsoft // Unity 2.0 Inversion of Control container to resolve ViewModel dependencies. using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { public class ViewModelLocator { public static UnityContainer Container { get; set; } #region Constructors static ViewModelLocator() { if (Container == null) { Container = new UnityContainer(); // register all dependencies required by view models Container .RegisterType<IDialogService, ModalDialogService>(new ContainerControlledLifetimeManager()) .RegisterType<ILoggerService, LogFileService>(new ContainerControlledLifetimeManager()) ; } } /// <summary> /// Initializes a new instance of the ViewModelLocator class. /// </summary> public ViewModelLocator() { ////if (ViewModelBase.IsInDesignModeStatic) ////{ //// // Create design time view models ////} ////else ////{ //// // Create run time view models ////} CreateMain(); } #endregion #region MainViewModel private static MainViewModel _main; /// <summary> /// Gets the Main property. /// </summary> public static MainViewModel MainStatic { get { if (_main == null) { CreateMain(); } return _main; } } /// <summary> /// Gets the Main property. /// </summary> [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "This non-static member is needed for data binding purposes.")] public MainViewModel Main { get { return MainStatic; } } /// <summary> /// Provides a deterministic way to delete the Main property. /// </summary> public static void ClearMain() { _main.Cleanup(); _main = null; } /// <summary> /// Provides a deterministic way to create the Main property. /// </summary> public static void CreateMain() { if (_main == null) { // allow Unity to resolve the view model and hold onto reference _main = Container.Resolve<MainViewModel>(); } } #endregion #region OrderViewModel // property to hold the order number (injected into OrderViewModel() constructor when resolved) public static string OrderToView { get; set; } /// <summary> /// Gets the OrderViewModel property. /// </summary> public static OrderViewModel OrderViewModelStatic { get { // allow Unity to resolve the view model // do not keep local reference to the instance resolved because we need a new instance // each time - the corresponding View is a UserControl that can be used multiple times // within a single window/view // pass current value of OrderToView parameter to constructor! return Container.Resolve<OrderViewModel>(new ParameterOverride("orderNumber", OrderToView)); } } /// <summary> /// Gets the OrderViewModel property. /// </summary> [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "This non-static member is needed for data binding purposes.")] public OrderViewModel Order { get { return OrderViewModelStatic; } } #endregion /// <summary> /// Cleans up all the resources. /// </summary> public static void Cleanup() { ClearMain(); Container = null; } } } And the MainViewModel class showing dependency injection usage: using GalaSoft.MvvmLight; using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { public class MainViewModel : ViewModelBase { private IDialogService _dialogs; private ILoggerService _logger; /// <summary> /// Initializes a new instance of the MainViewModel class. This default constructor calls the /// non-default constructor resolving the interfaces used by this view model. /// </summary> public MainViewModel() : this(ViewModelLocator.Container.Resolve<IDialogService>(), ViewModelLocator.Container.Resolve<ILoggerService>()) { if (IsInDesignMode) { // Code runs in Blend --> create design time data. } else { // Code runs "for real" } } /// <summary> /// Initializes a new instance of the MainViewModel class. /// Interfaces are automatically resolved by the IoC container. /// </summary> /// <param name="dialogs">Interface to dialog service</param> /// <param name="logger">Interface to logger service</param> public MainViewModel(IDialogService dialogs, ILoggerService logger) { _dialogs = dialogs; _logger = logger; if (IsInDesignMode) { // Code runs in Blend --> create design time data. _dialogs.ShowMessage("Running in design-time mode!", "Injection Constructor", DialogButton.OK, DialogImage.Information); _logger.WriteLine("Running in design-time mode!"); } else { // Code runs "for real" _dialogs.ShowMessage("Running in run-time mode!", "Injection Constructor", DialogButton.OK, DialogImage.Information); _logger.WriteLine("Running in run-time mode!"); } } public override void Cleanup() { // Clean up if needed _dialogs = null; _logger = null; base.Cleanup(); } } } And the OrderViewModel class: using GalaSoft.MvvmLight; using Microsoft.Practices.Unity; namespace MVVMLightUnityExample { /// <summary> /// This class contains properties that a View can data bind to. /// <para> /// Use the <strong>mvvminpc</strong> snippet to add bindable properties to this ViewModel. /// </para> /// <para> /// You can also use Blend to data bind with the tool's support. /// </para> /// <para> /// See http://www.galasoft.ch/mvvm/getstarted /// </para> /// </summary> public class OrderViewModel : ViewModelBase { private const string testOrderNumber = "123456"; private Order _order; /// <summary> /// Initializes a new instance of the OrderViewModel class. /// </summary> public OrderViewModel() : this(testOrderNumber) { } /// <summary> /// Initializes a new instance of the OrderViewModel class. /// </summary> public OrderViewModel(string orderNumber) { if (IsInDesignMode) { // Code runs in Blend --> create design time data. _order = new Order(orderNumber, "My Company", "Our Address"); } else { _order = GetOrder(orderNumber); } } public override void Cleanup() { // Clean own resources if needed _order = null; base.Cleanup(); } } } And the code that could be used to display an order view for a specific order: public void ShowOrder(string orderNumber) { // pass the order number to show to ViewModelLocator to be injected //into the constructor of the OrderViewModel instance ViewModelLocator.OrderToShow = orderNumber; View.OrderView orderView = new View.OrderView(); } These examples have been stripped down to show only the IoC ideas. It took a lot of trial and error, searching the internet for examples, and finding out that the Unity 2.0 documentation is lacking (at best) to come up with this solution. Let me know if you think it could be improved.

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