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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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  • Microsoft Introduces WebMatrix

    - by Rick Strahl
    originally published in CoDe Magazine Editorial Microsoft recently released the first CTP of a new development environment called WebMatrix, which along with some of its supporting technologies are squarely aimed at making the Microsoft Web Platform more approachable for first-time developers and hobbyists. But in the process, it also provides some updated technologies that can make life easier for existing .NET developers. Let’s face it: ASP.NET development isn’t exactly trivial unless you already have a fair bit of familiarity with sophisticated development practices. Stick a non-developer in front of Visual Studio .NET or even the Visual Web Developer Express edition and it’s not likely that the person in front of the screen will be very productive or feel inspired. Yet other technologies like PHP and even classic ASP did provide the ability for non-developers and hobbyists to become reasonably proficient in creating basic web content quickly and efficiently. WebMatrix appears to be Microsoft’s attempt to bring back some of that simplicity with a number of technologies and tools. The key is to provide a friendly and fully self-contained development environment that provides all the tools needed to build an application in one place, as well as tools that allow publishing of content and databases easily to the web server. WebMatrix is made up of several components and technologies: IIS Developer Express IIS Developer Express is a new, self-contained development web server that is fully compatible with IIS 7.5 and based on the same codebase that IIS 7.5 uses. This new development server replaces the much less compatible Cassini web server that’s been used in Visual Studio and the Express editions. IIS Express addresses a few shortcomings of the Cassini server such as the inability to serve custom ISAPI extensions (i.e., things like PHP or ASP classic for example), as well as not supporting advanced authentication. IIS Developer Express provides most of the IIS 7.5 feature set providing much better compatibility between development and live deployment scenarios. SQL Server Compact 4.0 Database access is a key component for most web-driven applications, but on the Microsoft stack this has mostly meant you have to use SQL Server or SQL Server Express. SQL Server Compact is not new-it’s been around for a few years, but it’s been severely hobbled in the past by terrible tool support and the inability to support more than a single connection in Microsoft’s attempt to avoid losing SQL Server licensing. The new release of SQL Server Compact 4.0 supports multiple connections and you can run it in ASP.NET web applications simply by installing an assembly into the bin folder of the web application. In effect, you don’t have to install a special system configuration to run SQL Compact as it is a drop-in database engine: Copy the small assembly into your BIN folder (or from the GAC if installed fully), create a connection string against a local file-based database file, and then start firing SQL requests. Additionally WebMatrix includes nice tools to edit the database tables and files, along with tools to easily upsize (and hopefully downsize in the future) to full SQL Server. This is a big win, pending compatibility and performance limits. In my simple testing the data engine performed well enough for small data sets. This is not only useful for web applications, but also for desktop applications for which a fully installed SQL engine like SQL Server would be overkill. Having a local data store in those applications that can potentially be accessed by multiple users is a welcome feature. ASP.NET Razor View Engine What? Yet another native ASP.NET view engine? We already have Web Forms and various different flavors of using that view engine with Web Forms and MVC. Do we really need another? Microsoft thinks so, and Razor is an implementation of a lightweight, script-only view engine. Unlike the Web Forms view engine, Razor works only with inline code, snippets, and markup; therefore, it is more in line with current thinking of what a view engine should represent. There’s no support for a “page model” or any of the other Web Forms features of the full-page framework, but just a lightweight scripting engine that works with plain markup plus embedded expressions and code. The markup syntax for Razor is geared for minimal typing, plus some progressive detection of where a script block/expression starts and ends. This results in a much leaner syntax than the typical ASP.NET Web Forms alligator (<% %>) tags. Razor uses the @ sign plus standard C# (or Visual Basic) block syntax to delineate code snippets and expressions. Here’s a very simple example of what Razor markup looks like along with some comment annotations: <!DOCTYPE html> <html>     <head>         <title></title>     </head>     <body>     <h1>Razor Test</h1>          <!-- simple expressions -->     @DateTime.Now     <hr />     <!-- method expressions -->     @DateTime.Now.ToString("T")          <!-- code blocks -->     @{         List<string> names = new List<string>();         names.Add("Rick");         names.Add("Markus");         names.Add("Claudio");         names.Add("Kevin");     }          <!-- structured block statements -->     <ul>     @foreach(string name in names){             <li>@name</li>     }     </ul>           <!-- Conditional code -->        @if(true) {                        <!-- Literal Text embedding in code -->        <text>         true        </text>;    }    else    {        <!-- Literal Text embedding in code -->       <text>       false       </text>;    }    </body> </html> Like the Web Forms view engine, Razor parses pages into code, and then executes that run-time compiled code. Effectively a “page” becomes a code file with markup becoming literal text written into the Response stream, code snippets becoming raw code, and expressions being written out with Response.Write(). The code generated from Razor doesn’t look much different from similar Web Forms code that only uses script tags; so although the syntax may look different, the operational model is fairly similar to the Web Forms engine minus the overhead of the large Page object model. However, there are differences: -Razor pages are based on a new base class, Microsoft.WebPages.WebPage, which is hosted in the Microsoft.WebPages assembly that houses all the Razor engine parsing and processing logic. Browsing through the assembly (in the generated ASP.NET Temporary Files folder or GAC) will give you a good idea of the functionality that Razor provides. If you look closely, a lot of the feature set matches ASP.NET MVC’s view implementation as well as many of the helper classes found in MVC. It’s not hard to guess the motivation for this sort of view engine: For beginning developers the simple markup syntax is easier to work with, although you obviously still need to have some understanding of the .NET Framework in order to create dynamic content. The syntax is easier to read and grok and much shorter to type than ASP.NET alligator tags (<% %>) and also easier to understand aesthetically what’s happening in the markup code. Razor also is a better fit for Microsoft’s vision of ASP.NET MVC: It’s a new view engine without the baggage of Web Forms attached to it. The engine is more lightweight since it doesn’t carry all the features and object model of Web Forms with it and it can be instantiated directly outside of the HTTP environment, which has been rather tricky to do for the Web Forms view engine. Having a standalone script parser is a huge win for other applications as well – it makes it much easier to create script or meta driven output generators for many types of applications from code/screen generators, to simple form letters to data merging applications with user customizability. For me personally this is very useful side effect and who knows maybe Microsoft will actually standardize they’re scripting engines (die T4 die!) on this engine. Razor also better fits the “view-based” approach where the view is supposed to be mostly a visual representation that doesn’t hold much, if any, code. While you can still use code, the code you do write has to be self-contained. Overall I wouldn’t be surprised if Razor will become the new standard view engine for MVC in the future – and in fact there have been announcements recently that Razor will become the default script engine in ASP.NET MVC 3.0. Razor can also be used in existing Web Forms and MVC applications, although that’s not working currently unless you manually configure the script mappings and add the appropriate assemblies. It’s possible to do it, but it’s probably better to wait until Microsoft releases official support for Razor scripts in Visual Studio. Once that happens, you can simply drop .cshtml and .vbhtml pages into an existing ASP.NET project and they will work side by side with classic ASP.NET pages. WebMatrix Development Environment To tie all of these three technologies together, Microsoft is shipping WebMatrix with an integrated development environment. An integrated gallery manager makes it easy to download and load existing projects, and then extend them with custom functionality. It seems to be a prominent goal to provide community-oriented content that can act as a starting point, be it via a custom templates or a complete standard application. The IDE includes a project manager that works with a single project and provides an integrated IDE/editor for editing the .cshtml and .vbhtml pages. A run button allows you to quickly run pages in the project manager in a variety of browsers. There’s no debugging support for code at this time. Note that Razor pages don’t require explicit compilation, so making a change, saving, and then refreshing your page in the browser is all that’s needed to see changes while testing an application locally. It’s essentially using the auto-compiling Web Project that was introduced with .NET 2.0. All code is compiled during run time into dynamically created assemblies in the ASP.NET temp folder. WebMatrix also has PHP Editing support with syntax highlighting. You can load various PHP-based applications from the WebMatrix Web Gallery directly into the IDE. Most of the Web Gallery applications are ready to install and run without further configuration, with Wizards taking you through installation of tools, dependencies, and configuration of the database as needed. WebMatrix leverages the Web Platform installer to pull the pieces down from websites in a tight integration of tools that worked nicely for the four or five applications I tried this out on. Click a couple of check boxes and fill in a few simple configuration options and you end up with a running application that’s ready to be customized. Nice! You can easily deploy completed applications via WebDeploy (to an IIS server) or FTP directly from within the development environment. The deploy tool also can handle automatically uploading and installing the database and all related assemblies required, making deployment a simple one-click install step. Simplified Database Access The IDE contains a database editor that can edit SQL Compact and SQL Server databases. There is also a Database helper class that facilitates database access by providing easy-to-use, high-level query execution and iteration methods: @{       var db = Database.OpenFile("FirstApp.sdf");     string sql = "select * from customers where Id > @0"; } <ul> @foreach(var row in db.Query(sql,1)){         <li>@row.FirstName @row.LastName</li> } </ul> The query function takes a SQL statement plus any number of positional (@0,@1 etc.) SQL parameters by simple values. The result is returned as a collection of rows which in turn have a row object with dynamic properties for each of the columns giving easy (though untyped) access to each of the fields. Likewise Execute and ExecuteNonQuery allow execution of more complex queries using similar parameter passing schemes. Note these queries use string-based queries rather than LINQ or Entity Framework’s strongly typed LINQ queries. While this may seem like a step back, it’s also in line with the expectations of non .NET script developers who are quite used to writing and using SQL strings in code rather than using OR/M frameworks. The only question is why was something not included from the beginning in .NET and Microsoft made developers build custom implementations of these basic building blocks. The implementation looks a lot like a DataTable-style data access mechanism, but to be fair, this is a common approach in scripting languages. This type of syntax that uses simple, static, data object methods to perform simple data tasks with one line of code are common in scripting languages and are a good match for folks working in PHP/Python, etc. Seems like Microsoft has taken great advantage of .NET 4.0’s dynamic typing to provide this sort of interface for row iteration where each row has properties for each field. FWIW, all the examples demonstrate using local SQL Compact files - I was unable to get a SQL Server connection string to work with the Database class (the connection string wasn’t accepted). However, since the code in the page is still plain old .NET, you can easily use standard ADO.NET code or even LINQ or Entity Framework models that are created outside of WebMatrix in separate assemblies as required. The good the bad the obnoxious - It’s still .NET The beauty (or curse depending on how you look at it :)) of Razor and the compilation model is that, behind it all, it’s still .NET. Although the syntax may look foreign, it’s still all .NET behind the scenes. You can easily access existing tools, helpers, and utilities simply by adding them to the project as references or to the bin folder. Razor automatically recognizes any assembly reference from assemblies in the bin folder. In the default configuration, Microsoft provides a host of helper functions in a Microsoft.WebPages assembly (check it out in the ASP.NET temp folder for your application), which includes a host of HTML Helpers. If you’ve used ASP.NET MVC before, a lot of the helpers should look familiar. Documentation at the moment is sketchy-there’s a very rough API reference you can check out here: http://www.asp.net/webmatrix/tutorials/asp-net-web-pages-api-reference Who needs WebMatrix? Uhm… good Question Clearly Microsoft is trying hard to create an environment with WebMatrix that is easy to use for newbie developers. The goal seems to be simplicity in providing a minimal development environment and an easy-to-use script engine/language that makes it easy to get started with. There’s also some focus on community features that can be used as starting points, such as Web Gallery applications and templates. The community features in particular are very nice and something that would be nice to eventually see in Visual Studio as well. The question is whether this is too little too late. Developers who have been clamoring for a simpler development environment on the .NET stack have mostly left for other simpler platforms like PHP or Python which are catering to the down and dirty developer. Microsoft will be hard pressed to win those folks-and other hardcore PHP developers-back. Regardless of how much you dress up a script engine fronted by the .NET Framework, it’s still the .NET Framework and all the complexity that drives it. While .NET is a fine solution in its breadth and features once you get a basic handle on the core features, the bar of entry to being productive with the .NET Framework is still pretty high. The MVC style helpers Microsoft provides are a good step in the right direction, but I suspect it’s not enough to shield new developers from having to delve much deeper into the Framework to get even basic applications built. Razor and its helpers is trying to make .NET more accessible but the reality is that in order to do useful stuff that goes beyond the handful of simple helpers you still are going to have to write some C# or VB or other .NET code. If the target is a hobby/amateur/non-programmer the learning curve isn’t made any easier by WebMatrix it’s just been shifted a tad bit further along in your development endeavor when you run out of canned components that are supplied either by Microsoft or the community. The database helpers are interesting and actually I’ve heard a lot of discussion from various developers who’ve been resisting .NET for a really long time perking up at the prospect of easier data access in .NET than the ridiculous amount of code it takes to do even simple data access with raw ADO.NET. It seems sad that such a simple concept and implementation should trigger this sort of response (especially since it’s practically trivial to create helpers like these or pick them up from countless libraries available), but there it is. It also shows that there are plenty of developers out there who are more interested in ‘getting stuff done’ easily than necessarily following the latest and greatest practices which are overkill for many development scenarios. Sometimes it seems that all of .NET is focused on the big life changing issues of development, rather than the bread and butter scenarios that many developers are interested in to get their work accomplished. And that in the end may be WebMatrix’s main raison d'être: To bring some focus back at Microsoft that simpler and more high level solutions are actually needed to appeal to the non-high end developers as well as providing the necessary tools for the high end developers who want to follow the latest and greatest trends. The current version of WebMatrix hits many sweet spots, but it also feels like it has a long way to go before it really can be a tool that a beginning developer or an accomplished developer can feel comfortable with. Although there are some really good ideas in the environment (like the gallery for downloading apps and components) which would be a great addition for Visual Studio as well, the rest of the development environment just feels like crippleware with required functionality missing especially debugging and Intellisense, but also general editor support. It’s not clear whether these are because the product is still in an early alpha release or whether it’s simply designed that way to be a really limited development environment. While simple can be good, nobody wants to feel left out when it comes to necessary tool support and WebMatrix just has that left out feeling to it. If anything WebMatrix’s technology pieces (which are really independent of the WebMatrix product) are what are interesting to developers in general. The compact IIS implementation is a nice improvement for development scenarios and SQL Compact 4.0 seems to address a lot of concerns that people have had and have complained about for some time with previous SQL Compact implementations. By far the most interesting and useful technology though seems to be the Razor view engine for its light weight implementation and it’s decoupling from the ASP.NET/HTTP pipeline to provide a standalone scripting/view engine that is pluggable. The first winner of this is going to be ASP.NET MVC which can now have a cleaner view model that isn’t inconsistent due to the baggage of non-implemented WebForms features that don’t work in MVC. But I expect that Razor will end up in many other applications as a scripting and code generation engine eventually. Visual Studio integration for Razor is currently missing, but is promised for a later release. The ASP.NET MVC team has already mentioned that Razor will eventually become the default MVC view engine, which will guarantee continued growth and development of this tool along those lines. And the Razor engine and support tools actually inherit many of the features that MVC pioneered, so there’s some synergy flowing both ways between Razor and MVC. As an existing ASP.NET developer who’s already familiar with Visual Studio and ASP.NET development, the WebMatrix IDE doesn’t give you anything that you want. The tools provided are minimal and provide nothing that you can’t get in Visual Studio today, except the minimal Razor syntax highlighting, so there’s little need to take a step back. With Visual Studio integration coming later there’s little reason to look at WebMatrix for tooling. It’s good to see that Microsoft is giving some thought about the ease of use of .NET as a platform For so many years, we’ve been piling on more and more new features without trying to take a step back and see how complicated the development/configuration/deployment process has become. Sometimes it’s good to take a step - or several steps - back and take another look and realize just how far we’ve come. WebMatrix is one of those reminders and one that likely will result in some positive changes on the platform as a whole. © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET   IIS7  

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  • Capturing and Transforming ASP.NET Output with Response.Filter

    - by Rick Strahl
    During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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  • Web Browser Control &ndash; Specifying the IE Version

    - by Rick Strahl
    I use the Internet Explorer Web Browser Control in a lot of my applications to display document type layout. HTML happens to be one of the most common document formats and displaying data in this format – even in desktop applications, is often way easier than using normal desktop technologies. One issue the Web Browser Control has that it’s perpetually stuck in IE 7 rendering mode by default. Even though IE 8 and now 9 have significantly upgraded the IE rendering engine to be more CSS and HTML compliant by default the Web Browser control will have none of it. IE 9 in particular – with its much improved CSS support and basic HTML 5 support is a big improvement and even though the IE control uses some of IE’s internal rendering technology it’s still stuck in the old IE 7 rendering by default. This applies whether you’re using the Web Browser control in a WPF application, a WinForms app, a FoxPro or VB classic application using the ActiveX control. Behind the scenes all these UI platforms use the COM interfaces and so you’re stuck by those same rules. Rendering Challenged To see what I’m talking about here are two screen shots rendering an HTML 5 doctype page that includes some CSS 3 functionality – rounded corners and border shadows - from an earlier post. One uses IE 9 as a standalone browser, and one uses a simple WPF form that includes the Web Browser control. IE 9 Browser:   Web Browser control in a WPF form: The IE 9 page displays this HTML correctly – you see the rounded corners and shadow displayed. Obviously the latter rendering using the Web Browser control in a WPF application is a bit lacking. Not only are the new CSS features missing but the page also renders in Internet Explorer’s quirks mode so all the margins, padding etc. behave differently by default, even though there’s a CSS reset applied on this page. If you’re building an application that intends to use the Web Browser control for a live preview of some HTML this is clearly undesirable. Feature Delegation via Registry Hacks Fortunately starting with Internet Explore 8 and later there’s a fix for this problem via a registry setting. You can specify a registry key to specify which rendering mode and version of IE should be used by that application. These are not global mind you – they have to be enabled for each application individually. There are two different sets of keys for 32 bit and 64 bit applications. 32 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION Value Key: yourapplication.exe 64 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION Value Key: yourapplication.exe The value to set this key to is (taken from MSDN here) as decimal values: 9999 (0x270F) Internet Explorer 9. Webpages are displayed in IE9 Standards mode, regardless of the !DOCTYPE directive. 9000 (0x2328) Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode. 8888 (0x22B8) Webpages are displayed in IE8 Standards mode, regardless of the !DOCTYPE directive. 8000 (0x1F40) Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode. 7000 (0x1B58) Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode.   The added key looks something like this in the Registry Editor: With this in place my Html Html Help Builder application which has wwhelp.exe as its main executable now works with HTML 5 and CSS 3 documents in the same way that Internet Explorer 9 does. Incidentally I accidentally added an ‘empty’ DWORD value of 0 to my EXE name and that worked as well giving me IE 9 rendering. Although not documented I suspect 0 (or an invalid value) will default to the installed browser. Don’t have a good way to test this but if somebody could try this with IE 8 installed that would be great: What happens when setting 9000 with IE 8 installed? What happens when setting 0 with IE 8 installed? Don’t forget to add Keys for Host Environments If you’re developing your application in Visual Studio and you run the debugger you may find that your application is still not rendering right, but if you run the actual generated EXE from Explorer or the OS command prompt it works. That’s because when you run the debugger in Visual Studio it wraps your application into a debugging host container. For this reason you might want to also add another registry key for yourapp.vshost.exe on your development machine. If you’re developing in Visual FoxPro make sure you add a key for vfp9.exe to see the rendering adjustments in the Visual FoxPro development environment. Cleaner HTML - no more HTML mangling! There are a number of additional benefits to setting up rendering of the Web Browser control to the IE 9 engine (or even the IE 8 engine) beyond the obvious rendering functionality. IE 9 actually returns your HTML in something that resembles the original HTML formatting, as opposed to the IE 7 default format which mangled the original HTML content. If you do the following in the WPF application: private void button2_Click(object sender, RoutedEventArgs e) { dynamic doc = this.webBrowser.Document; MessageBox.Show(doc.body.outerHtml); } you get different output depending on the rendering mode active. With the default IE 7 rendering you get: <BODY><DIV> <H1>Rounded Corners and Shadows - Creating Dialogs in CSS</H1> <DIV class=toolbarcontainer><A class=hoverbutton href="./"><IMG src="../../css/images/home.gif"> Home</A> <A class=hoverbutton href="RoundedCornersAndShadows.htm"><IMG src="../../css/images/refresh.gif"> Refresh</A> </DIV> <DIV class=containercontent> <FIELDSET><LEGEND>Plain Box</LEGEND><!-- Simple Box with rounded corners and shadow --> <DIV style="BORDER-BOTTOM: steelblue 2px solid; BORDER-LEFT: steelblue 2px solid; WIDTH: 550px; BORDER-TOP: steelblue 2px solid; BORDER-RIGHT: steelblue 2px solid" class="roundbox boxshadow"> <DIV style="BACKGROUND: khaki" class="boxcontenttext roundbox">Simple Rounded Corner Box. </DIV></DIV></FIELDSET> <FIELDSET><LEGEND>Box with Header</LEGEND> <DIV style="BORDER-BOTTOM: steelblue 2px solid; BORDER-LEFT: steelblue 2px solid; WIDTH: 550px; BORDER-TOP: steelblue 2px solid; BORDER-RIGHT: steelblue 2px solid" class="roundbox boxshadow"> <DIV class="gridheaderleft roundbox-top">Box with a Header</DIV> <DIV style="BACKGROUND: khaki" class="boxcontenttext roundbox-bottom">Simple Rounded Corner Box. </DIV></DIV></FIELDSET> <FIELDSET><LEGEND>Dialog Style Window</LEGEND> <DIV style="POSITION: relative; WIDTH: 450px" id=divDialog class="dialog boxshadow" jQuery16107208195684204002="2"> <DIV style="POSITION: relative" class=dialog-header> <DIV class=closebox></DIV>User Sign-in <DIV class=closebox jQuery16107208195684204002="3"></DIV></DIV> <DIV class=descriptionheader>This dialog is draggable and closable</DIV> <DIV class=dialog-content><LABEL>Username:</LABEL> <INPUT name=txtUsername value=" "> <LABEL>Password</LABEL> <INPUT name=txtPassword value=" "> <HR> <INPUT id=btnLogin value=Login type=button> </DIV> <DIV class=dialog-statusbar>Ready</DIV></DIV></FIELDSET> </DIV> <SCRIPT type=text/javascript>     $(document).ready(function () {         $("#divDialog")             .draggable({ handle: ".dialog-header" })             .closable({ handle: ".dialog-header",                 closeHandler: function () {                     alert("Window about to be closed.");                     return true;  // true closes - false leaves open                 }             });     }); </SCRIPT> </DIV></BODY> Now lest you think I’m out of my mind and create complete whacky HTML rooted in the last century, here’s the IE 9 rendering mode output which looks a heck of a lot cleaner and a lot closer to my original HTML of the page I’m accessing: <body> <div>         <h1>Rounded Corners and Shadows - Creating Dialogs in CSS</h1>     <div class="toolbarcontainer">         <a class="hoverbutton" href="./"> <img src="../../css/images/home.gif"> Home</a>         <a class="hoverbutton" href="RoundedCornersAndShadows.htm"> <img src="../../css/images/refresh.gif"> Refresh</a>     </div>         <div class="containercontent">     <fieldset>         <legend>Plain Box</legend>                <!-- Simple Box with rounded corners and shadow -->             <div style="border: 2px solid steelblue; width: 550px;" class="roundbox boxshadow">                              <div style="background: khaki;" class="boxcontenttext roundbox">                     Simple Rounded Corner Box.                 </div>             </div>     </fieldset>     <fieldset>         <legend>Box with Header</legend>         <div style="border: 2px solid steelblue; width: 550px;" class="roundbox boxshadow">                          <div class="gridheaderleft roundbox-top">Box with a Header</div>             <div style="background: khaki;" class="boxcontenttext roundbox-bottom">                 Simple Rounded Corner Box.             </div>         </div>     </fieldset>       <fieldset>         <legend>Dialog Style Window</legend>         <div style="width: 450px; position: relative;" id="divDialog" class="dialog boxshadow">             <div style="position: relative;" class="dialog-header">                 <div class="closebox"></div>                 User Sign-in             <div class="closebox"></div></div>             <div class="descriptionheader">This dialog is draggable and closable</div>                    <div class="dialog-content">                             <label>Username:</label>                 <input name="txtUsername" value=" " type="text">                 <label>Password</label>                 <input name="txtPassword" value=" " type="text">                                 <hr/>                                 <input id="btnLogin" value="Login" type="button">                        </div>             <div class="dialog-statusbar">Ready</div>         </div>     </fieldset>     </div> <script type="text/javascript">     $(document).ready(function () {         $("#divDialog")             .draggable({ handle: ".dialog-header" })             .closable({ handle: ".dialog-header",                 closeHandler: function () {                     alert("Window about to be closed.");                     return true;  // true closes - false leaves open                 }             });     }); </script>        </div> </body> IOW, in IE9 rendering mode IE9 is much closer (but not identical) to the original HTML from the page on the Web that we’re reading from. As a side note: Unfortunately, the browser feature emulation can't be applied against the Html Help (CHM) Engine in Windows which uses the Web Browser control (or COM interfaces anyway) to render Html Help content. I tried setting up hh.exe which is the help viewer, to use IE 9 rendering but a help file generated with CSS3 features will simply show in IE 7 mode. Bummer - this would have been a nice quick fix to allow help content served from CHM files to look better. HTML Editing leaves HTML formatting intact In the same vane, if you do any inline HTML editing in the control by setting content to be editable, IE 9’s control does a much more reasonable job of creating usable and somewhat valid HTML. It also leaves the original content alone other than the text your are editing or adding. No longer is the HTML output stripped of excess spaces and reformatted in IEs format. So if I do: private void button3_Click(object sender, RoutedEventArgs e) { dynamic doc = this.webBrowser.Document; doc.body.contentEditable = true; } and then make some changes to the document by typing into it using IE 9 mode, the document formatting stays intact and only the affected content is modified. The created HTML is reasonably clean (although it does lack proper XHTML formatting for things like <br/> <hr/>). This is very different from IE 7 mode which mangled the HTML as soon as the page was loaded into the control. Any editing you did stripped out all white space and lost all of your existing XHTML formatting. In IE 9 mode at least *most* of your original formatting stays intact. This is huge! In Html Help Builder I have supported HTML editing for a long time but the HTML mangling by the Web Browser control made it very difficult to edit the HTML later. Previously IE would mangle the HTML by stripping out spaces, upper casing all tags and converting many XHTML safe tags to its HTML 3 tags. Now IE leaves most of my document alone while editing, and creates cleaner and more compliant markup (with exception of self-closing elements like BR/HR). The end result is that I now have HTML editing in place that's much cleaner and actually capable of being manually edited. Caveats, Caveats, Caveats It wouldn't be Internet Explorer if there weren't some major compatibility issues involved in using this various browser version interaction. The biggest thing I ran into is that there are odd differences in some of the COM interfaces and what they return. I specifically ran into a problem with the document.selection.createRange() function which with IE 7 compatibility returns an expected text range object. When running in IE 8 or IE 9 mode however. I could not retrieve a valid text range with this code where loEdit is the WebBrowser control: loRange = loEdit.document.selection.CreateRange() The loRange object returned (here in FoxPro) had a length property of 0 but none of the other properties of the TextRange or TextRangeCollection objects were available. I figured this was due to some changed security settings but even after elevating the Intranet Security Zone and mucking with the other browser feature flags pertaining to security I had no luck. In the end I relented and used a JavaScript function in my editor document that returns a selection range object: function getselectionrange() { var range = document.selection.createRange(); return range; } and call that JavaScript function from my host applications code: *** Use a function in the document to get around HTML Editing issues loRange = loEdit.document.parentWindow.getselectionrange(.f.) and that does work correctly. This wasn't a big deal as I'm already loading a support script file into the editor page so all I had to do is add the function to this existing script file. You can find out more how to call script code in the Web Browser control from a host application in a previous post of mine. IE 8 and 9 also clamp down the security environment a little more than the default IE 7 control, so there may be other issues you run into. Other than the createRange() problem above I haven't seen anything else that is breaking in my code so far though and that's encouraging at least since it uses a lot of HTML document manipulation for the custom editor I've created (and would love to replace - any PROFESSIONAL alternatives anybody?) Registry Key Installation for your Application It’s important to remember that this registry setting is made per application, so most likely this is something you want to set up with your installer. Also remember that 32 and 64 bit settings require separate settings in the registry so if you’re creating your installer you most likely will want to set both keys in the registry preemptively for your application. I use Tarma Installer for all of my application installs and in Tarma I configure registry keys for both and set a flag to only install the latter key group in the 64 bit version: Because this setting is application specific you have to do this for every application you install unfortunately, but this also means that you can safely configure this setting in the registry because it is after only applied to your application. Another problem with install based installation is version detection. If IE 8 is installed I’d want 8000 for the value, if IE 9 is installed I want 9000. I can do this easily in code but in the installer this is much more difficult. I don’t have a good solution for this at the moment, but given that the app works with IE 7 mode now, IE 9 mode is just a bonus for the moment. If IE 9 is not installed and 9000 is used the default rendering will remain in use.   It sure would be nice if we could specify the IE rendering mode as a property, but I suspect the ActiveX container has to know before it loads what actual version to load up and once loaded can only load a single version of IE. This would account for this annoying application level configuration… Summary The registry feature emulation has been available for quite some time, but I just found out about it today and started experimenting around with it. I’m stoked to see that this is available as I’d pretty much given up in ever seeing any better rendering in the Web Browser control. Now at least my apps can take advantage of newer HTML features. Now if we could only get better HTML Editing support somehow <snicker>… ah can’t have everything.© Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  FoxPro  Windows  

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  • Using HTML 5 SessionState to save rendered Page Content

    - by Rick Strahl
    HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   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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  • Clustering for Mere Mortals (Pt2)

    - by Geoff N. Hiten
    Planning. I could stop there and let that be the entirety post #2 in this series.  Planning is the single most important element in building a cluster and the Laptop Demo Cluster is no exception.  One of the more awkward parts of actually creating a cluster is coordinating information between Windows Clustering and SQL Clustering.  The dialog boxes show up hours apart, but still have to have matching and consistent information. Excel seems to be a good tool for tracking these settings.  My workbook has four pages: Systems, Storage, Network, and Service Accounts.  The systems page looks like this:   Name Role Software Location East Physical Cluster Node 1 Windows Server 2008 R2 Enterprise Laptop VM West Physical Cluster Node 2 Windows Server 2008 R2 Enterprise Laptop VM North Physical Cluster Node 3 (Future Reserved) Windows Server 2008 R2 Enterprise Laptop VM MicroCluster Cluster Management Interface N/A Laptop VM SQL01 High-Performance High-Security Instance SQL Server 2008 Enterprise Edition x64 SP1 Laptop VM SQL02 High-Performance Standard-Security Instance SQL Server 2008 Enterprise Edition x64 SP1 Laptop VM SQL03 Standard-Performance High-Security Instance SQL Server 2008 Enterprise Edition x64 SP1 Laptop VM Note that everything that has a computer name is listed here, whether physical or virtual. Storage looks like this: Storage Name Instance Purpose Volume Path Size (GB) LUN ID Speed Quorum MicroCluster Cluster Quorum Quorum Q: 2     SQL01Anchor SQL01 Instance Anchor SQL01Anchor L: 2     SQL02Anchor SQL02 Instance Anchor SQL02Anchor M: 2     SQL01Data1 SQL01 SQL Data SQL01Data1 L:\MountPoints\SQL01Data1 2     SQL02Data1 SQL02 SQL Data SQL02Data1 M:\MountPoints\SQL02Data1       Starting at the left is the name used in the storage array.  It is important to rename resources at each level, whether it is Storage, LUN, Volume, or disk folder.  Otherwise, troubleshooting things gets complex and difficult.  You want to be able to glance at a resource at any level and see where it comes from and what it is connected to. Networking is the same way:   System Network VLAN  IP Subnet Mask Gateway DNS1 DNS2 East Public Cluster1 10.97.230.x(DHCP) 255.255.255.0 10.97.230.1 10.97.230.1 10.97.230.1 East Heartbeat Cluster2   255.255.255.0       West Public Cluster1 10.97.230.x(DHCP) 255.255.255.0 10.97.230.1 10.97.230.1 10.97.230.1 West Heartbeat Cluster2   255.255.255.0       North Public Cluster1 10.97.230.x(DHCP) 255.255.255.0 10.97.230.1 10.97.230.1 10.97.230.1 North Heartbeat Cluster2   255.255.255.0       SQL01 Public Cluster1 10.97.230.x(DHCP) 255.255.255.0       SQL02 Public Cluster1 10.97.230.x(DHCP) 255.255.255.0       One hallmark of a poorly planned and implemented cluster is a bunch of "Local Network Connection #n" entries in the network settings page.  That lets me know that somebody didn't care about the long-term supportabaility of the cluster.  This can be critically important with Hyper-V Clusters and their high NIC counts.  Final page:   Instance Service Name Account Password Domain OU SQL01 SQL Server SVCSQL01 Baseline22 MicroAD Service Accounts SQL01 SQL Agent SVCSQL01 Baseline22 MicroAD Service Accounts SQL02 SQL Server SVC_SQL02 Baseline22 MicroAD Service Accounts SQL02 SQL Agent SVC_SQL02 Baseline22 MicroAD Service Accounts SQL03 (Future) SQL Server SVC_SQL03 Baseline22 MicroAD Service Accounts SQL03 (Future) SQL Agent SVC_SQL03 Baseline22 MicroAD Service Accounts             Installation Account           administrator            Yes.  I write down the account information.  I secure the file via NTFS, but I don't want to fumble around looking for passwords when it comes time to rebuild a node. Always fill out the workbook COMPLETELY before installing anything.  The whole point is to have everything you need at your fingertips before you begin.  The install experience is so much better and more productive with this information in place.

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  • Vitality of Product Information Management Showcased at OpenWorld 2012

    - by Mala Narasimharajan
     By Sachin Patel Can you hear the countdown clock ticking!! OpenWorld 2012 is almost here and as I write this Oracle is buzzing with fresh new ideas and solutions that will be showcased this year. What an exciting time for all of us to be in midst of a digital revolution. Whether it is Apple fans clamoring to find every new feature that has been added to the iPhone 5 or a startup launching a new digital thermostat (has anyone looked at the new one from Nest ), product information is a vital for companies to grow and compete in this cut-throat market. Customer today struggle to aggregate and enrich this product data from the myriad of systems they have in place to run their businesses and operations. Having a product information strategy is paramount to align your sales channels and operations with the most accurate and upto date product data. We have a number of sessions this year at OpenWorld where you can gain more insight into how Oracle’s next generation of Fusion Applications, in this case Fusion Product Hub can provide you with a solution to streamline and get control of your Product Master Data. Enabling Trusted Enterprise Product Data with Oracle Fusion Product HubTuesday, October 2nd 11:45 am, Moscone West 2022 Join me Sachin Patel, Director of Product Strategy and Milan Bhatia, VP of Development as we discuss how you can enable trusted product master data in your enterprise. In this session we plan to cover the challenges companies face today in mastering product data. The discussion will also include how Fusion Product Hub brings new and innovative features to empower your product data owners to create a holistic and rich product definition that can be leveraged across your enterprise. We will also be joined by Pawel Fidelus from Fideltronik an Early Adopter for Fusion Product Hub who will showcase their plans to implement Fusion Product Hub and the value it will bring to Fideltronik Multichannel Fulfillment Excellence in Direct-to-Consumer Market Thursday, October 4th, 12:45 am, Moscone West 2024 Do you have multiple order capture systems? Do you have difficulty in fulfilling orders for your customers across various channels and suppliers? Mark Carson, Director, Fusion DOO and Brad Kerr, Director, AGSS will be showcasing the Fusion Distributed Order Orchestration solution and how companies can orchestrate orders from multiple order capture systems and route them to the appropriate fulfillment system. Sachin Patel, Director Product Strategy for Product MDM will highlight the business pain points in consolidating and commercializing data from a Multi Channel Commerce point of view and how Fusion Product Hub helps in allowing you to provide a single source of truth to drive a singular and rich customer experience. Oracle Fusion Supply Chain Management: Customer Adoption and Experiences                                                Wednesday, October 3rd 10:15 am, Moscone West 2003 This is a great session to attend to learn about how Fusion Supply Chain Management and Fusion Product Hub Early Adopters, including Boeing and Fideltronik are leveraging Fusion Applications to improve their Supply Chain operations. Have a great OpenWorld and see you soon!!

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  • Oracle OpenWorld Update: Oracle GoldenGate Customer Panels

    - by Doug Reid
    0 false 18 pt 18 pt 0 0 false false false /* 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-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} We are two weeks out from the start of Oracle OpenWorld 2012. The Data Integration team has a solid line-up of product and customer sessions for you to attend this year, plus five hands-on labs, and numerous demonstration pods in Moscone South. On Monday we kick the track off with Brad Adelberg’s Future Strategy, Direction and Roadmap for Oracle’s Data Integration Platform at 10:45AM in Moscone West 3005. Over the rest of the week we have a number of deep dive sessions that build out the themes that Brad discusses in his keynote, but the two that I would like to highlight today are our Oracle GoldenGate customer panels. The first customer panel is on Zero Downtime Operations and is on Monday at 1:45 in Moscone West 3005. The theme of this session is how to reduce downtime for critical must-succeed systems. Here’s a rundown of the session: Bank of America, TALX, and St. Jude Medical all have users communities that expect systems to be available around the clock. In this customer panel session, Bank of America discusses how it will be leveraging Oracle GoldenGate. St. Jude Medical shares how it is using Oracle GoldenGate to achieve a zero-downtime migration for a 5 TB Oracle online transaction processing (OLTP) 24/7 mission-critical database. TALX discusses how Equifax Workforce Information Services used Oracle GoldenGate to move from processing online transactions in a single site to processing concurrently from two geographically disparate data centers, providing a highly available solution with significant burst capacity. On Tuesday at 11:45 in Moscone West 3005 we switch gears and host a customer panel on Operational Reporting. The theme of this customer panel is all around reporting and how Oracle GoldenGate raises the bar on reporting by enabling real-time access to real-time data. Here’s a rundown of the session: Turk Telekom and Comcast are half a world away from each other, but these two powerhouse companies have both drastically improved performance and access to real-time data by using Oracle GoldenGate. During this panel discussion, Turk Telekom will explain its evaluation and implementation of Oracle GoldenGate, how the business has experienced significant improvements in the core database and reporting platform, and how it plans to expand its usage into its SOA architecture and its architecture based on Oracle’s Siebel platform. Comcast will explain its implementation of Oracle GoldenGate and how it moves data in real time from its mission-critical HP NonStop database to a Teradata data warehouse. Join us at our sessions to learn what other customers are doing with our products or stop by our demo pods in Moscone south and meet the product management and development teams.

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  • Autodetect timezone in Rails given UTC offset and DST

    - by Jose
    I basically want to autodetect a user's timezone using Rails. I can use this JS code at the user's browser (http://www.onlineaspect.com/2007/06/08/auto-detect-a-time-zone-with-javascript/) to send a form with the UTC offset and the fact that the time zone observes DST during summer or not, in the user's time zone. Once I have that info in the server, I want to select the matching time zone. In Rails, I can get a list of time zones with ActiveSupport::TimeZone.all. Also, I can filter zones by utf offset thanks to the utc_offset method. However, I don't know how to filter the timezones that do/don't observe DST. E.g. suppose a user lives in Amsterdam. Filtering by UTC offset will return Berlin, Belgrado, Madrid, etc timezones, as well as West Central Africa. All of them, but West Central Africa, would be appropriate timezones for a user in Amsterdam (as they provide the same time/date), but I need to filter West Central Africa, which does not perform DST in summer. How can I do this in Rails? Also, are any of my assumptions wrong?

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  • How to populate Range variable from a Sub/Function call?

    - by Ken Ingram
    I am trying to get this sub to work but the operationalRange variable is not being assigned. Despite the fact that the function selectBodyRow(bodyName) works fine. Sub sortRows(bodyName As String, ByRef wksht As Worksheet) Dim operationalRange As Range Set operationalRange = selectBodyRow(bodyName) Debug.Print "Sorting Worksheet: " & wksht.Name If Not operationalRange Is Nothing Then operationalRange.Select Debug.Print "Sorting " & operationalRange.Count & "Rows." ActiveWorkbook.Worksheets(wksht.Name).Sort.SortFields.Clear ActiveWorkbook.Worksheets(wksht.Name).Sort.SortFields.Add Key:=operationalRange, _ SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal ActiveWorkbook.Worksheets(wksht.Name).Sort.SortFields.Add Key:=operationalRange, _ SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal With ActiveWorkbook.Worksheets(wksht.Name).Sort .SetRange operationalRange .Header = xlGuess .MatchCase = False .Orientation = xlTopToBottom .SortMethod = xlPinYin .Apply End With Else MsgBox "Body is not being Set" End If End Sub The Sub being called by the above Sub is: Function selectBodyRow(bodyName As String) As Range Dim rangeStart As String, rangeEnd As String Dim selectionStart As Range, selectionEnd As Range Dim result As Range, srchRng As Range, cngrs As Variant If bodyName = "WEST" Then rangeStart = "<-WEST START->" rangeEnd = "<-WEST END->" ElseIf bodyName = "EAST" Then rangeStart = "<-EAST START->" rangeEnd = "<-EAST END->" End If Set srchRng = Range("A:A") srchRng.Select Set selectionStart = srchRng.Find(What:=rangeStart, After:=ActiveCell, LookIn _ :=xlValues, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:= _ xlNext, MatchCase:=False, SearchFormat:=False) Set selectionEnd = srchRng.Find(What:=rangeEnd, After:=ActiveCell, LookIn _ :=xlValues, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:= _ xlNext, MatchCase:=False, SearchFormat:=False) Set result = Range(selectionStart.Offset(1, 0), selectionEnd.Offset(-1, 0)) result.EntireRow.Select End Function

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  • An Introduction to ASP.NET Web API

    - by Rick Strahl
    Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in 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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  • LSI 9285-8e and Supermicro SC837E26-RJBOD1 duplicate enclosure ID and slot numbers

    - by Andy Shinn
    I am working with 2 x Supermicro SC837E26-RJBOD1 chassis connected to a single LSI 9285-8e card in a Supermicro 1U host. There are 28 drives in each chassis for a total of 56 drives in 28 RAID1 mirrors. The problem I am running in to is that there are duplicate slots for the 2 chassis (the slots list twice and only go from 0 to 27). All the drives also show the same enclosure ID (ID 36). However, MegaCLI -encinfo lists the 2 enclosures correctly (ID 36 and ID 65). My question is, why would this happen? Is there an option I am missing to use 2 enclosures effectively? This is blocking me rebuilding a drive that failed in slot 11 since I can only specify enclosure and slot as parameters to replace a drive. When I do this, it picks the wrong slot 11 (device ID 46 instead of device ID 19). Adapter #1 is the LSI 9285-8e, adapter #0 (which I removed due to space limitations) is the onboard LSI. Adapter information: Adapter #1 ============================================================================== Versions ================ Product Name : LSI MegaRAID SAS 9285-8e Serial No : SV12704804 FW Package Build: 23.1.1-0004 Mfg. Data ================ Mfg. Date : 06/30/11 Rework Date : 00/00/00 Revision No : 00A Battery FRU : N/A Image Versions in Flash: ================ BIOS Version : 5.25.00_4.11.05.00_0x05040000 WebBIOS Version : 6.1-20-e_20-Rel Preboot CLI Version: 05.01-04:#%00001 FW Version : 3.140.15-1320 NVDATA Version : 2.1106.03-0051 Boot Block Version : 2.04.00.00-0001 BOOT Version : 06.253.57.219 Pending Images in Flash ================ None PCI Info ================ Vendor Id : 1000 Device Id : 005b SubVendorId : 1000 SubDeviceId : 9285 Host Interface : PCIE ChipRevision : B0 Number of Frontend Port: 0 Device Interface : PCIE Number of Backend Port: 8 Port : Address 0 5003048000ee8e7f 1 5003048000ee8a7f 2 0000000000000000 3 0000000000000000 4 0000000000000000 5 0000000000000000 6 0000000000000000 7 0000000000000000 HW Configuration ================ SAS Address : 500605b0038f9210 BBU : Present Alarm : Present NVRAM : Present Serial Debugger : Present Memory : Present Flash : Present Memory Size : 1024MB TPM : Absent On board Expander: Absent Upgrade Key : Absent Temperature sensor for ROC : Present Temperature sensor for controller : Absent ROC temperature : 70 degree Celcius Settings ================ Current Time : 18:24:36 3/13, 2012 Predictive Fail Poll Interval : 300sec Interrupt Throttle Active Count : 16 Interrupt Throttle Completion : 50us Rebuild Rate : 30% PR Rate : 30% BGI Rate : 30% Check Consistency Rate : 30% Reconstruction Rate : 30% Cache Flush Interval : 4s Max Drives to Spinup at One Time : 2 Delay Among Spinup Groups : 12s Physical Drive Coercion Mode : Disabled Cluster Mode : Disabled Alarm : Enabled Auto Rebuild : Enabled Battery Warning : Enabled Ecc Bucket Size : 15 Ecc Bucket Leak Rate : 1440 Minutes Restore HotSpare on Insertion : Disabled Expose Enclosure Devices : Enabled Maintain PD Fail History : Enabled Host Request Reordering : Enabled Auto Detect BackPlane Enabled : SGPIO/i2c SEP Load Balance Mode : Auto Use FDE Only : No Security Key Assigned : No Security Key Failed : No Security Key Not Backedup : No Default LD PowerSave Policy : Controller Defined Maximum number of direct attached drives to spin up in 1 min : 10 Any Offline VD Cache Preserved : No Allow Boot with Preserved Cache : No Disable Online Controller Reset : No PFK in NVRAM : No Use disk activity for locate : No Capabilities ================ RAID Level Supported : RAID0, RAID1, RAID5, RAID6, RAID00, RAID10, RAID50, RAID60, PRL 11, PRL 11 with spanning, SRL 3 supported, PRL11-RLQ0 DDF layout with no span, PRL11-RLQ0 DDF layout with span Supported Drives : SAS, SATA Allowed Mixing: Mix in Enclosure Allowed Mix of SAS/SATA of HDD type in VD Allowed Status ================ ECC Bucket Count : 0 Limitations ================ Max Arms Per VD : 32 Max Spans Per VD : 8 Max Arrays : 128 Max Number of VDs : 64 Max Parallel Commands : 1008 Max SGE Count : 60 Max Data Transfer Size : 8192 sectors Max Strips PerIO : 42 Max LD per array : 16 Min Strip Size : 8 KB Max Strip Size : 1.0 MB Max Configurable CacheCade Size: 0 GB Current Size of CacheCade : 0 GB Current Size of FW Cache : 887 MB Device Present ================ Virtual Drives : 28 Degraded : 0 Offline : 0 Physical Devices : 59 Disks : 56 Critical Disks : 0 Failed Disks : 0 Supported Adapter Operations ================ Rebuild Rate : Yes CC Rate : Yes BGI Rate : Yes Reconstruct Rate : Yes Patrol Read Rate : Yes Alarm Control : Yes Cluster Support : No BBU : No Spanning : Yes Dedicated Hot Spare : Yes Revertible Hot Spares : Yes Foreign Config Import : Yes Self Diagnostic : Yes Allow Mixed Redundancy on Array : No Global Hot Spares : Yes Deny SCSI Passthrough : No Deny SMP Passthrough : No Deny STP Passthrough : No Support Security : No Snapshot Enabled : No Support the OCE without adding drives : Yes Support PFK : Yes Support PI : No Support Boot Time PFK Change : Yes Disable Online PFK Change : No PFK TrailTime Remaining : 0 days 0 hours Support Shield State : Yes Block SSD Write Disk Cache Change: Yes Supported VD Operations ================ Read Policy : Yes Write Policy : Yes IO Policy : Yes Access Policy : Yes Disk Cache Policy : Yes Reconstruction : Yes Deny Locate : No Deny CC : No Allow Ctrl Encryption: No Enable LDBBM : No Support Breakmirror : No Power Savings : Yes Supported PD Operations ================ Force Online : Yes Force Offline : Yes Force Rebuild : Yes Deny Force Failed : No Deny Force Good/Bad : No Deny Missing Replace : No Deny Clear : No Deny Locate : No Support Temperature : Yes Disable Copyback : No Enable JBOD : No Enable Copyback on SMART : No Enable Copyback to SSD on SMART Error : Yes Enable SSD Patrol Read : No PR Correct Unconfigured Areas : Yes Enable Spin Down of UnConfigured Drives : Yes Disable Spin Down of hot spares : No Spin Down time : 30 T10 Power State : Yes Error Counters ================ Memory Correctable Errors : 0 Memory Uncorrectable Errors : 0 Cluster Information ================ Cluster Permitted : No Cluster Active : No Default Settings ================ Phy Polarity : 0 Phy PolaritySplit : 0 Background Rate : 30 Strip Size : 64kB Flush Time : 4 seconds Write Policy : WB Read Policy : Adaptive Cache When BBU Bad : Disabled Cached IO : No SMART Mode : Mode 6 Alarm Disable : Yes Coercion Mode : None ZCR Config : Unknown Dirty LED Shows Drive Activity : No BIOS Continue on Error : No Spin Down Mode : None Allowed Device Type : SAS/SATA Mix Allow Mix in Enclosure : Yes Allow HDD SAS/SATA Mix in VD : Yes Allow SSD SAS/SATA Mix in VD : No Allow HDD/SSD Mix in VD : No Allow SATA in Cluster : No Max Chained Enclosures : 16 Disable Ctrl-R : Yes Enable Web BIOS : Yes Direct PD Mapping : No BIOS Enumerate VDs : Yes Restore Hot Spare on Insertion : No Expose Enclosure Devices : Yes Maintain PD Fail History : Yes Disable Puncturing : No Zero Based Enclosure Enumeration : No PreBoot CLI Enabled : Yes LED Show Drive Activity : Yes Cluster Disable : Yes SAS Disable : No Auto Detect BackPlane Enable : SGPIO/i2c SEP Use FDE Only : No Enable Led Header : No Delay during POST : 0 EnableCrashDump : No Disable Online Controller Reset : No EnableLDBBM : No Un-Certified Hard Disk Drives : Allow Treat Single span R1E as R10 : No Max LD per array : 16 Power Saving option : Don't Auto spin down Configured Drives Max power savings option is not allowed for LDs. Only T10 power conditions are to be used. Default spin down time in minutes: 30 Enable JBOD : No TTY Log In Flash : No Auto Enhanced Import : No BreakMirror RAID Support : No Disable Join Mirror : No Enable Shield State : Yes Time taken to detect CME : 60s Exit Code: 0x00 Enclosure information: # /opt/MegaRAID/MegaCli/MegaCli64 -encinfo -a1 Number of enclosures on adapter 1 -- 3 Enclosure 0: Device ID : 36 Number of Slots : 28 Number of Power Supplies : 2 Number of Fans : 3 Number of Temperature Sensors : 1 Number of Alarms : 1 Number of SIM Modules : 0 Number of Physical Drives : 28 Status : Normal Position : 1 Connector Name : Port B Enclosure type : SES VendorId is LSI CORP and Product Id is SAS2X36 VendorID and Product ID didnt match FRU Part Number : N/A Enclosure Serial Number : N/A ESM Serial Number : N/A Enclosure Zoning Mode : N/A Partner Device Id : 65 Inquiry data : Vendor Identification : LSI CORP Product Identification : SAS2X36 Product Revision Level : 0718 Vendor Specific : x36-55.7.24.1 Number of Voltage Sensors :2 Voltage Sensor :0 Voltage Sensor Status :OK Voltage Value :5020 milli volts Voltage Sensor :1 Voltage Sensor Status :OK Voltage Value :11820 milli volts Number of Power Supplies : 2 Power Supply : 0 Power Supply Status : OK Power Supply : 1 Power Supply Status : OK Number of Fans : 3 Fan : 0 Fan Speed :Low Speed Fan Status : OK Fan : 1 Fan Speed :Low Speed Fan Status : OK Fan : 2 Fan Speed :Low Speed Fan Status : OK Number of Temperature Sensors : 1 Temp Sensor : 0 Temperature : 48 Temperature Sensor Status : OK Number of Chassis : 1 Chassis : 0 Chassis Status : OK Enclosure 1: Device ID : 65 Number of Slots : 28 Number of Power Supplies : 2 Number of Fans : 3 Number of Temperature Sensors : 1 Number of Alarms : 1 Number of SIM Modules : 0 Number of Physical Drives : 28 Status : Normal Position : 1 Connector Name : Port A Enclosure type : SES VendorId is LSI CORP and Product Id is SAS2X36 VendorID and Product ID didnt match FRU Part Number : N/A Enclosure Serial Number : N/A ESM Serial Number : N/A Enclosure Zoning Mode : N/A Partner Device Id : 36 Inquiry data : Vendor Identification : LSI CORP Product Identification : SAS2X36 Product Revision Level : 0718 Vendor Specific : x36-55.7.24.1 Number of Voltage Sensors :2 Voltage Sensor :0 Voltage Sensor Status :OK Voltage Value :5020 milli volts Voltage Sensor :1 Voltage Sensor Status :OK Voltage Value :11760 milli volts Number of Power Supplies : 2 Power Supply : 0 Power Supply Status : OK Power Supply : 1 Power Supply Status : OK Number of Fans : 3 Fan : 0 Fan Speed :Low Speed Fan Status : OK Fan : 1 Fan Speed :Low Speed Fan Status : OK Fan : 2 Fan Speed :Low Speed Fan Status : OK Number of Temperature Sensors : 1 Temp Sensor : 0 Temperature : 47 Temperature Sensor Status : OK Number of Chassis : 1 Chassis : 0 Chassis Status : OK Enclosure 2: Device ID : 252 Number of Slots : 8 Number of Power Supplies : 0 Number of Fans : 0 Number of Temperature Sensors : 0 Number of Alarms : 0 Number of SIM Modules : 1 Number of Physical Drives : 0 Status : Normal Position : 1 Connector Name : Unavailable Enclosure type : SGPIO Failed in first Inquiry commnad FRU Part Number : N/A Enclosure Serial Number : N/A ESM Serial Number : N/A Enclosure Zoning Mode : N/A Partner Device Id : Unavailable Inquiry data : Vendor Identification : LSI Product Identification : SGPIO Product Revision Level : N/A Vendor Specific : Exit Code: 0x00 Now, notice that each slot 11 device shows an enclosure ID of 36, I think this is where the discrepancy happens. One should be 36. But the other should be on enclosure 65. Drives in slot 11: Enclosure Device ID: 36 Slot Number: 11 Drive's postion: DiskGroup: 5, Span: 0, Arm: 1 Enclosure position: 0 Device Id: 48 WWN: Sequence Number: 11 Media Error Count: 0 Other Error Count: 0 Predictive Failure Count: 0 Last Predictive Failure Event Seq Number: 0 PD Type: SATA Raw Size: 2.728 TB [0x15d50a3b0 Sectors] Non Coerced Size: 2.728 TB [0x15d40a3b0 Sectors] Coerced Size: 2.728 TB [0x15d400000 Sectors] Firmware state: Online, Spun Up Is Commissioned Spare : YES Device Firmware Level: A5C0 Shield Counter: 0 Successful diagnostics completion on : N/A SAS Address(0): 0x5003048000ee8a53 Connected Port Number: 1(path0) Inquiry Data: MJ1311YNG6YYXAHitachi HDS5C3030ALA630 MEAOA5C0 FDE Enable: Disable Secured: Unsecured Locked: Unlocked Needs EKM Attention: No Foreign State: None Device Speed: 6.0Gb/s Link Speed: 6.0Gb/s Media Type: Hard Disk Device Drive Temperature :30C (86.00 F) PI Eligibility: No Drive is formatted for PI information: No PI: No PI Drive's write cache : Disabled Drive's NCQ setting : Enabled Port-0 : Port status: Active Port's Linkspeed: 6.0Gb/s Drive has flagged a S.M.A.R.T alert : No Enclosure Device ID: 36 Slot Number: 11 Drive's postion: DiskGroup: 19, Span: 0, Arm: 1 Enclosure position: 0 Device Id: 19 WWN: Sequence Number: 4 Media Error Count: 0 Other Error Count: 0 Predictive Failure Count: 0 Last Predictive Failure Event Seq Number: 0 PD Type: SATA Raw Size: 2.728 TB [0x15d50a3b0 Sectors] Non Coerced Size: 2.728 TB [0x15d40a3b0 Sectors] Coerced Size: 2.728 TB [0x15d400000 Sectors] Firmware state: Online, Spun Up Is Commissioned Spare : NO Device Firmware Level: A580 Shield Counter: 0 Successful diagnostics completion on : N/A SAS Address(0): 0x5003048000ee8e53 Connected Port Number: 0(path0) Inquiry Data: MJ1313YNG1VA5CHitachi HDS5C3030ALA630 MEAOA580 FDE Enable: Disable Secured: Unsecured Locked: Unlocked Needs EKM Attention: No Foreign State: None Device Speed: 6.0Gb/s Link Speed: 6.0Gb/s Media Type: Hard Disk Device Drive Temperature :30C (86.00 F) PI Eligibility: No Drive is formatted for PI information: No PI: No PI Drive's write cache : Disabled Drive's NCQ setting : Enabled Port-0 : Port status: Active Port's Linkspeed: 6.0Gb/s Drive has flagged a S.M.A.R.T alert : No Update 06/28/12: I finally have some new information about (what we think) the root cause of this problem so I thought I would share. After getting in contact with a very knowledgeable Supermicro tech, they provided us with a tool called Xflash (doesn't appear to be readily available on their FTP). When we gathered some information using this utility, my colleague found something very strange: root@mogile2 test]# ./xflash.dat -i get avail Initializing Interface. Expander: SAS2X36 (SAS2x36) 1) SAS2X36 (SAS2x36) (50030480:00EE917F) (0.0.0.0) 2) SAS2X36 (SAS2x36) (50030480:00E9D67F) (0.0.0.0) 3) SAS2X36 (SAS2x36) (50030480:0112D97F) (0.0.0.0) This lists the connected enclosures. You see the 3 connected (we have since added a 3rd and a 4th which is not yet showing up) with their respective SAS address / WWN (50030480:00EE917F). Now we can use this address to get information on the individual enclosures: [root@mogile2 test]# ./xflash.dat -i 5003048000EE917F get exp Initializing Interface. Expander: SAS2X36 (SAS2x36) Reading the expander information.......... Expander: SAS2X36 (SAS2x36) B3 SAS Address: 50030480:00EE917F Enclosure Logical Id: 50030480:0000007F IP Address: 0.0.0.0 Component Identifier: 0x0223 Component Revision: 0x05 [root@mogile2 test]# ./xflash.dat -i 5003048000E9D67F get exp Initializing Interface. Expander: SAS2X36 (SAS2x36) Reading the expander information.......... Expander: SAS2X36 (SAS2x36) B3 SAS Address: 50030480:00E9D67F Enclosure Logical Id: 50030480:0000007F IP Address: 0.0.0.0 Component Identifier: 0x0223 Component Revision: 0x05 [root@mogile2 test]# ./xflash.dat -i 500304800112D97F get exp Initializing Interface. Expander: SAS2X36 (SAS2x36) Reading the expander information.......... Expander: SAS2X36 (SAS2x36) B3 SAS Address: 50030480:0112D97F Enclosure Logical Id: 50030480:0112D97F IP Address: 0.0.0.0 Component Identifier: 0x0223 Component Revision: 0x05 Did you catch it? The first 2 enclosures logical ID is partially masked out where the 3rd one (which has a correct unique enclosure ID) is not. We pointed this out to Supermicro and were able to confirm that this address is supposed to be set during manufacturing and there was a problem with a certain batch of these enclosures where the logical ID was not set. We believe that the RAID controller is determining the ID based on the logical ID and since our first 2 enclosures have the same logical ID, they get the same enclosure ID. We also confirmed that 0000007F is the default which comes from LSI as an ID. The next pointer that helps confirm this could be a manufacturing problem with a run of JBODs is the fact that all 6 of the enclosures that have this problem begin with 00E. I believe that between 00E8 and 00EE Supermicro forgot to program the logical IDs correctly and neglected to recall or fix the problem post production. Fortunately for us, there is a tool to manage the WWN and logical ID of the devices from Supermicro: ftp://ftp.supermicro.com/utility/ExpanderXtools_Lite/. Our next step is to schedule a shutdown of these JBODs (after data migration) and reprogram the logical ID and see if it solves the problem. Update 06/28/12 #2: I just discovered this FAQ at Supermicro while Google searching for "lsi 0000007f": http://www.supermicro.com/support/faqs/faq.cfm?faq=11805. I still don't understand why, in the last several times we contacted Supermicro, they would have never directed us to this article :\

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  • Can I delete EFI System Partition without harming other data on drive?

    - by Andy
    I have three external HDD's in a USB enclosure. After a recent upgrade to Win7, during which these three drives were actually installed inside the PC tower, two of the three drives now have a 200MB EFI partition, and the two drives do not show up as usable drives under either Win7 or Snow Leopard. One of the drives is empty; the other one, however, has a bunch of stuff on it that I want to save if possible. My question is, how can I get back to this data? Can I simply delete the EFI partition, and all will be well? Or do I have to do something trickier? Or am I just hosed?

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  • Chroot within chroot

    - by Andy
    I'm using Centos 5.2 and when I try to make a chroot jail using the script, I get: Copying libraries for /usr/bin/scp. (0x00007fff17bfe000) cp: cannot stat `(0x00007fff17bfe000)': No such file or directory ... I am currently using on a rackspace cloud server so i suspect that these dependencies are outside of my own root. Does anyone have a better idea for jailing the sftp server on a cloud server using Centos 5.2?

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  • Varnish VCL Reload Fails After Adding Second Backend

    - by Andy
    I have been running Varnish on my production server successfully for several weeks now. Now I'm trying to configure Varnish to use a second backend for certain requests. My original working VCL (/etc/varnish/default.vcl) begins like this: backend default { .host = "127.0.0.1"; .port = "8080"; } ...rest of VCL... And I'm changing it to: backend default { .host = "127.0.0.1"; .port = "8080"; } backend backend2 { .host = "12.34.56.78"; .port = "80"; } ...rest of VCL... When I reload the VCL file, I get the following: Command failed with error code 106 Failed to reload /etc/varnish/default.vcl. Any idea what the error could be, or how I can get more information on the problem?

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  • Is anyone using KVM in production?

    - by Andy Shellam
    I've been trying to set up a pair of servers utilising KVM on Ubuntu 9.10 to host 8 virtual machines between them and ended up with various issues from the VMs freezing, to not powering on. I had one virtual server set up and running and was setting up a second, when any operation involving OpenSSL would cause the VM to lock up in a weird way - all network traffic would cease, it wouldn't process logins on the console, but it wasn't taking any CPU time off the host. The first virtual server was identical and worked perfectly. Another VM I tried to setup had installed Ubuntu fine then refused to reboot, throwing kernel exceptions to do with XFS. I've now installed Citrix XenServer 5.5 on both hosts, and am now setting up my third VM with absolutely no issues. I also had the same experience when I tried VMware, but I preferred Xen as it appears to give more features on the free license. My question is am I just unlucky with KVM, or is KVM as unstable as it appears? Are you using, or planning on using, KVM in production, and how successful have you been?

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  • Windows Server 2008 x86 Services for Unix SDK (SUA) RSH

    - by Andy Arismendi
    Running RSH commands on a Windows box against a Linux box works only for the administrator user. Is there a file somewhere that has a list of users that can run commands remotely? More Info The server configuration is automated by VMware's product... There's no /etc/hosts.equiv file setup but there is a /root/.rhosts file with an entry of [IP ADDRESS] +. The SUA client C:\Windows\SUA\bin\rsh can login when run as the local administrator account but no other user can login. The error is: rcmd: unknown user: [username]. The command I'm trying to run is: rsh -l root [IP ADDRESS] ls.

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  • Why aren't RemoteApp icons showing up

    - by Andy Schneider
    I have a Windows 2008 R2 server running RDS. I have installed and configured RemoteApp to publish applications with RDS Web Access. When I browse to https://servernname.domain.local/RDWeb I can log in and get to the RemoteApp Programs tab, but there are no icons or apps to click on. I have added a bunch of apps in Remote App manager and they are all enabled for RD Web Access. Also, I am an administrator on the server.

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  • IIS URL Rewrite HTTP to HTTPS with Port

    - by Andy Arismendi
    My website has two bindings: 1000 and 1443 (port 80/443 are in use by another website on the same IIS instance). Port 1000 is HTTP, port 1443 is HTTPS. What I want to do is redirect any incoming request using "htt p://server:1000" to "htt ps://server:1443". I'm playing around with IIS 7 rewrite module 2.0 but I'm banging my head against the wall. Any insight is appreciated! BTW the rewrite configuration below works great with a site that has an HTTP binding on port 80 and HTTPS binding on port 443, but it doesn't work with my ports. P.S. My URLs intentionally have spaces because the 'spam prevention mechanism' kicked in. For some reason google login doesn't work anymore so I had to create an OpenID account (No Script could be the culprit). I'm not sure how to get XML to display nicely so I added spaces after the opening brackets. < ?xml version="1.0" encoding="utf-8"? < configuration < system.webServer < rewrite < rules < rule name="HTTP to HTTPS redirect" stopProcessing="true" < match url="(.*)" / < conditions trackAllCaptures="true" < add input="{HTTPS}" pattern="off" / < /conditions < action type="Redirect" redirectType="Found" url="htt ps: // {HTTP_HOST}/{R:1}" / < /rule < /rules < /rewrite < /system.webServer < /configuration

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  • Rails, Capistrano, Nginx, Unicorn - Application has been already initialized (RuntimeError)

    - by Andy Copley
    Can anyone shed some light on what exactly this error refers to? I'm having trouble deploying new versions of the site. I, INFO -- : reloading config_file=[snip]/current/config/unicorn.rb I, INFO -- : Refreshing Gem list E, ERROR -- : error reloading config_file=[snip]/current/config/unicorn.rb: Application has been already initialized. (RuntimeError) E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/railties-3.2.3/lib/rails/application.rb:135:in `initialize!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/railties-3.2.3/lib/rails/railtie/configurable.rb:30:in `method_missing' E, ERROR -- : [snip]/releases/20120907085937/config/environment.rb:5:in `<top (required)>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `block in require' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:236:in `load_dependency' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require' E, ERROR -- : config.ru:4:in `block in <main>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize' E, ERROR -- : config.ru:1:in `new' E, ERROR -- : config.ru:1:in `<main>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn.rb:44:in `eval' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn.rb:44:in `block in builder' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:696:in `call' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:696:in `build_app!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:677:in `load_config!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:303:in `join' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/bin/unicorn:121:in `<top (required)>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/bin/unicorn:23:in `load' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/bin/unicorn:23:in `<main>' I, INFO -- : reaped #<Process::Status: pid 3182 exit 0> worker=0 I, INFO -- : reaped #<Process::Status: pid 3185 exit 0> worker=1 I, INFO -- : reaped #<Process::Status: pid 3188 exit 0> worker=2 I, INFO -- : reaped #<Process::Status: pid 3191 exit 0> worker=3 I, INFO -- : worker=0 ready I, INFO -- : worker=3 ready I, INFO -- : worker=1 ready I, INFO -- : worker=2 ready Unicorn.rb root = "/home/[user]/apps/[site]/current" working_directory root pid "#{root}/tmp/pids/unicorn.pid" stderr_path "#{root}/log/unicorn.log" stdout_path "#{root}/log/unicorn.log" listen "/tmp/unicorn.[site].sock", :backlog => 2048 worker_processes 4 preload_app true timeout 30 before_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect! end after_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection end Any help appreciated - I can pull more config files if required.

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  • Do all Mac OS X applications require Admin permissions to 'install'?

    - by Andy
    I'm new to the whole Mac OS X operating system. I'm trying to learn and I've got myself a MacBook running Mac OS X 10.7.3. I've created a test user that can not administrate so that I can test out permissions and I've found that I can not do anything in the Applications folder, which includes 'installing' applications (even those drag 'n' drop ones) and creating folders, without entering an Admin name and password. However, I was under the impression that this wasn't the case and you only needed Admin permissions to write to somewhere like Preferences, so can somebody please clarify why it is asking for Admin when I try to drag 'n' drop applications into the Applications folder.

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  • How to lock Windows7 from installing anything.

    - by Andy
    A family member continually needs me to reinstall his PC after it gets viruses and spyware. He claims that he never downloads anything but evidence suggests otherwise. Unless there is some way that watching 'videos' can get spyware on there. AFAIK the computer is kept up to date. Possible solutions? Make a login where its impossible for him to install anything. Windows 7 standard account doesn't appear to be enough. Is a standard account enough here? I tried this once before and he still seemed to get IE toolbars installed up the wazoo Somehow make an automated image where if he 'messes up' or even on log off the computer restores the whole drive image. Similar to what I've seen in Kinko's Something I've not thought of.... And I know you are all going to say 'stop fixing it you are an enabler'... yes I know but I'm not going to have another fight with my wife over helping her family... right now I'm doing this to keep her happy not the idiot with the 'video' addiction ;-) So the name of the game is minimizing my overhead.

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  • How to configure emacs by using this file?

    - by Andy Leman
    From http://public.halogen-dg.com/browser/alex-emacs-settings/.emacs?rev=1346 I got: (setq load-path (cons "/home/alex/.emacs.d/" load-path)) (setq load-path (cons "/home/alex/.emacs.d/configs/" load-path)) (defconst emacs-config-dir "~/.emacs.d/configs/" "") (defun load-cfg-files (filelist) (dolist (file filelist) (load (expand-file-name (concat emacs-config-dir file))) (message "Loaded config file:%s" file) )) (load-cfg-files '("cfg_initsplit" "cfg_variables_and_faces" "cfg_keybindings" "cfg_site_gentoo" "cfg_conf-mode" "cfg_mail-mode" "cfg_region_hooks" "cfg_apache-mode" "cfg_crontab-mode" "cfg_gnuserv" "cfg_subversion" "cfg_css-mode" "cfg_php-mode" "cfg_tramp" "cfg_killbuffer" "cfg_color-theme" "cfg_uniquify" "cfg_tabbar" "cfg_python" "cfg_ack" "cfg_scpaste" "cfg_ido-mode" "cfg_javascript" "cfg_ange_ftp" "cfg_font-lock" "cfg_default_face" "cfg_ecb" "cfg_browser" "cfg_orgmode" ; "cfg_gnus" ; "cfg_cyrillic" )) ; enable disabled advanced features (put 'downcase-region 'disabled nil) (put 'scroll-left 'disabled nil) (put 'upcase-region 'disabled nil) ; narrow cursor ;(setq-default cursor-type 'hbar) (cua-mode) ; highlight current line (global-hl-line-mode 1) ; AV: non-aggressive scrolling (setq scroll-conservatively 100) (setq scroll-preserve-screen-position 't) (setq scroll-margin 0) (custom-set-variables ;; custom-set-variables was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won't work right. '(ange-ftp-passive-host-alist (quote (("redbus2.chalkface.com" . "on") ("zope.halogen-dg.com" . "on") ("85.119.217.50" . "on")))) '(blink-cursor-mode nil) '(browse-url-browser-function (quote browse-url-firefox)) '(browse-url-new-window-flag t) '(buffers-menu-max-size 30) '(buffers-menu-show-directories t) '(buffers-menu-show-status nil) '(case-fold-search t) '(column-number-mode t) '(cua-enable-cua-keys nil) '(user-mail-address "[email protected]") '(cua-mode t nil (cua-base)) '(current-language-environment "UTF-8") '(file-name-shadow-mode t) '(fill-column 79) '(grep-command "grep --color=never -nHr -e * | grep -v .svn --color=never") '(grep-use-null-device nil) '(inhibit-startup-screen t) '(initial-frame-alist (quote ((width . 80) (height . 40)))) '(initsplit-customizations-alist (quote (("tabbar" "configs/cfg_tabbar.el" t) ("ecb" "configs/cfg_ecb.el" t) ("ange\\-ftp" "configs/cfg_ange_ftp.el" t) ("planner" "configs/cfg_planner.el" t) ("dired" "configs/cfg_dired.el" t) ("font\\-lock" "configs/cfg_font-lock.el" t) ("speedbar" "configs/cfg_ecb.el" t) ("muse" "configs/cfg_muse.el" t) ("tramp" "configs/cfg_tramp.el" t) ("uniquify" "configs/cfg_uniquify.el" t) ("default" "configs/cfg_font-lock.el" t) ("ido" "configs/cfg_ido-mode.el" t) ("org" "configs/cfg_orgmode.el" t) ("gnus" "configs/cfg_gnus.el" t) ("nnmail" "configs/cfg_gnus.el" t)))) '(ispell-program-name "aspell") '(jabber-account-list (quote (("[email protected]")))) '(jabber-nickname "AVK") '(jabber-password nil) '(jabber-server "halogen-dg.com") '(jabber-username "alex") '(remember-data-file "~/Plans/remember.org") '(safe-local-variable-values (quote ((dtml-top-element . "body")))) '(save-place t nil (saveplace)) '(scroll-bar-mode (quote right)) '(semantic-idle-scheduler-idle-time 432000) '(show-paren-mode t) '(svn-status-hide-unmodified t) '(tool-bar-mode nil nil (tool-bar)) '(transient-mark-mode t) '(truncate-lines f) '(woman-use-own-frame nil)) ; ?? ????? ??????? y ??? n? (fset 'yes-or-no-p 'y-or-n-p) (custom-set-faces ;; custom-set-faces was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won't work right. '(compilation-error ((t (:foreground "tomato" :weight bold)))) '(cursor ((t (:background "red1")))) '(custom-variable-tag ((((class color) (background dark)) (:inherit variable-pitch :foreground "DarkOrange" :weight bold)))) '(hl-line ((t (:background "grey24")))) '(isearch ((t (:background "orange" :foreground "black")))) '(message-cited-text ((((class color) (background dark)) (:foreground "SandyBrown")))) '(message-header-name ((((class color) (background dark)) (:foreground "DarkGrey")))) '(message-header-other ((((class color) (background dark)) (:foreground "LightPink2")))) '(message-header-subject ((((class color) (background dark)) (:foreground "yellow2")))) '(message-separator ((((class color) (background dark)) (:foreground "thistle")))) '(region ((t (:background "brown")))) '(tooltip ((((class color)) (:inherit variable-pitch :background "IndianRed1" :foreground "black"))))) The above is a python emacs configure file. Where should I put it to use it? And, are there any other changes I need to make?

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  • Setting up ProxyPass for a Virtualmin virtual server

    - by Andy Ibanez
    I am trying to set up my web server so that I can server multiple Ghost.org blogs. I am stuck in one crucial step. To be honest, my knowledge in servers is not so big, so I request your help to do this. Basically, a tutorial I'm reading suggests I set up a VirtualHost in this way: NameVirtualHost *:80 <VirtualHost *:80> ServerName your-url.com ServerAlias www.your-url.com ProxyRequests off ProxyPass / http://127.0.0.1:2368/ ProxyPassReverse / http:/127.0.0.1:2368/ </VirtualHost> So I have gone to the Virtual site on Virtualmin to try to add everything as is. Services Configure Website Edit Directives The problem is, the previous page (Services Configure website) says I can't edit the port: This Apache virtual host belongs to the Virtualmin server linguist.andyibanez.com, so the address, port, base directory and hostname cannot be changed here. And whenever I try to add the ProxyRequests off (the other two can be added fine) directive in Edit Directives manually, I'm simply told that the directive can't be there. So what is the right way to "add" the last three directives in the VirtualHost above to my sub server? Maybe I'm missing a menu item that will help me with this? I request your help as I have looked for a while, Google keeps thinking I want to serve Webmin via Apache when I google "Set up Virtualmin proxypass", and I have no clue what to do.

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  • vagrant up command very slow on OS X Lion

    - by Andy Hume
    When I run vagrant up to provision a new VM on Lion it takes an extremely long time, during which the entire Mac is very laggy and unresponsive. The output is as follows, the key point being the "notice: Finished catalog run in 754.28 seconds" > vagrant up [default] Importing base box 'lucid64'... [default] The guest additions on this VM do not match the install version of VirtualBox! This may cause things such as forwarded ports, shared folders, and more to not work properly. If any of those things fail on this machine, please update the guest additions and repackage the box. Guest Additions Version: 4.1.0 VirtualBox Version: 4.1.6 [default] Matching MAC address for NAT networking... [default] Clearing any previously set forwarded ports... [default] Forwarding ports... [default] -- ssh: 22 => 2222 (adapter 1) [default] -- web: 80 => 4567 (adapter 1) [default] Creating shared folders metadata... [default] Running any VM customizations... [default] Booting VM... [default] Waiting for VM to boot. This can take a few minutes. [default] VM booted and ready for use! [default] Mounting shared folders... [default] -- v-root: /vagrant [default] -- v-data: /var/www [default] -- manifests: /tmp/vagrant-puppet/manifests [default] Running provisioner: Vagrant::Provisioners::Puppet... [default] Running Puppet with lucid64.pp... [default] stdin: is not a tty [default] notice: /Stage[main]/Lucid64/Exec[apt-update]/returns: executed successfully [default] [default] notice: /Stage[main]/Lucid64/Package[apache2]/ensure: ensure changed 'purged' to 'present' [default] [default] notice: /Stage[main]/Lucid64/File[/etc/motd]/ensure: defined content as '{md5}a25e31ba9b8489da9cd5751c447a1741' [default] [default] notice: Finished catalog run in 754.28 seconds [default] [default] err: /File[/var/lib/puppet/rrd]/ensure: change from absent to directory failed: Could not find group puppet [default] [default] err: Could not send report: Got 1 failure(s) while initializing: change from absent to directory failed: Could not find group puppet [default] [default] Running provisioner: Vagrant::Provisioners::Puppet... [default] Running Puppet with lucid64.pp... [default] stdin: is not a tty [default] notice: /Stage[main]/Lucid64/Exec[apt-update]/returns: executed successfully [default] [default] notice: Finished catalog run in 2.05 seconds [default] [default] err: /File[/var/lib/puppet/rrd]: Could not evaluate: Could not find group puppet [default] [default] err: Could not send report: Got 1 failure(s) while initializing: Could not evaluate: Could not find group puppet [default] [default] Running provisioner: Vagrant::Provisioners::Puppet... [default] Running Puppet with lucid64.pp... [default] stdin: is not a tty [default] notice: /Stage[main]/Lucid64/Exec[apt-update]/returns: executed successfully [default] [default] notice: Finished catalog run in 1.36 seconds [default] [default] err: /File[/var/lib/puppet/rrd]: Could not evaluate: Could not find group puppet [default] [default] err: Could not send report: Got 1 failure(s) while initializing: Could not evaluate: Could not find group puppet [default] >

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