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  • ANTS CLR and Memory Profiler In Depth Review (Part 1 of 2 &ndash; CLR Profiler)

    - by ToStringTheory
    One of the things that people might not know about me, is my obsession to make my code as efficient as possible.  Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind…  In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve.  One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well.  In this review, I am going to cover some of the features of the ANTS profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program.  I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction The ANTS Profiler pack provided by Red Gate was something that I had not heard of before receiving an email regarding an offer to review it for a license.  Since I look to make my code efficient, it was a no brainer for me to try it out!  One thing that I have to say took me by surprise is that upon downloading the program and installing it you fill out a form for your usual contact information.  Sure enough within 2 hours, I received an email from a sales representative at Red Gate asking if she could help me to achieve the most out of my trial time so it wouldn’t go to waste.  After replying to her and explaining that I was looking to review its feature set, she put me in contact with someone that setup a demo session to give me a quick rundown of its features via an online meeting.  After having dealt with a massive ordeal with one of my utility companies and their complete lack of customer service, Red Gates friendly and helpful representatives were a breath of fresh air, and something I was thankful for. ANTS CLR Profiler The ANTS CLR profiler is the thing I want to focus on the most in this post, so I am going to dive right in now. Install was simple and took no time at all.  It installed both the profiler for the CLR and Memory, but also visual studio extensions to facilitate the usage of the profilers (click any images for full size images): The Visual Studio menu options (under ANTS menu) Starting the CLR Performance Profiler from the start menu yields this window If you follow the instructions after launching the program from the start menu (Click File > New Profiling Session to start a new project), you are given a dialog with plenty of options for profiling: The New Session dialog.  Lots of options.  One thing I noticed is that the buttons in the lower right were half-covered by the panel of the application.  If I had to guess, I would imagine that this is caused by my DPI settings being set to 125%.  This is a problem I have seen in other applications as well that don’t scale well to different dpi scales. The profiler options give you the ability to profile: .NET Executable ASP.NET web application (hosted in IIS) ASP.NET web application (hosted in IIS express) ASP.NET web application (hosted in Cassini Web Development Server) SharePoint web application (hosted in IIS) Silverlight 4+ application Windows Service COM+ server XBAP (local XAML browser application) Attach to an already running .NET 4 process Choosing each option provides a varying set of other variables/options that one can set including options such as application arguments, operating path, record I/O performance performance counters to record (43 counters in all!), etc…  All in all, they give you the ability to profile many different .Net project types, and make it simple to do so.  In most cases of my using this application, I would be using the built in Visual Studio extensions, as they automatically start a new profiling project in ANTS with the options setup, and start your program, however RedGate has made it easy enough to profile outside of Visual Studio as well. On the flip side of this, as someone who lives most of their work life in Visual Studio, one thing I do wish is that instead of opening an entirely separate application/gui to perform profiling after launching, that instead they would provide a Visual Studio panel with the information, and integrate more of the profiling project information into Visual Studio.  So, now that we have an idea of what options that the profiler gives us, its time to test its abilities and features. Horrendous Example Code – Prime Number Generator One of my interests besides development, is Physics and Math – what I went to college for.  I have especially always been interested in prime numbers, as they are something of a mystery…  So, I decided that I would go ahead and to test the abilities of the profiler, I would write a small program, website, and library to generate prime numbers in the quantity that you ask for.  I am going to start off with some terrible code, and show how I would see the profiler being used as a development tool. First off, the IPrimes interface (all code is downloadable at the end of the post): interface IPrimes { IEnumerable<int> GetPrimes(int retrieve); } Simple enough, right?  Anything that implements the interface will (hopefully) provide an IEnumerable of int, with the quantity specified in the parameter argument.  Next, I am going to implement this interface in the most basic way: public class DumbPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _analyzing = 4; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; //start dividing at 2 //divide until number is reached, or determined not prime for (int i = 2; i < _analyzing && isPrime; i++) { //if (i) goes into _analyzing without a remainder, //_analyzing is NOT prime if (_analyzing % i == 0) isPrime = false; } //if it is prime, add to found list if (isPrime) _foundPrimes.Add(_analyzing); //increment number to analyze next _analyzing++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } This is the simplest way to get primes in my opinion.  Checking each number by the straight definition of a prime – is it divisible by anything besides 1 and itself. I have included this code in a base class library for my solution, as I am going to use it to demonstrate a couple of features of ANTS.  This class library is consumed by a simple non-MVVM WPF application, and a simple MVC4 website.  I will not post the WPF code here inline, as it is simply an ObservableCollection<int>, a label, two textbox’s, and a button. Starting a new Profiling Session So, in Visual Studio, I have just completed my first stint developing the GUI and DumbPrimes IPrimes class, so now I want to check my codes efficiency by profiling it.  All I have to do is build the solution (surprised initiating a profiling session doesn’t do this, but I suppose I can understand it), and then click the ANTS menu, followed by Profile Performance.  I am then greeted by the profiler starting up and already monitoring my program live: You are provided with a realtime graph at the top, and a pane at the bottom giving you information on how to proceed.  I am going to start by asking my program to show me the first 15000 primes: After the program finally began responding again (I did all the work on the main UI thread – how bad!), I stopped the profiler, which did kill the process of my program too.  One important thing to note, is that the profiler by default wants to give you a lot of detail about the operation – line hit counts, time per line, percent time per line, etc…  The important thing to remember is that this itself takes a lot of time.  When running my program without the profiler attached, it can generate the 15000 primes in 5.18 seconds, compared to 74.5 seconds – almost a 1500 percent increase.  While this may seem like a lot, remember that there is a trade off.  It may be WAY more inefficient, however, I am able to drill down and make improvements to specific problem areas, and then decrease execution time all around. Analyzing the Profiling Session After clicking ‘Stop Profiling’, the process running my application stopped, and the entire execution time was automatically selected by ANTS, and the results shown below: Now there are a number of interesting things going on here, I am going to cover each in a section of its own: Real Time Performance Counter Bar (top of screen) At the top of the screen, is the real time performance bar.  As your application is running, this will constantly update with the currently selected performance counters status.  A couple of cool things to note are the fact that you can drag a selection around specific time periods to drill down the detail views in the lower 2 panels to information pertaining to only that period. After selecting a time period, you can bookmark a section and name it, so that it is easy to find later, or after reloaded at a later time.  You can also zoom in, out, or fit the graph to the space provided – useful for drilling down. It may be hard to see, but at the top of the processor time graph below the time ticks, but above the red usage graph, there is a green bar. This bar shows at what times a method that is selected in the ‘Call tree’ panel is called. Very cool to be able to click on a method and see at what times it made an impact. As I said before, ANTS provides 43 different performance counters you can hook into.  Click the arrow next to the Performance tab at the top will allow you to change between different counters if you have them selected: Method Call Tree, ADO.Net Database Calls, File IO – Detail Panel Red Gate really hit the mark here I think. When you select a section of the run with the graph, the call tree populates to fill a hierarchical tree of method calls, with information regarding each of the methods.   By default, methods are hidden where the source is not provided (framework type code), however, Red Gate has integrated Reflector into ANTS, so even if you don’t have source for something, you can select a method and get the source if you want.  Methods are also hidden where the impact is seen as insignificant – methods that are only executed for 1% of the time of the overall calling methods time; in other words, working on making them better is not where your efforts should be focused. – Smart! Source Panel – Detail Panel The source panel is where you can see line level information on your code, showing the code for the currently selected method from the Method Call Tree.  If the code is not available, Reflector takes care of it and shows the code anyways! As you can notice, there does seem to be a problem with how ANTS determines what line is the actual line that a call is completed on.  I have suspicions that this may be due to some of the inline code optimizations that the CLR applies upon compilation of the assembly.  In a method with comments, the problem is much more severe: As you can see here, apparently the most offending code in my base library was a comment – *gasp*!  Removing the comments does help quite a bit, however I hope that Red Gate works on their counter algorithm soon to improve the logic on positioning for statistics: I did a small test just to demonstrate the lines are correct without comments. For me, it isn’t a deal breaker, as I can usually determine the correct placements by looking at the application code in the region and determining what makes sense, but it is something that would probably build up some irritation with time. Feature – Suggest Method for Optimization A neat feature to really help those in need of a pointer, is the menu option under tools to automatically suggest methods to optimize/improve: Nice feature – clicking it filters the call tree and stars methods that it thinks are good candidates for optimization.  I do wish that they would have made it more visible for those of use who aren’t great on sight: Process Integration I do think that this could have a place in my process.  After experimenting with the profiler, I do think it would be a great benefit to do some development, testing, and then after all the bugs are worked out, use the profiler to check on things to make sure nothing seems like it is hogging more than its fair share.  For example, with this program, I would have developed it, ran it, tested it – it works, but slowly. After looking at the profiler, and seeing the massive amount of time spent in 1 method, I might go ahead and try to re-implement IPrimes (I actually would probably rewrite the offending code, but so that I can distribute both sets of code easily, I’m just going to make another implementation of IPrimes).  Using two pieces of knowledge about prime numbers can make this method MUCH more efficient – prime numbers fall into two buckets 6k+/-1 , and a number is prime if it is not divisible by any other primes before it: public class SmartPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _k = 1; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; int potentialPrime; //analyze 6k-1 //assign the value to potential potentialPrime = 6 * _k - 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); if (_foundPrimes.Count() == retrieve) break; //analyze 6k+1 //assign the value to potential potentialPrime = 6 * _k + 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); //increment k to analyze next _k++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } Now there are definitely more things I can do to help make this more efficient, but for the scope of this example, I think this is fine (but still hideous)! Profiling this now yields a happy surprise 27 seconds to generate the 15000 primes with the profiler attached, and only 1.43 seconds without.  One important thing I wanted to call out though was the performance graph now: Notice anything odd?  The %Processor time is above 100%.  This is because there is now more than 1 core in the operation.  A better label for the chart in my mind would have been %Core time, but to each their own. Another odd thing I noticed was that the profiler seemed to be spot on this time in my DumbPrimes class with line details in source, even with comments..  Odd. Profiling Web Applications The last thing that I wanted to cover, that means a lot to me as a web developer, is the great amount of work that Red Gate put into the profiler when profiling web applications.  In my solution, I have a simple MVC4 application setup with 1 page, a single input form, that will output prime values as my WPF app did.  Launching the profiler from Visual Studio as before, nothing is really different in the profiler window, however I did receive a UAC prompt for a Red Gate helper app to integrate with the web server without notification. After requesting 500, 1000, 2000, and 5000 primes, and looking at the profiler session, things are slightly different from before: As you can see, there are 4 spikes of activity in the processor time graph, but there is also something new in the call tree: That’s right – ANTS will actually group method calls by get/post operations, so it is easier to find out what action/page is giving the largest problems…  Pretty cool in my mind! Overview Overall, I think that Red Gate ANTS CLR Profiler has a lot to offer, however I think it also has a long ways to go.  3 Biggest Pros: Ability to easily drill down from time graph, to method calls, to source code Wide variety of counters to choose from when profiling your application Excellent integration/grouping of methods being called from web applications by request – BRILLIANT! 3 Biggest Cons: Issue regarding line details in source view Nit pick – Processor time vs. Core time Nit pick – Lack of full integration with Visual Studio Ratings Ease of Use (7/10) – I marked down here because of the problems with the line level details and the extra work that that entails, and the lack of better integration with Visual Studio. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do.  Especially with its large variety of performance counters, a definite plus! Features (9/10) – Besides the real time performance monitoring, and the drill downs that I’ve shown here, ANTS also has great integration with ADO.Net, with the ability to show database queries run by your application in the profiler.  This, with the line level details, the web request grouping, reflector integration, and various options to customize your profiling session I think create a great set of features! Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good.  their people are friendly, helpful, and happy! UI / UX (8/10) – The interface is very easy to get around, and all of the options are easy to find.  With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (8/10) – Overall, I am happy with the Performance Profiler and its features, as well as with the service I received when working with the Red Gate personnel.  I WOULD recommend you trying the application and seeing if it would fit into your process, BUT, remember there are still some kinks in it to hopefully be worked out. My next post will definitely be shorter (hopefully), but thank you for reading up to here, or skipping ahead!  Please, if you do try the product, drop me a message and let me know what you think!  I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

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  • ANTS Memory Profiler 7.0 Review

    - by Michael B. McLaughlin
    (This is my first review as a part of the GeeksWithBlogs.net Influencers program. It’s a program in which I (and the others who have been selected for it) get the opportunity to check out new products and services and write reviews about them. We don’t get paid for this, but we do generally get to keep a copy of the software or retain an account for some period of time on the service that we review. In this case I received a copy of Red Gate Software’s ANTS Memory Profiler 7.0, which was released in January. I don’t have any upgrade rights nor is my review guided, restrained, influenced, or otherwise controlled by Red Gate or anyone else. But I do get to keep the software license. I will always be clear about what I received whenever I do a review – I leave it up to you to decide whether you believe I can be objective. I believe I can be. If I used something and really didn’t like it, keeping a copy of it wouldn’t be worth anything to me. In that case though, I would simply uninstall/deactivate/whatever the software or service and tell the company what I didn’t like about it so they could (hopefully) make it better in the future. I don’t think it’d be polite to write up a terrible review, nor do I think it would be a particularly good use of my time. There are people who get paid for a living to review things, so I leave it to them to tell you what they think is bad and why. I’ll only spend my time telling you about things I think are good.) Overview of Common .NET Memory Problems When coming to land of managed memory from the wilds of unmanaged code, it’s easy to say to one’s self, “Wow! Now I never have to worry about memory problems again!” But this simply isn’t true. Managed code environments, such as .NET, make many, many things easier. You will never have to worry about memory corruption due to a bad pointer, for example (unless you’re working with unsafe code, of course). But managed code has its own set of memory concerns. For example, failing to unsubscribe from events when you are done with them leaves the publisher of an event with a reference to the subscriber. If you eliminate all your own references to the subscriber, then that memory is effectively lost since the GC won’t delete it because of the publishing object’s reference. When the publishing object itself becomes subject to garbage collection then you’ll get that memory back finally, but that could take a very long time depending of the life of the publisher. Another common source of resource leaks is failing to properly release unmanaged resources. When writing a class that contains members that hold unmanaged resources (e.g. any of the Stream-derived classes, IsolatedStorageFile, most classes ending in “Reader” or “Writer”), you should always implement IDisposable, making sure to use a properly written Dispose method. And when you are using an instance of a class that implements IDisposable, you should always make sure to use a 'using' statement in order to ensure that the object’s unmanaged resources are disposed of properly. (A ‘using’ statement is a nicer, cleaner looking, and easier to use version of a try-finally block. The compiler actually translates it as though it were a try-finally block. Note that Code Analysis warning 2202 (CA2202) will often be triggered by nested using blocks. A properly written dispose method ensures that it only runs once such that calling dispose multiple times should not be a problem. Nonetheless, CA2202 exists and if you want to avoid triggering it then you should write your code such that only the innermost IDisposable object uses a ‘using’ statement, with any outer code making use of appropriate try-finally blocks instead). Then, of course, there are situations where you are operating in a memory-constrained environment or else you want to limit or even eliminate allocations within a certain part of your program (e.g. within the main game loop of an XNA game) in order to avoid having the GC run. On the Xbox 360 and Windows Phone 7, for example, for every 1 MB of heap allocations you make, the GC runs; the added time of a GC collection can cause a game to drop frames or run slowly thereby making it look bad. Eliminating allocations (or else minimizing them and calling an explicit Collect at an appropriate time) is a common way of avoiding this (the other way is to simplify your heap so that the GC’s latency is low enough not to cause performance issues). ANTS Memory Profiler 7.0 When the opportunity to review Red Gate’s recently released ANTS Memory Profiler 7.0 arose, I jumped at it. In order to review it, I was given a free copy (which does not include upgrade rights for future versions) which I am allowed to keep. For those of you who are familiar with ANTS Memory Profiler, you can find a list of new features and enhancements here. If you are an experienced .NET developer who is familiar with .NET memory management issues, ANTS Memory Profiler is great. More importantly still, if you are new to .NET development or you have no experience or limited experience with memory profiling, ANTS Memory Profiler is awesome. From the very beginning, it guides you through the process of memory profiling. If you’re experienced and just want dive in however, it doesn’t get in your way. The help items GAHSFLASHDAJLDJA are well designed and located right next to the UI controls so that they are easy to find without being intrusive. When you first launch it, it presents you with a “Getting Started” screen that contains links to “Memory profiling video tutorials”, “Strategies for memory profiling”, and the “ANTS Memory Profiler forum”. I’m normally the kind of person who looks at a screen like that only to find the “Don’t show this again” checkbox. Since I was doing a review, though, I decided I should examine them. I was pleasantly surprised. The overview video clocks in at three minutes and fifty seconds. It begins by showing you how to get started profiling an application. It explains that profiling is done by taking memory snapshots periodically while your program is running and then comparing them. ANTS Memory Profiler (I’m just going to call it “ANTS MP” from here) analyzes these snapshots in the background while your application is running. It briefly mentions a new feature in Version 7, a new API that give you the ability to trigger snapshots from within your application’s source code (more about this below). You can also, and this is the more common way you would do it, take a memory snapshot at any time from within the ANTS MP window by clicking the “Take Memory Snapshot” button in the upper right corner. The overview video goes on to demonstrate a basic profiling session on an application that pulls information from a database and displays it. It shows how to switch which snapshots you are comparing, explains the different sections of the Summary view and what they are showing, and proceeds to show you how to investigate memory problems using the “Instance Categorizer” to track the path from an object (or set of objects) to the GC’s root in order to find what things along the path are holding a reference to it/them. For a set of objects, you can then click on it and get the “Instance List” view. This displays all of the individual objects (including their individual sizes, values, etc.) of that type which share the same path to the GC root. You can then click on one of the objects to generate an “Instance Retention Graph” view. This lets you track directly up to see the reference chain for that individual object. In the overview video, it turned out that there was an event handler which was holding on to a reference, thereby keeping a large number of strings that should have been freed in memory. Lastly the video shows the “Class List” view, which lets you dig in deeply to find problems that might not have been clear when following the previous workflow. Once you have at least one memory snapshot you can begin analyzing. The main interface is in the “Analysis” tab. You can also switch to the “Session Overview” tab, which gives you several bar charts highlighting basic memory data about the snapshots you’ve taken. If you hover over the individual bars (and the individual colors in bars that have more than one), you will see a detailed text description of what the bar is representing visually. The Session Overview is good for a quick summary of memory usage and information about the different heaps. You are going to spend most of your time in the Analysis tab, but it’s good to remember that the Session Overview is there to give you some quick feedback on basic memory usage stats. As described above in the summary of the overview video, there is a certain natural workflow to the Analysis tab. You’ll spin up your application and take some snapshots at various times such as before and after clicking a button to open a window or before and after closing a window. Taking these snapshots lets you examine what is happening with memory. You would normally expect that a lot of memory would be freed up when closing a window or exiting a document. By taking snapshots before and after performing an action like that you can see whether or not the memory is really being freed. If you already know an area that’s giving you trouble, you can run your application just like normal until just before getting to that part and then you can take a few strategic snapshots that should help you pin down the problem. Something the overview didn’t go into is how to use the “Filters” section at the bottom of ANTS MP together with the Class List view in order to narrow things down. The video tutorials page has a nice 3 minute intro video called “How to use the filters”. It’s a nice introduction and covers some of the basics. I’m going to cover a bit more because I think they’re a really neat, really helpful feature. Large programs can bring up thousands of classes. Even simple programs can instantiate far more classes than you might realize. In a basic .NET 4 WPF application for example (and when I say basic, I mean just MainWindow.xaml with a button added to it), the unfiltered Class List view will have in excess of 1000 classes (my simple test app had anywhere from 1066 to 1148 classes depending on which snapshot I was using as the “Current” snapshot). This is amazing in some ways as it shows you how in stark detail just how immensely powerful the WPF framework is. But hunting through 1100 classes isn’t productive, no matter how cool it is that there are that many classes instantiated and doing all sorts of awesome things. Let’s say you wanted to examine just the classes your application contains source code for (in my simple example, that would be the MainWindow and App). Under “Basic Filters”, click on “Classes with source” under “Show only…”. Voilà. Down from 1070 classes in the snapshot I was using as “Current” to 2 classes. If you then click on a class’s name, it will show you (to the right of the class name) two little icon buttons. Hover over them and you will see that you can click one to view the Instance Categorizer for the class and another to view the Instance List for the class. You can also show classes based on which heap they live on. If you chose both a Baseline snapshot and a Current snapshot then you can use the “Comparing snapshots” filters to show only: “New objects”; “Surviving objects”; “Survivors in growing classes”; or “Zombie objects” (if you aren’t sure what one of these means, you can click the helpful “?” in a green circle icon to bring up a popup that explains them and provides context). Remember that your selection(s) under the “Show only…” heading will still apply, so you should update those selections to make sure you are seeing the view you want. There are also links under the “What is my memory problem?” heading that can help you diagnose the problems you are seeing including one for “I don’t know which kind I have” for situations where you know generally that your application has some problems but aren’t sure what the behavior you have been seeing (OutOfMemoryExceptions, continually growing memory usage, larger memory use than expected at certain points in the program). The Basic Filters are not the only filters there are. “Filter by Object Type” gives you the ability to filter by: “Objects that are disposable”; “Objects that are/are not disposed”; “Objects that are/are not GC roots” (GC roots are things like static variables); and “Objects that implement _______”. “Objects that implement” is particularly neat. Once you check the box, you can then add one or more classes and interfaces that an object must implement in order to survive the filtering. Lastly there is “Filter by Reference”, which gives you the option to pare down the list based on whether an object is “Kept in memory exclusively by” a particular item, a class/interface, or a namespace; whether an object is “Referenced by” one or more of those choices; and whether an object is “Never referenced by” one or more of those choices. Remember that filtering is cumulative, so anything you had set in one of the filter sections still remains in effect unless and until you go back and change it. There’s quite a bit more to ANTS MP – it’s a very full featured product – but I think I touched on all of the most significant pieces. You can use it to debug: a .NET executable; an ASP.NET web application (running on IIS); an ASP.NET web application (running on Visual Studio’s built-in web development server); a Silverlight 4 browser application; a Windows service; a COM+ server; and even something called an XBAP (local XAML browser application). You can also attach to a .NET 4 process to profile an application that’s already running. The startup screen also has a large number of “Charting Options” that let you adjust which statistics ANTS MP should collect. The default selection is a good, minimal set. It’s worth your time to browse through the charting options to examine other statistics that may also help you diagnose a particular problem. The more statistics ANTS MP collects, the longer it will take to collect statistics. So just turning everything on is probably a bad idea. But the option to selectively add in additional performance counters from the extensive list could be a very helpful thing for your memory profiling as it lets you see additional data that might provide clues about a particular problem that has been bothering you. ANTS MP integrates very nicely with all versions of Visual Studio that support plugins (i.e. all of the non-Express versions). Just note that if you choose “Profile Memory” from the “ANTS” menu that it will launch profiling for whichever project you have set as the Startup project. One quick tip from my experience so far using ANTS MP: if you want to properly understand your memory usage in an application you’ve written, first create an “empty” version of the type of project you are going to profile (a WPF application, an XNA game, etc.) and do a quick profiling session on that so that you know the baseline memory usage of the framework itself. By “empty” I mean just create a new project of that type in Visual Studio then compile it and run it with profiling – don’t do anything special or add in anything (except perhaps for any external libraries you’re planning to use). The first thing I tried ANTS MP out on was a demo XNA project of an editor that I’ve been working on for quite some time that involves a custom extension to XNA’s content pipeline. The first time I ran it and saw the unmanaged memory usage I was convinced I had some horrible bug that was creating extra copies of texture data (the demo project didn’t have a lot of texture data so when I saw a lot of unmanaged memory I instantly figured I was doing something wrong). Then I thought to run an empty project through and when I saw that the amount of unmanaged memory was virtually identical, it dawned on me that the CLR itself sits in unmanaged memory and that (thankfully) there was nothing wrong with my code! Quite a relief. Earlier, when discussing the overview video, I mentioned the API that lets you take snapshots from within your application. I gave it a quick trial and it’s very easy to integrate and make use of and is a really nice addition (especially for projects where you want to know what, if any, allocations there are in a specific, complicated section of code). The only concern I had was that if I hadn’t watched the overview video I might never have known it existed. Even then it took me five minutes of hunting around Red Gate’s website before I found the “Taking snapshots from your code" article that explains what DLL you need to add as a reference and what method of what class you should call in order to take an automatic snapshot (including the helpful warning to wrap it in a try-catch block since, under certain circumstances, it can raise an exception, such as trying to call it more than 5 times in 30 seconds. The difficulty in discovering and then finding information about the automatic snapshots API was one thing I thought could use improvement. Another thing I think would make it even better would be local copies of the webpages it links to. Although I’m generally always connected to the internet, I imagine there are more than a few developers who aren’t or who are behind very restrictive firewalls. For them (and for me, too, if my internet connection happens to be down), it would be nice to have those documents installed locally or to have the option to download an additional “documentation” package that would add local copies. Another thing that I wish could be easier to manage is the Filters area. Finding and setting individual filters is very easy as is understanding what those filter do. And breaking it up into three sections (basic, by object, and by reference) makes sense. But I could easily see myself running a long profiling session and forgetting that I had set some filter a long while earlier in a different filter section and then spending quite a bit of time trying to figure out why some problem that was clearly visible in the data wasn’t showing up in, e.g. the instance list before remembering to check all the filters for that one setting that was only culling a few things from view. Some sort of indicator icon next to the filter section names that appears you have at least one filter set in that area would be a nice visual clue to remind me that “oh yeah, I told it to only show objects on the Gen 2 heap! That’s why I’m not seeing those instances of the SuperMagic class!” Something that would be nice (but that Red Gate cannot really do anything about) would be if this could be used in Windows Phone 7 development. If Microsoft and Red Gate could work together to make this happen (even if just on the WP7 emulator), that would be amazing. Especially given the memory constraints that apps and games running on mobile devices need to work within, a good memory profiler would be a phenomenally helpful tool. If anyone at Microsoft reads this, it’d be really great if you could make something like that happen. Perhaps even a (subsidized) custom version just for WP7 development. (For XNA games, of course, you can create a Windows version of the game and use ANTS MP on the Windows version in order to get a better picture of your memory situation. For Silverlight on WP7, though, there’s quite a bit of educated guess work and WeakReference creation followed by forced collections in order to find the source of a memory problem.) The only other thing I found myself wanting was a “Back” button. Between my Windows Phone 7, Zune, and other things, I’ve grown very used to having a “back stack” that lets me just navigate back to where I came from. The ANTS MP interface is surprisingly easy to use given how much it lets you do, and once you start using it for any amount of time, you learn all of the different areas such that you know where to go. And it does remember the state of the areas you were previously in, of course. So if you go to, e.g., the Instance Retention Graph from the Class List and then return back to the Class List, it will remember which class you had selected and all that other state information. Still, a “Back” button would be a welcome addition to a future release. Bottom Line ANTS Memory Profiler is not an inexpensive tool. But my time is valuable. I can easily see ANTS MP saving me enough time tracking down memory problems to justify it on a cost basis. More importantly to me, knowing what is happening memory-wise in my programs and having the confidence that my code doesn’t have any hidden time bombs in it that will cause it to OOM if I leave it running for longer than I do when I spin it up real quickly for debugging or just to see how a new feature looks and feels is a good feeling. It’s a feeling that I like having and want to continue to have. I got the current version for free in order to review it. Having done so, I’ve now added it to my must-have tools and will gladly lay out the money for the next version when it comes out. It has a 14 day free trial, so if you aren’t sure if it’s right for you or if you think it seems interesting but aren’t really sure if it’s worth shelling out the money for it, give it a try.

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  • Cisco SR520w FE - WAN Port Stops Working

    - by Mike Hanley
    I have setup a Cisco SR520W and everything appears to be working. After about 1-2 days, it looks like the WAN port stops forwarding traffic to the Internet gateway IP of the device. If I unplug and then plug in the network cable connecting the WAN port of the SR520W to my Comcast Cable Modem, traffic startings flowing again. Also, if I restart the SR520W, the traffic will flow again. Any ideas? Here is the running config: Current configuration : 10559 bytes ! version 12.4 no service pad no service timestamps debug uptime service timestamps log datetime msec no service password-encryption ! hostname hostname.mydomain.com ! boot-start-marker boot-end-marker ! logging message-counter syslog no logging rate-limit enable secret 5 <removed> ! aaa new-model ! ! aaa authentication login default local aaa authorization exec default local ! ! aaa session-id common clock timezone PST -8 clock summer-time PDT recurring ! crypto pki trustpoint TP-self-signed-334750407 enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-334750407 revocation-check none rsakeypair TP-self-signed-334750407 ! ! crypto pki certificate chain TP-self-signed-334750407 certificate self-signed 01 <removed> quit dot11 syslog ! dot11 ssid <removed> vlan 75 authentication open authentication key-management wpa guest-mode wpa-psk ascii 0 <removed> ! ip source-route ! ! ip dhcp excluded-address 172.16.0.1 172.16.0.10 ! ip dhcp pool inside import all network 172.16.0.0 255.240.0.0 default-router 172.16.0.1 dns-server 10.0.0.15 10.0.0.12 domain-name mydomain.com ! ! ip cef ip domain name mydomain.com ip name-server 68.87.76.178 ip name-server 66.240.48.9 ip port-map user-ezvpn-remote port udp 10000 ip ips notify SDEE ip ips name sdm_ips_rule ! ip ips signature-category category all retired true category ios_ips basic retired false ! ip inspect log drop-pkt no ipv6 cef ! multilink bundle-name authenticated parameter-map type inspect z1-z2-pmap audit-trail on password encryption aes ! ! username admin privilege 15 secret 5 <removed> ! crypto key pubkey-chain rsa named-key realm-cisco.pub key-string <removed> quit ! ! ! ! ! ! crypto ipsec client ezvpn EZVPN_REMOTE_CONNECTION_1 connect auto group EZVPN_GROUP_1 key <removed> mode client peer 64.1.208.90 virtual-interface 1 username admin password <removed> xauth userid mode local ! ! archive log config logging enable logging size 600 hidekeys ! ! ! class-map type inspect match-any SDM_AH match access-group name SDM_AH class-map type inspect match-any SDM-Voice-permit match protocol sip class-map type inspect match-any SDM_ESP match access-group name SDM_ESP class-map type inspect match-any SDM_EASY_VPN_REMOTE_TRAFFIC match protocol isakmp match protocol ipsec-msft match class-map SDM_AH match class-map SDM_ESP match protocol user-ezvpn-remote class-map type inspect match-all SDM_EASY_VPN_REMOTE_PT match class-map SDM_EASY_VPN_REMOTE_TRAFFIC match access-group 101 class-map type inspect match-any Easy_VPN_Remote_VT match access-group 102 class-map type inspect match-any sdm-cls-icmp-access match protocol icmp match protocol tcp match protocol udp class-map type inspect match-any sdm-cls-insp-traffic match protocol cuseeme match protocol dns match protocol ftp match protocol h323 match protocol https match protocol icmp match protocol imap match protocol pop3 match protocol netshow match protocol shell match protocol realmedia match protocol rtsp match protocol smtp extended match protocol sql-net match protocol streamworks match protocol tftp match protocol vdolive match protocol tcp match protocol udp class-map type inspect match-any L4-inspect-class match protocol icmp class-map type inspect match-all sdm-invalid-src match access-group 100 class-map type inspect match-all dhcp_out_self match access-group name dhcp-resp-permit class-map type inspect match-all dhcp_self_out match access-group name dhcp-req-permit class-map type inspect match-all sdm-protocol-http match protocol http ! ! policy-map type inspect sdm-permit-icmpreply class type inspect dhcp_self_out pass class type inspect sdm-cls-icmp-access inspect class class-default pass policy-map type inspect sdm-permit_VT class type inspect Easy_VPN_Remote_VT pass class class-default drop policy-map type inspect sdm-inspect class type inspect SDM-Voice-permit pass class type inspect sdm-cls-insp-traffic inspect class type inspect sdm-invalid-src drop log class type inspect sdm-protocol-http inspect z1-z2-pmap class class-default pass policy-map type inspect sdm-inspect-voip-in class type inspect SDM-Voice-permit pass class class-default drop policy-map type inspect sdm-permit class type inspect SDM_EASY_VPN_REMOTE_PT pass class type inspect dhcp_out_self pass class class-default drop ! zone security ezvpn-zone zone security out-zone zone security in-zone zone-pair security sdm-zp-in-ezvpn1 source in-zone destination ezvpn-zone service-policy type inspect sdm-permit_VT zone-pair security sdm-zp-out-ezpn1 source out-zone destination ezvpn-zone service-policy type inspect sdm-permit_VT zone-pair security sdm-zp-ezvpn-out1 source ezvpn-zone destination out-zone service-policy type inspect sdm-permit_VT zone-pair security sdm-zp-self-out source self destination out-zone service-policy type inspect sdm-permit-icmpreply zone-pair security sdm-zp-out-in source out-zone destination in-zone service-policy type inspect sdm-inspect-voip-in zone-pair security sdm-zp-ezvpn-in1 source ezvpn-zone destination in-zone service-policy type inspect sdm-permit_VT zone-pair security sdm-zp-out-self source out-zone destination self service-policy type inspect sdm-permit zone-pair security sdm-zp-in-out source in-zone destination out-zone service-policy type inspect sdm-inspect ! bridge irb ! ! interface FastEthernet0 switchport access vlan 75 ! interface FastEthernet1 switchport access vlan 75 ! interface FastEthernet2 switchport access vlan 75 ! interface FastEthernet3 switchport access vlan 75 ! interface FastEthernet4 description $FW_OUTSIDE$ ip address 75.149.48.76 255.255.255.240 ip nat outside ip ips sdm_ips_rule out ip virtual-reassembly zone-member security out-zone duplex auto speed auto crypto ipsec client ezvpn EZVPN_REMOTE_CONNECTION_1 ! interface Virtual-Template1 type tunnel no ip address ip virtual-reassembly zone-member security ezvpn-zone tunnel mode ipsec ipv4 ! interface Dot11Radio0 no ip address ! encryption vlan 75 mode ciphers aes-ccm ! ssid <removed> ! speed basic-1.0 basic-2.0 basic-5.5 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0 54.0 station-role root ! interface Dot11Radio0.75 encapsulation dot1Q 75 native ip virtual-reassembly bridge-group 75 bridge-group 75 subscriber-loop-control bridge-group 75 spanning-disabled bridge-group 75 block-unknown-source no bridge-group 75 source-learning no bridge-group 75 unicast-flooding ! interface Vlan1 no ip address ip virtual-reassembly bridge-group 1 ! interface Vlan75 no ip address ip virtual-reassembly bridge-group 75 bridge-group 75 spanning-disabled ! interface BVI1 no ip address ip nat inside ip virtual-reassembly ! interface BVI75 description $FW_INSIDE$ ip address 172.16.0.1 255.240.0.0 ip nat inside ip ips sdm_ips_rule in ip virtual-reassembly zone-member security in-zone crypto ipsec client ezvpn EZVPN_REMOTE_CONNECTION_1 inside ! ip forward-protocol nd ip route 0.0.0.0 0.0.0.0 75.149.48.78 2 ! ip http server ip http authentication local ip http secure-server ip http timeout-policy idle 60 life 86400 requests 10000 ip nat inside source list 1 interface FastEthernet4 overload ! ip access-list extended SDM_AH remark SDM_ACL Category=1 permit ahp any any ip access-list extended SDM_ESP remark SDM_ACL Category=1 permit esp any any ip access-list extended dhcp-req-permit remark SDM_ACL Category=1 permit udp any eq bootpc any eq bootps ip access-list extended dhcp-resp-permit remark SDM_ACL Category=1 permit udp any eq bootps any eq bootpc ! access-list 1 remark SDM_ACL Category=2 access-list 1 permit 172.16.0.0 0.15.255.255 access-list 100 remark SDM_ACL Category=128 access-list 100 permit ip host 255.255.255.255 any access-list 100 permit ip 127.0.0.0 0.255.255.255 any access-list 100 permit ip 75.149.48.64 0.0.0.15 any access-list 101 remark SDM_ACL Category=128 access-list 101 permit ip host 64.1.208.90 any access-list 102 remark SDM_ACL Category=1 access-list 102 permit ip any any ! ! ! ! snmp-server community <removed> RO ! control-plane ! bridge 1 protocol ieee bridge 1 route ip bridge 75 route ip banner login ^CSR520 Base Config - MFG 1.0 ^C ! line con 0 no modem enable line aux 0 line vty 0 4 transport input telnet ssh ! scheduler max-task-time 5000 end I also ran some diagnostics when the WAN port stopped working: 1. show interface fa4 FastEthernet4 is up, line protocol is up Hardware is PQUICC_FEC, address is 0026.99c5.b434 (bia 0026.99c5.b434) Description: $FW_OUTSIDE$ Internet address is 75.149.48.76/28 MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, 100BaseTX/FX ARP type: ARPA, ARP Timeout 04:00:00 Last input 01:08:15, output 00:00:00, output hang never Last clearing of "show interface" counters never Input queue: 0/75/23/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 1000 bits/sec, 0 packets/sec 336446 packets input, 455403158 bytes Received 23 broadcasts, 0 runts, 0 giants, 37 throttles 41 input errors, 0 CRC, 0 frame, 0 overrun, 41 ignored 0 watchdog 0 input packets with dribble condition detected 172529 packets output, 23580132 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out 2. show ip route Gateway of last resort is 75.149.48.78 to network 0.0.0.0 C 192.168.75.0/24 is directly connected, BVI75 64.0.0.0/32 is subnetted, 1 subnets S 64.1.208.90 [1/0] via 75.149.48.78 S 192.168.10.0/24 is directly connected, BVI75 75.0.0.0/28 is subnetted, 1 subnets C 75.149.48.64 is directly connected, FastEthernet4 S* 0.0.0.0/0 [2/0] via 75.149.48.78 3. show ip arp Protocol Address Age (min) Hardware Addr Type Interface Internet 75.149.48.65 69 001e.2a39.7b08 ARPA FastEthernet4 Internet 75.149.48.76 - 0026.99c5.b434 ARPA FastEthernet4 Internet 75.149.48.78 93 0022.2d6c.ae36 ARPA FastEthernet4 Internet 192.168.75.1 - 0027.0d58.f5f0 ARPA BVI75 Internet 192.168.75.12 50 7c6d.62c7.8c0a ARPA BVI75 Internet 192.168.75.13 0 001b.6301.1227 ARPA BVI75 4. sh ip cef Prefix Next Hop Interface 0.0.0.0/0 75.149.48.78 FastEthernet4 0.0.0.0/8 drop 0.0.0.0/32 receive 64.1.208.90/32 75.149.48.78 FastEthernet4 75.149.48.64/28 attached FastEthernet4 75.149.48.64/32 receive FastEthernet4 75.149.48.65/32 attached FastEthernet4 75.149.48.76/32 receive FastEthernet4 75.149.48.78/32 attached FastEthernet4 75.149.48.79/32 receive FastEthernet4 127.0.0.0/8 drop 192.168.10.0/24 attached BVI75 192.168.75.0/24 attached BVI75 192.168.75.0/32 receive BVI75 192.168.75.1/32 receive BVI75 192.168.75.12/32 attached BVI75 192.168.75.13/32 attached BVI75 192.168.75.255/32 receive BVI75 224.0.0.0/4 drop 224.0.0.0/24 receive 240.0.0.0/4 drop 255.255.255.255/32 receive Thanks in advance, -Mike

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  • Cisco 891w multiple VLAN configuration

    - by Jessica
    I'm having trouble getting my guest network up. I have VLAN 1 that contains all our network resources (servers, desktops, printers, etc). I have the wireless configured to use VLAN1 but authenticate with wpa2 enterprise. The guest network I just wanted to be open or configured with a simple WPA2 personal password on it's own VLAN2. I've looked at tons of documentation and it should be working but I can't even authenticate on the guest network! I've posted this on cisco's support forum a week ago but no one has really responded. I could really use some help. So if anyone could take a look at the configurations I posted and steer me in the right direction I would be extremely grateful. Thank you! version 15.0 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname ESI ! boot-start-marker boot-end-marker ! logging buffered 51200 warnings ! aaa new-model ! ! aaa authentication login userauthen local aaa authorization network groupauthor local ! ! ! ! ! aaa session-id common ! ! ! clock timezone EST -5 clock summer-time EDT recurring service-module wlan-ap 0 bootimage autonomous ! crypto pki trustpoint TP-self-signed-3369945891 enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-3369945891 revocation-check none rsakeypair TP-self-signed-3369945891 ! ! crypto pki certificate chain TP-self-signed-3369945891 certificate self-signed 01 (cert is here) quit ip source-route ! ! ip dhcp excluded-address 192.168.1.1 ip dhcp excluded-address 192.168.1.5 ip dhcp excluded-address 192.168.1.2 ip dhcp excluded-address 192.168.1.200 192.168.1.210 ip dhcp excluded-address 192.168.1.6 ip dhcp excluded-address 192.168.1.8 ip dhcp excluded-address 192.168.3.1 ! ip dhcp pool ccp-pool import all network 192.168.1.0 255.255.255.0 default-router 192.168.1.1 dns-server 10.171.12.5 10.171.12.37 lease 0 2 ! ip dhcp pool guest import all network 192.168.3.0 255.255.255.0 default-router 192.168.3.1 dns-server 10.171.12.5 10.171.12.37 ! ! ip cef no ip domain lookup no ipv6 cef ! ! multilink bundle-name authenticated license udi pid CISCO891W-AGN-A-K9 sn FTX153085WL ! ! username ESIadmin privilege 15 secret 5 $1$g1..$JSZ0qxljZAgJJIk/anDu51 username user1 password 0 pass ! ! ! class-map type inspect match-any ccp-cls-insp-traffic match protocol cuseeme match protocol dns match protocol ftp match protocol h323 match protocol https match protocol icmp match protocol imap match protocol pop3 match protocol netshow match protocol shell match protocol realmedia match protocol rtsp match protocol smtp match protocol sql-net match protocol streamworks match protocol tftp match protocol vdolive match protocol tcp match protocol udp class-map type inspect match-all ccp-insp-traffic match class-map ccp-cls-insp-traffic class-map type inspect match-any ccp-cls-icmp-access match protocol icmp class-map type inspect match-all ccp-invalid-src match access-group 100 class-map type inspect match-all ccp-icmp-access match class-map ccp-cls-icmp-access class-map type inspect match-all ccp-protocol-http match protocol http ! ! policy-map type inspect ccp-permit-icmpreply class type inspect ccp-icmp-access inspect class class-default pass policy-map type inspect ccp-inspect class type inspect ccp-invalid-src drop log class type inspect ccp-protocol-http inspect class type inspect ccp-insp-traffic inspect class class-default drop policy-map type inspect ccp-permit class class-default drop ! zone security out-zone zone security in-zone zone-pair security ccp-zp-self-out source self destination out-zone service-policy type inspect ccp-permit-icmpreply zone-pair security ccp-zp-in-out source in-zone destination out-zone service-policy type inspect ccp-inspect zone-pair security ccp-zp-out-self source out-zone destination self service-policy type inspect ccp-permit ! ! crypto isakmp policy 1 encr 3des authentication pre-share group 2 ! crypto isakmp client configuration group 3000client key 67Nif8LLmqP_ dns 10.171.12.37 10.171.12.5 pool dynpool acl 101 ! ! crypto ipsec transform-set myset esp-3des esp-sha-hmac ! crypto dynamic-map dynmap 10 set transform-set myset ! ! crypto map clientmap client authentication list userauthen crypto map clientmap isakmp authorization list groupauthor crypto map clientmap client configuration address initiate crypto map clientmap client configuration address respond crypto map clientmap 10 ipsec-isakmp dynamic dynmap ! ! ! ! ! interface FastEthernet0 ! ! interface FastEthernet1 ! ! interface FastEthernet2 ! ! interface FastEthernet3 ! ! interface FastEthernet4 ! ! interface FastEthernet5 ! ! interface FastEthernet6 ! ! interface FastEthernet7 ! ! interface FastEthernet8 ip address dhcp ip nat outside ip virtual-reassembly duplex auto speed auto ! ! interface GigabitEthernet0 description $FW_OUTSIDE$$ES_WAN$ ip address 10...* 255.255.254.0 ip nat outside ip virtual-reassembly zone-member security out-zone duplex auto speed auto crypto map clientmap ! ! interface wlan-ap0 description Service module interface to manage the embedded AP ip unnumbered Vlan1 arp timeout 0 ! ! interface Wlan-GigabitEthernet0 description Internal switch interface connecting to the embedded AP switchport trunk allowed vlan 1-3,1002-1005 switchport mode trunk ! ! interface Vlan1 description $ETH-SW-LAUNCH$$INTF-INFO-FE 1$$FW_INSIDE$ ip address 192.168.1.1 255.255.255.0 ip nat inside ip virtual-reassembly zone-member security in-zone ip tcp adjust-mss 1452 crypto map clientmap ! ! interface Vlan2 description guest ip address 192.168.3.1 255.255.255.0 ip access-group 120 in ip nat inside ip virtual-reassembly zone-member security in-zone ! ! interface Async1 no ip address encapsulation slip ! ! ip local pool dynpool 192.168.1.200 192.168.1.210 ip forward-protocol nd ip http server ip http access-class 23 ip http authentication local ip http secure-server ip http timeout-policy idle 60 life 86400 requests 10000 ! ! ip dns server ip nat inside source list 23 interface GigabitEthernet0 overload ip route 0.0.0.0 0.0.0.0 10.165.0.1 ! access-list 23 permit 192.168.1.0 0.0.0.255 access-list 100 remark CCP_ACL Category=128 access-list 100 permit ip host 255.255.255.255 any access-list 100 permit ip 127.0.0.0 0.255.255.255 any access-list 100 permit ip 10.165.0.0 0.0.1.255 any access-list 110 permit ip 192.168.0.0 0.0.5.255 any access-list 120 remark ESIGuest Restriction no cdp run ! ! ! ! ! ! control-plane ! ! alias exec dot11radio service-module wlan-ap 0 session Access point version 12.4 no service pad service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname ESIRouter ! no logging console enable secret 5 $1$yEH5$CxI5.9ypCBa6kXrUnSuvp1 ! aaa new-model ! ! aaa group server radius rad_eap server 192.168.1.5 auth-port 1812 acct-port 1813 ! aaa group server radius rad_acct server 192.168.1.5 auth-port 1812 acct-port 1813 ! aaa authentication login eap_methods group rad_eap aaa authentication enable default line enable aaa authorization exec default local aaa authorization commands 15 default local aaa accounting network acct_methods start-stop group rad_acct ! aaa session-id common clock timezone EST -5 clock summer-time EDT recurring ip domain name ESI ! ! dot11 syslog dot11 vlan-name one vlan 1 dot11 vlan-name two vlan 2 ! dot11 ssid one vlan 1 authentication open eap eap_methods authentication network-eap eap_methods authentication key-management wpa version 2 accounting rad_acct ! dot11 ssid two vlan 2 authentication open guest-mode ! dot11 network-map ! ! username ESIadmin privilege 15 secret 5 $1$p02C$WVHr5yKtRtQxuFxPU8NOx. ! ! bridge irb ! ! interface Dot11Radio0 no ip address no ip route-cache ! encryption vlan 1 mode ciphers aes-ccm ! broadcast-key vlan 1 change 30 ! ! ssid one ! ssid two ! antenna gain 0 station-role root ! interface Dot11Radio0.1 encapsulation dot1Q 1 native no ip route-cache bridge-group 1 bridge-group 1 subscriber-loop-control bridge-group 1 block-unknown-source no bridge-group 1 source-learning no bridge-group 1 unicast-flooding bridge-group 1 spanning-disabled ! interface Dot11Radio0.2 encapsulation dot1Q 2 no ip route-cache bridge-group 2 bridge-group 2 subscriber-loop-control bridge-group 2 block-unknown-source no bridge-group 2 source-learning no bridge-group 2 unicast-flooding bridge-group 2 spanning-disabled ! interface Dot11Radio1 no ip address no ip route-cache shutdown ! encryption vlan 1 mode ciphers aes-ccm ! broadcast-key vlan 1 change 30 ! ! ssid one ! antenna gain 0 dfs band 3 block channel dfs station-role root ! interface Dot11Radio1.1 encapsulation dot1Q 1 native no ip route-cache bridge-group 1 bridge-group 1 subscriber-loop-control bridge-group 1 block-unknown-source no bridge-group 1 source-learning no bridge-group 1 unicast-flooding bridge-group 1 spanning-disabled ! interface GigabitEthernet0 description the embedded AP GigabitEthernet 0 is an internal interface connecting AP with the host router no ip address no ip route-cache ! interface GigabitEthernet0.1 encapsulation dot1Q 1 native no ip route-cache bridge-group 1 no bridge-group 1 source-learning bridge-group 1 spanning-disabled ! interface GigabitEthernet0.2 encapsulation dot1Q 2 no ip route-cache bridge-group 2 no bridge-group 2 source-learning bridge-group 2 spanning-disabled ! interface BVI1 ip address 192.168.1.2 255.255.255.0 no ip route-cache ! ip http server no ip http secure-server ip http help-path http://www.cisco.com/warp/public/779/smbiz/prodconfig/help/eag access-list 10 permit 192.168.1.0 0.0.0.255 radius-server host 192.168.1.5 auth-port 1812 acct-port 1813 key ***** bridge 1 route ip

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  • Inbound SIP calls through Cisco 881 NAT hang up after a few seconds

    - by MasterRoot24
    I've recently moved to a Cisco 881 router for my WAN link. I was previously using a Cisco Linksys WAG320N as my modem/router/WiFi AP/NAT firewall. The WAG320N is now running in bridged mode, so it's simply acting as a modem with one of it's LAN ports connected to FE4 WAN on my Cisco 881. The Cisco 881 get's a DHCP provided IP from my ISP. My LAN is part of default Vlan 1 (192.168.1.0/24). General internet connectivity is working great, I've managed to setup static NAT rules for my HTTP/HTTPS/SMTP/etc. services which are running on my LAN. I don't know whether it's worth mentioning that I've opted to use NVI NAT (ip nat enable as opposed to the traditional ip nat outside/ip nat inside) setup. My reason for this is that NVI allows NAT loopback from my LAN to the WAN IP and back in to the necessary server on the LAN. I run an Asterisk 1.8 PBX on my LAN, which connects to a SIP provider on the internet. Both inbound and outbound calls through the old setup (WAG320N providing routing/NAT) worked fine. However, since moving to the Cisco 881, inbound calls drop after around 10 seconds, whereas outbound calls work fine. The following message is logged on my Asterisk PBX: [Dec 9 15:27:45] WARNING[27734]: chan_sip.c:3641 retrans_pkt: Retransmission timeout reached on transmission [email protected] for seqno 1 (Critical Response) -- See https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions Packet timed out after 6528ms with no response [Dec 9 15:27:45] WARNING[27734]: chan_sip.c:3670 retrans_pkt: Hanging up call [email protected] - no reply to our critical packet (see https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions). (I know that this is quite a common issue - I've spend the best part of 2 days solid on this, trawling Google.) I've done as I am told and checked https://wiki.asterisk.org/wiki/display/AST/SIP+Retransmissions. Referring to the section "Other SIP requests" in the page linked above, I believe that the hangup to be caused by the ACK from my SIP provider not being passed back through NAT to Asterisk on my PBX. I tried to ascertain this by dumping the packets on my WAN interface on the 881. I managed to obtain a PCAP dump of packets in/out of my WAN interface. Here's an example of an ACK being reveived by the router from my provider: 689 21.219999 193.x.x.x 188.x.x.x SIP 502 Request: ACK sip:[email protected] | However a SIP trace on the Asterisk server show's that there are no ACK's received in response to the 200 OK from my PBX: http://pastebin.com/wwHpLPPz In the past, I have been strongly advised to disable any sort of SIP ALGs on routers and/or firewalls and the many posts regarding this issue on the internet seem to support this. However, I believe on Cisco IOS, the config command to disable SIP ALG is no ip nat service sip udp port 5060 however, this doesn't appear to help the situation. To confirm that config setting is set: Router1#show running-config | include sip no ip nat service sip udp port 5060 Another interesting twist: for a short period of time, I tried another provider. Luckily, my trial account with them is still available, so I reverted my Asterisk config back to the revision before I integrated with my current provider. I then dialled in to the DDI associated with the trial trunk and the call didn't get hung up and I didn't get the error above! To me, this points at the provider, however I know, like all providers do, will say "There's no issues with our SIP proxies - it's your firewall." I'm tempted to agree with this, as this issue was not apparent with the old WAG320N router when it was doing the NAT'ing. I'm sure you'll want to see my running-config too: ! ! Last configuration change at 15:55:07 UTC Sun Dec 9 2012 by xxx version 15.2 no service pad service tcp-keepalives-in service tcp-keepalives-out service timestamps debug datetime msec localtime show-timezone service timestamps log datetime msec localtime show-timezone no service password-encryption service sequence-numbers ! hostname Router1 ! boot-start-marker boot-end-marker ! ! security authentication failure rate 10 log security passwords min-length 6 logging buffered 4096 logging console critical enable secret 4 xxx ! aaa new-model ! ! aaa authentication login local_auth local ! ! ! ! ! aaa session-id common ! memory-size iomem 10 ! crypto pki trustpoint TP-self-signed-xxx enrollment selfsigned subject-name cn=IOS-Self-Signed-Certificate-xxx revocation-check none rsakeypair TP-self-signed-xxx ! ! crypto pki certificate chain TP-self-signed-xxx certificate self-signed 01 quit no ip source-route no ip gratuitous-arps ip auth-proxy max-login-attempts 5 ip admission max-login-attempts 5 ! ! ! ! ! no ip bootp server ip domain name dmz.merlin.local ip domain list dmz.merlin.local ip domain list merlin.local ip name-server x.x.x.x ip inspect audit-trail ip inspect udp idle-time 1800 ip inspect dns-timeout 7 ip inspect tcp idle-time 14400 ip inspect name autosec_inspect ftp timeout 3600 ip inspect name autosec_inspect http timeout 3600 ip inspect name autosec_inspect rcmd timeout 3600 ip inspect name autosec_inspect realaudio timeout 3600 ip inspect name autosec_inspect smtp timeout 3600 ip inspect name autosec_inspect tftp timeout 30 ip inspect name autosec_inspect udp timeout 15 ip inspect name autosec_inspect tcp timeout 3600 ip cef login block-for 3 attempts 3 within 3 no ipv6 cef ! ! multilink bundle-name authenticated license udi pid CISCO881-SEC-K9 sn ! ! username xxx privilege 15 secret 4 xxx username xxx secret 4 xxx ! ! ! ! ! ip ssh time-out 60 ! ! ! ! ! ! ! ! ! interface FastEthernet0 no ip address ! interface FastEthernet1 no ip address ! interface FastEthernet2 no ip address ! interface FastEthernet3 switchport access vlan 2 no ip address ! interface FastEthernet4 ip address dhcp no ip redirects no ip unreachables no ip proxy-arp ip nat enable duplex auto speed auto ! interface Vlan1 ip address 192.168.1.1 255.255.255.0 no ip redirects no ip unreachables no ip proxy-arp ip nat enable ! interface Vlan2 ip address 192.168.0.2 255.255.255.0 ! ip forward-protocol nd ip http server ip http access-class 1 ip http authentication local ip http secure-server ip http timeout-policy idle 60 life 86400 requests 10000 ! ! no ip nat service sip udp port 5060 ip nat source list 1 interface FastEthernet4 overload ip nat source static tcp x.x.x.x 80 interface FastEthernet4 80 ip nat source static tcp x.x.x.x 443 interface FastEthernet4 443 ip nat source static tcp x.x.x.x 25 interface FastEthernet4 25 ip nat source static tcp x.x.x.x 587 interface FastEthernet4 587 ip nat source static tcp x.x.x.x 143 interface FastEthernet4 143 ip nat source static tcp x.x.x.x 993 interface FastEthernet4 993 ip nat source static tcp x.x.x.x 1723 interface FastEthernet4 1723 ! ! logging trap debugging logging facility local2 access-list 1 permit 192.168.1.0 0.0.0.255 access-list 1 permit 192.168.0.0 0.0.0.255 no cdp run ! ! ! ! control-plane ! ! banner motd Authorized Access only ! line con 0 login authentication local_auth length 0 transport output all line aux 0 exec-timeout 15 0 login authentication local_auth transport output all line vty 0 1 access-class 1 in logging synchronous login authentication local_auth length 0 transport preferred none transport input telnet transport output all line vty 2 4 access-class 1 in login authentication local_auth length 0 transport input ssh transport output all ! ! end ...and, if it's of any use, here's my Asterisk SIP config: [general] context=default ; Default context for calls allowoverlap=no ; Disable overlap dialing support. (Default is yes) udpbindaddr=0.0.0.0 ; IP address to bind UDP listen socket to (0.0.0.0 binds to all) ; Optionally add a port number, 192.168.1.1:5062 (default is port 5060) tcpenable=no ; Enable server for incoming TCP connections (default is no) tcpbindaddr=0.0.0.0 ; IP address for TCP server to bind to (0.0.0.0 binds to all interfaces) ; Optionally add a port number, 192.168.1.1:5062 (default is port 5060) srvlookup=yes ; Enable DNS SRV lookups on outbound calls ; Note: Asterisk only uses the first host ; in SRV records ; Disabling DNS SRV lookups disables the ; ability to place SIP calls based on domain ; names to some other SIP users on the Internet ; Specifying a port in a SIP peer definition or ; when dialing outbound calls will supress SRV ; lookups for that peer or call. directmedia=no ; Don't allow direct RTP media between extensions (doesn't work through NAT) externhost=<MY DYNDNS HOSTNAME> ; Our external hostname to resolve to IP and be used in NAT'ed packets localnet=192.168.1.0/24 ; Define our local network so we know which packets need NAT'ing qualify=yes ; Qualify peers by default dtmfmode=rfc2833 ; Set the default DTMF mode disallow=all ; Disallow all codecs by default allow=ulaw ; Allow G.711 u-law allow=alaw ; Allow G.711 a-law ; ---------------------- ; SIP Trunk Registration ; ---------------------- ; Orbtalk register => <MY SIP PROVIDER USER NAME>:[email protected]/<MY DDI> ; Main Orbtalk number ; ---------- ; Trunks ; ---------- [orbtalk] ; Main Orbtalk trunk type=peer insecure=invite host=sipgw3.orbtalk.co.uk nat=yes username=<MY SIP PROVIDER USER NAME> defaultuser=<MY SIP PROVIDER USER NAME> fromuser=<MY SIP PROVIDER USER NAME> secret=xxx context=inbound I really don't know where to go with this. If anyone can help me find out why these calls are being dropped off, I'd be grateful if you could chime in! Please let me know if any further info is required.

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  • Bacula & Multiple Tape Devices, and so on

    - by Tom O'Connor
    Bacula won't make use of 2 tape devices simultaneously. (Search for #-#-# for the TL;DR) A little background, perhaps. In the process of trying to get a decent working backup solution (backing up 20TB ain't cheap, or easy) at $dayjob, we bought a bunch of things to make it work. Firstly, there's a Spectra Logic T50e autochanger, 40 slots of LTO5 goodness, and that robot's got a pair of IBM HH5 Ultrium LTO5 drives, connected via FibreChannel Arbitrated Loop to our backup server. There's the backup server.. A Dell R715 with 2x 16 core AMD 62xx CPUs, and 32GB of RAM. Yummy. That server's got 2 Emulex FCe-12000E cards, and an Intel X520-SR dual port 10GE NIC. We were also sold Commvault Backup (non-NDMP). Here's where it gets really complicated. Spectra Logic and Commvault both sent respective engineers, who set up the library and the software. Commvault was running fine, in so far as the controller was working fine. The Dell server has Ubuntu 12.04 server, and runs the MediaAgent for CommVault, and mounts our BlueArc NAS as NFS to a few mountpoints, like /home, and some stuff in /mnt. When backing up from the NFS mountpoints, we were seeing ~= 290GB/hr throughput. That's CRAP, considering we've got 20-odd TB to get through, in a <48 hour backup window. The rated maximum on the BlueArc is 700MB/s (2460GB/hr), the rated maximum write speed on the tape devices is 140MB/s, per drive, so that's 492GB/hr (or double it, for the total throughput). So, the next step was to benchmark NFS performance with IOzone, and it turns out that we get epic write performance (across 20 threads), and it's like 1.5-2.5TB/hr write, but read performance is fecking hopeless. I couldn't ever get higher than 343GB/hr maximum. So let's assume that the 343GB/hr is a theoretical maximum for read performance on the NAS, then we should in theory be able to get that performance out of a) CommVault, and b) any other backup agent. Not the case. Commvault seems to only ever give me 200-250GB/hr throughput, and out of experimentation, I installed Bacula to see what the state of play there is. If, for example, Bacula gave consistently better performance and speeds than Commvault, then we'd be able to say "**$.$ Refunds Plz $.$**" #-#-# Alas, I found a different problem with Bacula. Commvault seems pretty happy to read from one part of the mountpoint with one thread, and stream that to a Tape device, whilst reading from some other directory with the other thread, and writing to the 2nd drive in the autochanger. I can't for the life of me get Bacula to mount and write to two tape drives simultaneously. Things I've tried: Setting Maximum Concurrent Jobs = 20 in the Director, File and Storage Daemons Setting Prefer Mounted Volumes = no in the Job Definition Setting multiple devices in the Autochanger resource. Documentation seems to be very single-drive centric, and we feel a little like we've strapped a rocket to a hamster, with this one. The majority of example Bacula configurations are for DDS4 drives, manual tape swapping, and FreeBSD or IRIX systems. I should probably add that I'm not too bothered if this isn't possible, but I'd be surprised. I basically want to use Bacula as proof to stick it to the software vendors that they're overpriced ;) I read somewhere that @KyleBrandt has done something similar with a modern Tape solution.. Configuration Files: *bacula-dir.conf* # # Default Bacula Director Configuration file Director { # define myself Name = backuphost-1-dir DIRport = 9101 # where we listen for UA connections QueryFile = "/etc/bacula/scripts/query.sql" WorkingDirectory = "/var/lib/bacula" PidDirectory = "/var/run/bacula" Maximum Concurrent Jobs = 20 Password = "yourekiddingright" # Console password Messages = Daemon DirAddress = 0.0.0.0 #DirAddress = 127.0.0.1 } JobDefs { Name = "DefaultFileJob" Type = Backup Level = Incremental Client = backuphost-1-fd FileSet = "Full Set" Schedule = "WeeklyCycle" Storage = File Messages = Standard Pool = File Priority = 10 Write Bootstrap = "/var/lib/bacula/%c.bsr" } JobDefs { Name = "DefaultTapeJob" Type = Backup Level = Incremental Client = backuphost-1-fd FileSet = "Full Set" Schedule = "WeeklyCycle" Storage = "SpectraLogic" Messages = Standard Pool = AllTapes Priority = 10 Write Bootstrap = "/var/lib/bacula/%c.bsr" Prefer Mounted Volumes = no } # # Define the main nightly save backup job # By default, this job will back up to disk in /nonexistant/path/to/file/archive/dir Job { Name = "BackupClient1" JobDefs = "DefaultFileJob" } Job { Name = "BackupThisVolume" JobDefs = "DefaultTapeJob" FileSet = "SpecialVolume" } #Job { # Name = "BackupClient2" # Client = backuphost-12-fd # JobDefs = "DefaultJob" #} # Backup the catalog database (after the nightly save) Job { Name = "BackupCatalog" JobDefs = "DefaultFileJob" Level = Full FileSet="Catalog" Schedule = "WeeklyCycleAfterBackup" # This creates an ASCII copy of the catalog # Arguments to make_catalog_backup.pl are: # make_catalog_backup.pl <catalog-name> RunBeforeJob = "/etc/bacula/scripts/make_catalog_backup.pl MyCatalog" # This deletes the copy of the catalog RunAfterJob = "/etc/bacula/scripts/delete_catalog_backup" Write Bootstrap = "/var/lib/bacula/%n.bsr" Priority = 11 # run after main backup } # # Standard Restore template, to be changed by Console program # Only one such job is needed for all Jobs/Clients/Storage ... # Job { Name = "RestoreFiles" Type = Restore Client=backuphost-1-fd FileSet="Full Set" Storage = File Pool = Default Messages = Standard Where = /srv/bacula/restore } FileSet { Name = "SpecialVolume" Include { Options { signature = MD5 } File = /mnt/SpecialVolume } Exclude { File = /var/lib/bacula File = /nonexistant/path/to/file/archive/dir File = /proc File = /tmp File = /.journal File = /.fsck } } # List of files to be backed up FileSet { Name = "Full Set" Include { Options { signature = MD5 } File = /usr/sbin } Exclude { File = /var/lib/bacula File = /nonexistant/path/to/file/archive/dir File = /proc File = /tmp File = /.journal File = /.fsck } } Schedule { Name = "WeeklyCycle" Run = Full 1st sun at 23:05 Run = Differential 2nd-5th sun at 23:05 Run = Incremental mon-sat at 23:05 } # This schedule does the catalog. It starts after the WeeklyCycle Schedule { Name = "WeeklyCycleAfterBackup" Run = Full sun-sat at 23:10 } # This is the backup of the catalog FileSet { Name = "Catalog" Include { Options { signature = MD5 } File = "/var/lib/bacula/bacula.sql" } } # Client (File Services) to backup Client { Name = backuphost-1-fd Address = localhost FDPort = 9102 Catalog = MyCatalog Password = "surelyyourejoking" # password for FileDaemon File Retention = 30 days # 30 days Job Retention = 6 months # six months AutoPrune = yes # Prune expired Jobs/Files } # # Second Client (File Services) to backup # You should change Name, Address, and Password before using # #Client { # Name = backuphost-12-fd # Address = localhost2 # FDPort = 9102 # Catalog = MyCatalog # Password = "i'mnotjokinganddontcallmeshirley" # password for FileDaemon 2 # File Retention = 30 days # 30 days # Job Retention = 6 months # six months # AutoPrune = yes # Prune expired Jobs/Files #} # Definition of file storage device Storage { Name = File # Do not use "localhost" here Address = localhost # N.B. Use a fully qualified name here SDPort = 9103 Password = "lalalalala" Device = FileStorage Media Type = File } Storage { Name = "SpectraLogic" Address = localhost SDPort = 9103 Password = "linkedinmakethebestpasswords" Device = Drive-1 Device = Drive-2 Media Type = LTO5 Autochanger = yes } # Generic catalog service Catalog { Name = MyCatalog # Uncomment the following line if you want the dbi driver # dbdriver = "dbi:sqlite3"; dbaddress = 127.0.0.1; dbport = dbname = "bacula"; DB Address = ""; dbuser = "bacula"; dbpassword = "bbmaster63" } # Reasonable message delivery -- send most everything to email address # and to the console Messages { Name = Standard mailcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula: %t %e of %c %l\" %r" operatorcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula: Intervention needed for %j\" %r" mail = root@localhost = all, !skipped operator = root@localhost = mount console = all, !skipped, !saved # # WARNING! the following will create a file that you must cycle from # time to time as it will grow indefinitely. However, it will # also keep all your messages if they scroll off the console. # append = "/var/lib/bacula/log" = all, !skipped catalog = all } # # Message delivery for daemon messages (no job). Messages { Name = Daemon mailcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula daemon message\" %r" mail = root@localhost = all, !skipped console = all, !skipped, !saved append = "/var/lib/bacula/log" = all, !skipped } # Default pool definition Pool { Name = Default Pool Type = Backup Recycle = yes # Bacula can automatically recycle Volumes AutoPrune = yes # Prune expired volumes Volume Retention = 365 days # one year } # File Pool definition Pool { Name = File Pool Type = Backup Recycle = yes # Bacula can automatically recycle Volumes AutoPrune = yes # Prune expired volumes Volume Retention = 365 days # one year Maximum Volume Bytes = 50G # Limit Volume size to something reasonable Maximum Volumes = 100 # Limit number of Volumes in Pool } Pool { Name = AllTapes Pool Type = Backup Recycle = yes AutoPrune = yes # Prune expired volumes Volume Retention = 31 days # one Moth } # Scratch pool definition Pool { Name = Scratch Pool Type = Backup } # # Restricted console used by tray-monitor to get the status of the director # Console { Name = backuphost-1-mon Password = "LastFMalsostorePasswordsLikeThis" CommandACL = status, .status } bacula-sd.conf # # Default Bacula Storage Daemon Configuration file # Storage { # definition of myself Name = backuphost-1-sd SDPort = 9103 # Director's port WorkingDirectory = "/var/lib/bacula" Pid Directory = "/var/run/bacula" Maximum Concurrent Jobs = 20 SDAddress = 0.0.0.0 # SDAddress = 127.0.0.1 } # # List Directors who are permitted to contact Storage daemon # Director { Name = backuphost-1-dir Password = "passwordslinplaintext" } # # Restricted Director, used by tray-monitor to get the # status of the storage daemon # Director { Name = backuphost-1-mon Password = "totalinsecurityabound" Monitor = yes } Device { Name = FileStorage Media Type = File Archive Device = /srv/bacula/archive LabelMedia = yes; # lets Bacula label unlabeled media Random Access = Yes; AutomaticMount = yes; # when device opened, read it RemovableMedia = no; AlwaysOpen = no; } Autochanger { Name = SpectraLogic Device = Drive-1 Device = Drive-2 Changer Command = "/etc/bacula/scripts/mtx-changer %c %o %S %a %d" Changer Device = /dev/sg4 } Device { Name = Drive-1 Drive Index = 0 Archive Device = /dev/nst0 Changer Device = /dev/sg4 Media Type = LTO5 AutoChanger = yes RemovableMedia = yes; AutomaticMount = yes; AlwaysOpen = yes; RandomAccess = no; LabelMedia = yes } Device { Name = Drive-2 Drive Index = 1 Archive Device = /dev/nst1 Changer Device = /dev/sg4 Media Type = LTO5 AutoChanger = yes RemovableMedia = yes; AutomaticMount = yes; AlwaysOpen = yes; RandomAccess = no; LabelMedia = yes } # # Send all messages to the Director, # mount messages also are sent to the email address # Messages { Name = Standard director = backuphost-1-dir = all } bacula-fd.conf # # Default Bacula File Daemon Configuration file # # # List Directors who are permitted to contact this File daemon # Director { Name = backuphost-1-dir Password = "hahahahahaha" } # # Restricted Director, used by tray-monitor to get the # status of the file daemon # Director { Name = backuphost-1-mon Password = "hohohohohho" Monitor = yes } # # "Global" File daemon configuration specifications # FileDaemon { # this is me Name = backuphost-1-fd FDport = 9102 # where we listen for the director WorkingDirectory = /var/lib/bacula Pid Directory = /var/run/bacula Maximum Concurrent Jobs = 20 #FDAddress = 127.0.0.1 FDAddress = 0.0.0.0 } # Send all messages except skipped files back to Director Messages { Name = Standard director = backuphost-1-dir = all, !skipped, !restored }

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  • Unusually high dentry cache usage

    - by Wolfgang Stengel
    Problem A CentOS machine with kernel 2.6.32 and 128 GB physical RAM ran into trouble a few days ago. The responsible system administrator tells me that the PHP-FPM application was not responding to requests in a timely manner anymore due to swapping, and having seen in free that almost no memory was left, he chose to reboot the machine. I know that free memory can be a confusing concept on Linux and a reboot perhaps was the wrong thing to do. However, the mentioned administrator blames the PHP application (which I am responsible for) and refuses to investigate further. What I could find out on my own is this: Before the restart, the free memory (incl. buffers and cache) was only a couple of hundred MB. Before the restart, /proc/meminfo reported a Slab memory usage of around 90 GB (yes, GB). After the restart, the free memory was 119 GB, going down to around 100 GB within an hour, as the PHP-FPM workers (about 600 of them) were coming back to life, each of them showing between 30 and 40 MB in the RES column in top (which has been this way for months and is perfectly reasonable given the nature of the PHP application). There is nothing else in the process list that consumes an unusual or noteworthy amount of RAM. After the restart, Slab memory was around 300 MB If have been monitoring the system ever since, and most notably the Slab memory is increasing in a straight line with a rate of about 5 GB per day. Free memory as reported by free and /proc/meminfo decreases at the same rate. Slab is currently at 46 GB. According to slabtop most of it is used for dentry entries: Free memory: free -m total used free shared buffers cached Mem: 129048 76435 52612 0 144 7675 -/+ buffers/cache: 68615 60432 Swap: 8191 0 8191 Meminfo: cat /proc/meminfo MemTotal: 132145324 kB MemFree: 53620068 kB Buffers: 147760 kB Cached: 8239072 kB SwapCached: 0 kB Active: 20300940 kB Inactive: 6512716 kB Active(anon): 18408460 kB Inactive(anon): 24736 kB Active(file): 1892480 kB Inactive(file): 6487980 kB Unevictable: 8608 kB Mlocked: 8608 kB SwapTotal: 8388600 kB SwapFree: 8388600 kB Dirty: 11416 kB Writeback: 0 kB AnonPages: 18436224 kB Mapped: 94536 kB Shmem: 6364 kB Slab: 46240380 kB SReclaimable: 44561644 kB SUnreclaim: 1678736 kB KernelStack: 9336 kB PageTables: 457516 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 72364108 kB Committed_AS: 22305444 kB VmallocTotal: 34359738367 kB VmallocUsed: 480164 kB VmallocChunk: 34290830848 kB HardwareCorrupted: 0 kB AnonHugePages: 12216320 kB HugePages_Total: 2048 HugePages_Free: 2048 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 5604 kB DirectMap2M: 2078720 kB DirectMap1G: 132120576 kB Slabtop: slabtop --once Active / Total Objects (% used) : 225920064 / 226193412 (99.9%) Active / Total Slabs (% used) : 11556364 / 11556415 (100.0%) Active / Total Caches (% used) : 110 / 194 (56.7%) Active / Total Size (% used) : 43278793.73K / 43315465.42K (99.9%) Minimum / Average / Maximum Object : 0.02K / 0.19K / 4096.00K OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 221416340 221416039 3% 0.19K 11070817 20 44283268K dentry 1123443 1122739 99% 0.41K 124827 9 499308K fuse_request 1122320 1122180 99% 0.75K 224464 5 897856K fuse_inode 761539 754272 99% 0.20K 40081 19 160324K vm_area_struct 437858 223259 50% 0.10K 11834 37 47336K buffer_head 353353 347519 98% 0.05K 4589 77 18356K anon_vma_chain 325090 324190 99% 0.06K 5510 59 22040K size-64 146272 145422 99% 0.03K 1306 112 5224K size-32 137625 137614 99% 1.02K 45875 3 183500K nfs_inode_cache 128800 118407 91% 0.04K 1400 92 5600K anon_vma 59101 46853 79% 0.55K 8443 7 33772K radix_tree_node 52620 52009 98% 0.12K 1754 30 7016K size-128 19359 19253 99% 0.14K 717 27 2868K sysfs_dir_cache 10240 7746 75% 0.19K 512 20 2048K filp VFS cache pressure: cat /proc/sys/vm/vfs_cache_pressure 125 Swappiness: cat /proc/sys/vm/swappiness 0 I know that unused memory is wasted memory, so this should not necessarily be a bad thing (especially given that 44 GB are shown as SReclaimable). However, apparently the machine experienced problems nonetheless, and I'm afraid the same will happen again in a few days when Slab surpasses 90 GB. Questions I have these questions: Am I correct in thinking that the Slab memory is always physical RAM, and the number is already subtracted from the MemFree value? Is such a high number of dentry entries normal? The PHP application has access to around 1.5 M files, however most of them are archives and not being accessed at all for regular web traffic. What could be an explanation for the fact that the number of cached inodes is much lower than the number of cached dentries, should they not be related somehow? If the system runs into memory trouble, should the kernel not free some of the dentries automatically? What could be a reason that this does not happen? Is there any way to "look into" the dentry cache to see what all this memory is (i.e. what are the paths that are being cached)? Perhaps this points to some kind of memory leak, symlink loop, or indeed to something the PHP application is doing wrong. The PHP application code as well as all asset files are mounted via GlusterFS network file system, could that have something to do with it? Please keep in mind that I can not investigate as root, only as a regular user, and that the administrator refuses to help. He won't even run the typical echo 2 > /proc/sys/vm/drop_caches test to see if the Slab memory is indeed reclaimable. Any insights into what could be going on and how I can investigate any further would be greatly appreciated. Updates Some further diagnostic information: Mounts: cat /proc/self/mounts rootfs / rootfs rw 0 0 proc /proc proc rw,relatime 0 0 sysfs /sys sysfs rw,relatime 0 0 devtmpfs /dev devtmpfs rw,relatime,size=66063000k,nr_inodes=16515750,mode=755 0 0 devpts /dev/pts devpts rw,relatime,gid=5,mode=620,ptmxmode=000 0 0 tmpfs /dev/shm tmpfs rw,relatime 0 0 /dev/mapper/sysvg-lv_root / ext4 rw,relatime,barrier=1,data=ordered 0 0 /proc/bus/usb /proc/bus/usb usbfs rw,relatime 0 0 /dev/sda1 /boot ext4 rw,relatime,barrier=1,data=ordered 0 0 tmpfs /phptmp tmpfs rw,noatime,size=1048576k,nr_inodes=15728640,mode=777 0 0 tmpfs /wsdltmp tmpfs rw,noatime,size=1048576k,nr_inodes=15728640,mode=777 0 0 none /proc/sys/fs/binfmt_misc binfmt_misc rw,relatime 0 0 cgroup /cgroup/cpuset cgroup rw,relatime,cpuset 0 0 cgroup /cgroup/cpu cgroup rw,relatime,cpu 0 0 cgroup /cgroup/cpuacct cgroup rw,relatime,cpuacct 0 0 cgroup /cgroup/memory cgroup rw,relatime,memory 0 0 cgroup /cgroup/devices cgroup rw,relatime,devices 0 0 cgroup /cgroup/freezer cgroup rw,relatime,freezer 0 0 cgroup /cgroup/net_cls cgroup rw,relatime,net_cls 0 0 cgroup /cgroup/blkio cgroup rw,relatime,blkio 0 0 /etc/glusterfs/glusterfs-www.vol /var/www fuse.glusterfs rw,relatime,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072 0 0 /etc/glusterfs/glusterfs-upload.vol /var/upload fuse.glusterfs rw,relatime,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072 0 0 sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0 172.17.39.78:/www /data/www nfs rw,relatime,vers=3,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,port=38467,timeo=600,retrans=2,sec=sys,mountaddr=172.17.39.78,mountvers=3,mountport=38465,mountproto=tcp,local_lock=none,addr=172.17.39.78 0 0 Mount info: cat /proc/self/mountinfo 16 21 0:3 / /proc rw,relatime - proc proc rw 17 21 0:0 / /sys rw,relatime - sysfs sysfs rw 18 21 0:5 / /dev rw,relatime - devtmpfs devtmpfs rw,size=66063000k,nr_inodes=16515750,mode=755 19 18 0:11 / /dev/pts rw,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=000 20 18 0:16 / /dev/shm rw,relatime - tmpfs tmpfs rw 21 1 253:1 / / rw,relatime - ext4 /dev/mapper/sysvg-lv_root rw,barrier=1,data=ordered 22 16 0:15 / /proc/bus/usb rw,relatime - usbfs /proc/bus/usb rw 23 21 8:1 / /boot rw,relatime - ext4 /dev/sda1 rw,barrier=1,data=ordered 24 21 0:17 / /phptmp rw,noatime - tmpfs tmpfs rw,size=1048576k,nr_inodes=15728640,mode=777 25 21 0:18 / /wsdltmp rw,noatime - tmpfs tmpfs rw,size=1048576k,nr_inodes=15728640,mode=777 26 16 0:19 / /proc/sys/fs/binfmt_misc rw,relatime - binfmt_misc none rw 27 21 0:20 / /cgroup/cpuset rw,relatime - cgroup cgroup rw,cpuset 28 21 0:21 / /cgroup/cpu rw,relatime - cgroup cgroup rw,cpu 29 21 0:22 / /cgroup/cpuacct rw,relatime - cgroup cgroup rw,cpuacct 30 21 0:23 / /cgroup/memory rw,relatime - cgroup cgroup rw,memory 31 21 0:24 / /cgroup/devices rw,relatime - cgroup cgroup rw,devices 32 21 0:25 / /cgroup/freezer rw,relatime - cgroup cgroup rw,freezer 33 21 0:26 / /cgroup/net_cls rw,relatime - cgroup cgroup rw,net_cls 34 21 0:27 / /cgroup/blkio rw,relatime - cgroup cgroup rw,blkio 35 21 0:28 / /var/www rw,relatime - fuse.glusterfs /etc/glusterfs/glusterfs-www.vol rw,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072 36 21 0:29 / /var/upload rw,relatime - fuse.glusterfs /etc/glusterfs/glusterfs-upload.vol rw,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072 37 21 0:30 / /var/lib/nfs/rpc_pipefs rw,relatime - rpc_pipefs sunrpc rw 39 21 0:31 / /data/www rw,relatime - nfs 172.17.39.78:/www rw,vers=3,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,port=38467,timeo=600,retrans=2,sec=sys,mountaddr=172.17.39.78,mountvers=3,mountport=38465,mountproto=tcp,local_lock=none,addr=172.17.39.78 GlusterFS config: cat /etc/glusterfs/glusterfs-www.vol volume remote1 type protocol/client option transport-type tcp option remote-host 172.17.39.71 option ping-timeout 10 option transport.socket.nodelay on # undocumented option for speed # http://gluster.org/pipermail/gluster-users/2009-September/003158.html option remote-subvolume /data/www end-volume volume remote2 type protocol/client option transport-type tcp option remote-host 172.17.39.72 option ping-timeout 10 option transport.socket.nodelay on # undocumented option for speed # http://gluster.org/pipermail/gluster-users/2009-September/003158.html option remote-subvolume /data/www end-volume volume remote3 type protocol/client option transport-type tcp option remote-host 172.17.39.73 option ping-timeout 10 option transport.socket.nodelay on # undocumented option for speed # http://gluster.org/pipermail/gluster-users/2009-September/003158.html option remote-subvolume /data/www end-volume volume remote4 type protocol/client option transport-type tcp option remote-host 172.17.39.74 option ping-timeout 10 option transport.socket.nodelay on # undocumented option for speed # http://gluster.org/pipermail/gluster-users/2009-September/003158.html option remote-subvolume /data/www end-volume volume replicate1 type cluster/replicate option lookup-unhashed off # off will reduce cpu usage, and network option local-volume-name 'hostname' subvolumes remote1 remote2 end-volume volume replicate2 type cluster/replicate option lookup-unhashed off # off will reduce cpu usage, and network option local-volume-name 'hostname' subvolumes remote3 remote4 end-volume volume distribute type cluster/distribute subvolumes replicate1 replicate2 end-volume volume iocache type performance/io-cache option cache-size 8192MB # default is 32MB subvolumes distribute end-volume volume writeback type performance/write-behind option cache-size 1024MB option window-size 1MB subvolumes iocache end-volume ### Add io-threads for parallel requisitions volume iothreads type performance/io-threads option thread-count 64 # default is 16 subvolumes writeback end-volume volume ra type performance/read-ahead option page-size 2MB option page-count 16 option force-atime-update no subvolumes iothreads end-volume

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  • Dealing with external processes

    - by Jesse Aldridge
    I've been working on a gui app that needs to manage external processes. Working with external processes leads to a lot of issues that can make a programmer's life difficult. I feel like maintenence on this app is taking an unacceptably long time. I've been trying to list the things that make working with external processes difficult so that I can come up with ways of mitigating the pain. This kind of turned into a rant which I thought I'd post here in order to get some feedback and to provide some guidance to anybody thinking about sailing into these very murky waters. Here's what I've got so far: Output from the child can get mixed up with output from the parent. This can make both outputs misleading and hard to read. It can be hard to tell what came from where. It becomes harder to figure out what's going on when things are asynchronous. Here's a contrived example: import textwrap, os, time from subprocess import Popen test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) proc = Popen('python -B "%s"' % test_path) for i in range(3): print 'Hello %i' % i time.sleep(1) os.remove(test_path) I guess I could have the child process write its output to a file. But it can be annoying to have to open up a file every time I want to see the result of a print statement. If I have code for the child process I could add a label, something like print 'child: Hello %i', but it can be annoying to do that for every print. And it adds some noise to the output. And of course I can't do it if I don't have access to the code. I could manually manage the process output. But then you open up a huge can of worms with threads and polling and stuff like that. A simple solution is to treat processes like synchronous functions, that is, no further code executes until the process completes. In other words, make the process block. But that doesn't work if you're building a gui app. Which brings me to the next problem... Blocking processes cause the gui to become unresponsive. import textwrap, sys, os from subprocess import Popen from PyQt4.QtGui import * from PyQt4.QtCore import * test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) app = QApplication(sys.argv) button = QPushButton('Launch process') def launch_proc(): # Can't move the window until process completes proc = Popen('python -B "%s"' % test_path) proc.communicate() button.connect(button, SIGNAL('clicked()'), launch_proc) button.show() app.exec_() os.remove(test_path) Qt provides a process wrapper of its own called QProcess which can help with this. You can connect functions to signals to capture output relatively easily. This is what I'm currently using. But I'm finding that all these signals behave suspiciously like goto statements and can lead to spaghetti code. I think I want to get sort-of blocking behavior by having the 'finished' signal from QProcess call a function containing all the code that comes after the process call. I think that should work but I'm still a bit fuzzy on the details... Stack traces get interrupted when you go from the child process back to the parent process. If a normal function screws up, you get a nice complete stack trace with filenames and line numbers. If a subprocess screws up, you'll be lucky if you get any output at all. You end up having to do a lot more detective work everytime something goes wrong. Speaking of which, output has a way of disappearing when dealing external processes. Like if you run something via the windows 'cmd' command, the console will pop up, execute the code, and then disappear before you have a chance to see the output. You have to pass the /k flag to make it stick around. Similar issues seem to crop up all the time. I suppose both problems 3 and 4 have the same root cause: no exception handling. Exception handling is meant to be used with functions, it doesn't work with processes. Maybe there's some way to get something like exception handling for processes? I guess that's what stderr is for? But dealing with two different streams can be annoying in itself. Maybe I should look into this more... Processes can hang and stick around in the background without you realizing it. So you end up yelling at your computer cuz it's going so slow until you finally bring up your task manager and see 30 instances of the same process hanging out in the background. Also, hanging background processes can interefere with other instances of the process in various fun ways, such as causing permissions errors by holding a handle to a file or someting like that. It seems like an easy solution to this would be to have the parent process kill the child process on exit if the child process didn't close itself. But if the parent process crashes, cleanup code might not get called and the child can be left hanging. Also, if the parent waits for the child to complete, and the child is in an infinite loop or something, you can end up with two hanging processes. This problem can tie in to problem 2 for extra fun, causing your gui to stop responding entirely and force you to kill everything with the task manager. F***ing quotes Parameters often need to be passed to processes. This is a headache in itself. Especially if you're dealing with file paths. Say... 'C:/My Documents/whatever/'. If you don't have quotes, the string will often be split at the space and interpreted as two arguments. If you need nested quotes you can use ' and ". But if you need to use more than two layers of quotes, you have to do some nasty escaping, for example: "cmd /k 'python \'path 1\' \'path 2\''". A good solution to this problem is passing parameters as a list rather than as a single string. Subprocess allows you to do this. Can't easily return data from a subprocess. You can use stdout of course. But what if you want to throw a print in there for debugging purposes? That's gonna screw up the parent if it's expecting output formatted a certain way. In functions you can print one string and return another and everything works just fine. Obscure command-line flags and a crappy terminal based help system. These are problems I often run into when using os level apps. Like the /k flag I mentioned, for holding a cmd window open, who's idea was that? Unix apps don't tend to be much friendlier in this regard. Hopefully you can use google or StackOverflow to find the answer you need. But if not, you've got a lot of boring reading and frusterating trial and error to do. External factors. This one's kind of fuzzy. But when you leave the relatively sheltered harbor of your own scripts to deal with external processes you find yourself having to deal with the "outside world" to a much greater extent. And that's a scary place. All sorts of things can go wrong. Just to give a random example: the cwd in which a process is run can modify it's behavior. There are probably other issues, but those are the ones I've written down so far. Any other snags you'd like to add? Any suggestions for dealing with these problems?

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  • How to find an entry-level job after you already have a graduate degree?

    - by Uri
    Note: I asked this question in early 2009. A couple of months later, I found a great job. I've previously updated this question with some tips for whoever ends up in a similar situation, and now cleaned it up a little for the benefit of the fresh batch of graduates. Original post: In my early 20s I abandoned a great C++ development career path in a major company to go to graduate school and get a research masters (3 years). I did another year in industrial research, and then moved to the US to attend graduate school again, getting another masters and a Ph.D in software engineering from a top school (another 6 years down the drain). I was coding the whole way throughout my degrees (core Java and Eclipse plug-ins) and working on research related to software engineering (usability of APIs). I ended up graduating the year of the recession, with a son on the way and the prospects of no healthcare. Academic jobs and industrial research jobs are quite scarce. Initially, I was naive, thinking that with my background, I could easily find a coding job. Big mistake. It turns out that I'm in a complicated position. Entry level positions are usually offered to college undergraduates. I attended my school's career fairs, but you could immediately see signs of Ph.D. aversion and overqualification issues. Some of the recruiters I spoke with explicitly told me that they wanted 20 year olds with clean slates, and some were looking for interns since they are in various forms of hiring freezes. I managed to get a couple of interviews from these career fairs and through recruiters. However, since I've been out of school for a long time and programming primarily in Java, I am also no longer proficient in C/C++ and the usual range of college-level interview questions that everyone uses. I had no problems with this when I was 19 and interviewing for my first job since a lot of what you do in C is manipulate pointers and I was coding C++ for fun and for school. Later I was routinely doing pointer manipulation on the job, and during my first masters taught college courses with data structures and C++. But even though I remember many properties of C++ well, it's been close to ten years since I regularly used C++ and pointers. As a Java developer I rarely had to work at this level, but experience in OOD and in writing good maintainable code is meaningless for C++ interviews. Reading books as a refresh and looking at sample code did not do the trick. I also looked at mid-to-senior level Java positions, but most of them focused on J2EE APIs rather than on core Java and required a certain number of years in industrial positions. Coding research tools and prior C++ experience doesn't count. So that sends me back to entry-level jobs that are posted through job-boards, and these are not common (mostly they are Monster junk), and small companies are even less likely to answer a Ph.D. compared to the giants who participate in top-10 career fairs. Even worse, in many companies initial screening is done by HR folks who really don't want to deal with anything anomalous like a Ph.D. Any tips on how I should approach this intractable position? For example, what should I write in cover letters? Note that while immigration is not an issue for me, I cannot go freelance as I need the benefits (and in particular group health insurance). During my studies I had no time to contribute to open-source projects or maintain a popular blog, so even if I invested in that now there would be no immediate benefit. Updates: In the two months after posting this I received several offers to work as a core Java developer in the financial industry and accepted one from a firm where I am working to this day. For those who find themselves in similar situations, here are my tips: Give up on trying to find an entry level positions. You can't undo time. Accept the fact that there is Ph.D. discrimination in the job market (some might say rightfully so). It is legal to discriminate based on education. No point fighting it. The most important tip is to focus on the language you are comfortable with. The sad truth about programming in a particular language is that it is not like riding a bike. If you haven't used a language in the last few years, and can't actually apply it routinely (not just as a refresher) before you start your search, it is going to be very difficult to do well in an interview. Now that I'm interviewing others, I routinely see it in folks with a mixed C++/Java background. We maintain "a shadow" of the old language but end up with a weird mix that makes it hard to interview on either. Entry-level folks are at an advantage here since they usually have one language. Memory can help you do great in a screening interview, but without recent day-to-day experience, code tests will be difficult. Despite the supposed relation, core Java programming and J2EE programming are two different things with different skillsets. If you come from academia, you likely have very little J2EE experience and may find it hard to get accepted for a J2EE job. J2EE jobs seem to have a larger list of acronyms in their requirements. In addition, from interviewing J2EE developers it seems that for many there is a focus on mastering specific APIs and architectures, whereas core Java development tends to be secondary. In the same way that I can no longer manipulate pointers well, a J2EE developer may have difficulties doing low level Java manipulation. This puts you at a relative advantage in competing for core Java jobs! If you are able to work for startups (in terms of family life and stability) or migrate to startup-rich areas such as the west coast, you can find many exciting opportunities where advanced degrees are a benefit. I've since been approached by several startups, although I had to decline. Work through a recruiter if possible. They have direct contacts with the hiring parties, allowing you to "stand out". It is better to get a clear yes/no confirmation from a recruiter on whether a company might be interested in interviewing you, than it is to send your resume and hope that someone will ever see it. Recruiters are also a great way of bypassing HR. However, also beware of recruiters. They have a vested interest and will go to various shady practices and pressure tactics. To find a good recruiter, talk to a friend who declined a job offer he got through a recruiter. A good recruiter, to me, is measured in how they handle that. Interview for the jobs that require your core strength. If you're rusty or entirely unfamiliar with a technology around which the job revolves, you're probably not a good match. Yes, you probably have the talent to master them, but most companies would want "instant gratification". I got my offers from companies that wanted core Java developer. I didn't do well on places that wanted advance C++ because I am too rusty and not up to date on recent libraries. I also didn't hear from companies that wanted lots of J2EE experience, and that's ok. Finding companies that want core Java without web is harder, but exists in specific industries (e.g., finance, defense). This requires a lot more legwork in terms of search, but these jobs do exist. There are different interview styles. Some companies focus on puzzles, some companies focus on algorithms, and some companies focus on design and coding skills. I had the most success in places where the questions were the most related to the function I would have been performing. Pick companies accordingly as well.

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  • Drupal Ctools Form Wizard in a Block

    - by Iamjon
    Hi everyone I created a custom module that has a Ctools multi step form. It's basically a copy of http://www.nicklewis.org/using-chaos-tools-form-wizard-build-multistep-forms-drupal-6. The form works. I can see it if I got to the url i made for it. For the life of me I can't get the multistep form to show up in a block. Any clues? /** * Implementation of hook_block() * */ function mycrazymodule_block($op='list', $delta=0, $edit=array()) { switch ($op) { case 'list': $blocks[0]['info'] = t('SFT Getting Started'); $blocks[1]['info'] = t('SFT Contact US'); $blocks[2]['info'] = t('SFT News Letter'); return $blocks; case 'view': switch ($delta){ case '0': $block['subject'] = t('SFT Getting Started Subject'); $block['content'] = mycrazymodule_wizard(); break; case '1': $block['subject'] = t('SFT Contact US Subject'); $block['content'] = t('SFT Contact US content'); break; case '2': $block['subject'] = t('SFT News Letter Subject'); $block['content'] = t('SFT News Letter cONTENT'); break; } return $block; } } /** * Implementation of hook_menu(). */ function mycrazymodule_menu() { $items['hellocowboy'] = array( 'title' = 'Two Step Form', 'page callback' = 'mycrazymodule_wizard', 'access arguments' = array('access content') ); return $items; } /** * menu callback for the multistep form * step is whatever arg one is -- and will refer to the keys listed in * $form_info['order'], and $form_info['forms'] arrays */ function mycrazymodule_wizard() { $step = arg(1); // required includes for wizard $form_state = array(); ctools_include('wizard'); ctools_include('object-cache'); // The array that will hold the two forms and their options $form_info = array( 'id' = 'getting_started', 'path' = "hellocowboy/%step", 'show trail' = FALSE, 'show back' = FALSE, 'show cancel' = false, 'show return' =false, 'next text' = 'Submit', 'next callback' = 'getting_started_add_subtask_next', 'finish callback' = 'getting_started_add_subtask_finish', 'return callback' = 'getting_started_add_subtask_finish', 'order' = array( 'basic' = t('Step 1: Basic Info'), 'lecture' = t('Step 2: Choose Lecture'), ), 'forms' = array( 'basic' = array( 'form id' = 'basic_info_form' ), 'lecture' = array( 'form id' = 'choose_lecture_form' ), ), ); $form_state = array( 'cache name' = NULL, ); // no matter the step, you will load your values from the callback page $getstart = getting_started_get_page_cache(NULL); if (!$getstart) { // set form to first step -- we have no data $step = current(array_keys($form_info['order'])); $getstart = new stdClass(); //create cache ctools_object_cache_set('getting_started', $form_state['cache name'], $getstart); //print_r($getstart); } //THIS IS WHERE WILL STORE ALL FORM DATA $form_state['getting_started_obj'] = $getstart; // and this is the witchcraft that makes it work $output = ctools_wizard_multistep_form($form_info, $step, $form_state); return $output; } function basic_info_form(&$form, &$form_state){ $getstart = &$form_state['getting_started_obj']; $form['firstname'] = array( '#weight' = '0', '#type' = 'textfield', '#title' = t('firstname'), '#size' = 60, '#maxlength' = 255, '#required' = TRUE, ); $form['lastname'] = array( '#weight' = '1', '#type' = 'textfield', '#title' = t('lastname'), '#required' = TRUE, '#size' = 60, '#maxlength' = 255, ); $form['phone'] = array( '#weight' = '2', '#type' = 'textfield', '#title' = t('phone'), '#required' = TRUE, '#size' = 60, '#maxlength' = 255, ); $form['email'] = array( '#weight' = '3', '#type' = 'textfield', '#title' = t('email'), '#required' = TRUE, '#size' = 60, '#maxlength' = 255, ); $form['newsletter'] = array( '#weight' = '4', '#type' = 'checkbox', '#title' = t('I would like to receive the newsletter'), '#required' = TRUE, '#return_value' = 1, '#default_value' = 1, ); $form_state['no buttons'] = TRUE; } function basic_info_form_validate(&$form, &$form_state){ $email = $form_state['values']['email']; $phone = $form_state['values']['phone']; if(valid_email_address($email) != TRUE){ form_set_error('Dude you have an error', t('Where is your email?')); } //if (strlen($phone) 0 && !ereg('^[0-9]{1,3}-[0-9]{3}-[0-9]{3,4}-[0-9]{3,4}$', $phone)) { //form_set_error('Dude the phone', t('Phone number must be in format xxx-xxx-nnnn-nnnn.')); //} } function basic_info_form_submit(&$form, &$form_state){ //Grab the variables $firstname =check_plain ($form_state['values']['firstname']); $lastname = check_plain ($form_state['values']['lastname']); $email = check_plain ($form_state['values']['email']); $phone = check_plain ($form_state['values']['phone']); $newsletter = $form_state['values']['newsletter']; //Send the form and Grab the lead id $leadid = send_first_form($lastname, $firstname, $email,$phone, $newsletter); //Put into form $form_state['getting_started_obj']-firstname = $firstname; $form_state['getting_started_obj']-lastname = $lastname; $form_state['getting_started_obj']-email = $email; $form_state['getting_started_obj']-phone = $phone; $form_state['getting_started_obj']-newsletter = $newsletter; $form_state['getting_started_obj']-leadid = $leadid; } function choose_lecture_form(&$form, &$form_state){ $one = 'event 1' $two = 'event 2' $three = 'event 3' $getstart = &$form_state['getting_started_obj']; $form['lecture'] = array( '#weight' = '5', '#default_value' = 'two', '#options' = array( 'one' = $one, 'two' = $two, 'three' = $three, ), '#type' = 'radios', '#title' = t('Select Workshop'), '#required' = TRUE, ); $form['attendees'] = array( '#weight' = '6', '#default_value' = 'one', '#options' = array( 'one' = t('I will be arriving alone'), 'two' =t('I will be arriving with a guest'), ), '#type' = 'radios', '#title' = t('Attendees'), '#required' = TRUE, ); $form_state['no buttons'] = TRUE; } /** * Same idea as previous steps submit * */ function choose_lecture_form_submit(&$form, &$form_state) { $workshop = $form_state['values']['lecture']; $leadid = $form_state['getting_started_obj']-leadid; $attendees = $form_state['values']['attendees']; $form_state['getting_started_obj']-lecture = $workshop; $form_state['getting_started_obj']-attendees = $attendees; send_second_form($workshop, $attendees, $leadid); } /*----PART 3 CTOOLS CALLBACKS -- these usually don't have to be very unique ---------------------- */ /** * Callback generated when the add page process is finished. * this is where you'd normally save. */ function getting_started_add_subtask_finish(&$form_state) { dpm($form_state); $getstart = &$form_state['getting_started_obj']; drupal_set_message('mycrazymodule '.$getstart-name.' successfully deployed' ); //Get id // Clear the cache ctools_object_cache_clear('getting_started', $form_state['cache name']); $form_state['redirect'] = 'hellocowboy'; } /** * Callback for the proceed step * */ function getting_started_add_subtask_next(&$form_state) { dpm($form_state); $getstart = &$form_state['getting_started_obj']; $cache = ctools_object_cache_set('getting_started', $form_state['cache name'], $getstart); } /*----PART 4 CTOOLS FORM STORAGE HANDLERS -- these usually don't have to be very unique ---------------------- */ /** * Remove an item from the object cache. */ function getting_started_clear_page_cache($name) { ctools_object_cache_clear('getting_started', $name); } /** * Get the cached changes to a given task handler. */ function getting_started_get_page_cache($name) { $cache = ctools_object_cache_get('getting_started', $name); return $cache; } //Salesforce Functions function send_first_form($lastname, $firstname,$email,$phone, $newsletter){ $send = array("LastName" = $lastname , "FirstName" = $firstname, "Email" = $email ,"Phone" = $phone , "Newsletter__c" =$newsletter ); $sf = salesforce_api_connect(); $response = $sf-client-create(array($send), 'Lead'); dpm($response); return $response-id; } function send_second_form($workshop, $attendees, $leadid){ $send = array("Id" = $leadid , "Number_Of_Pepole__c" = "2" ); $sf = salesforce_api_connect(); $response = $sf-client-update(array($send), 'Lead'); dpm($response, 'the final response'); return $response-id; }

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  • Can't figure out where race condition is occuring

    - by Nik
    I'm using Valgrind --tool=drd to check my application that uses Boost::thread. Basically, the application populates a set of "Book" values with "Kehai" values based on inputs through a socket connection. On a seperate thread, a user can connect and get the books send to them. Its fairly simple, so i figured using a boost::mutex::scoped_lock on the location that serializes the book and the location that clears out the book data should be suffice to prevent any race conditions. Here is the code: void Book::clear() { boost::mutex::scoped_lock lock(dataMutex); for(int i =NUM_KEHAI-1; i >= 0; --i) { bid[i].clear(); ask[i].clear(); } } int Book::copyChangedKehaiToString(char* dst) const { boost::mutex::scoped_lock lock(dataMutex); sprintf(dst, "%-4s%-13s",market.c_str(),meigara.c_str()); int loc = 17; for(int i = 0; i < Book::NUM_KEHAI; ++i) { if(ask[i].changed > 0) { sprintf(dst+loc,"A%i%-21s%-21s%-21s%-8s%-4s",i,ask[i].price.c_str(),ask[i].volume.c_str(),ask[i].number.c_str(),ask[i].postTime.c_str(),ask[i].status.c_str()); loc += 77; } } for(int i = 0; i < Book::NUM_KEHAI; ++i) { if(bid[i].changed > 0) { sprintf(dst+loc,"B%i%-21s%-21s%-21s%-8s%-4s",i,bid[i].price.c_str(),bid[i].volume.c_str(),bid[i].number.c_str(),bid[i].postTime.c_str(),bid[i].status.c_str()); loc += 77; } } return loc; } The clear() function and the copyChangedKehaiToString() function are called in the datagetting thread and data sending thread,respectively. Also, as a note, the class Book: struct Book { private: Book(const Book&); Book& operator=(const Book&); public: static const int NUM_KEHAI=10; struct Kehai; friend struct Book::Kehai; struct Kehai { private: Kehai& operator=(const Kehai&); public: std::string price; std::string volume; std::string number; std::string postTime; std::string status; int changed; Kehai(); void copyFrom(const Kehai& other); Kehai(const Kehai& other); inline void clear() { price.assign(""); volume.assign(""); number.assign(""); postTime.assign(""); status.assign(""); changed = -1; } }; std::vector<Kehai> bid; std::vector<Kehai> ask; tm recTime; mutable boost::mutex dataMutex; Book(); void clear(); int copyChangedKehaiToString(char * dst) const; }; When using valgrind --tool=drd, i get race condition errors such as the one below: ==26330== Conflicting store by thread 1 at 0x0658fbb0 size 4 ==26330== at 0x653AE68: std::string::_M_mutate(unsigned int, unsigned int, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x653AFC9: std::string::_M_replace_safe(unsigned int, unsigned int, char const*, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x653B064: std::string::assign(char const*, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x653B134: std::string::assign(char const*) (in /usr/lib/libstdc++.so.6.0.8) ==26330== by 0x8055D64: Book::Kehai::clear() (Book.h:50) ==26330== by 0x8094A29: Book::clear() (Book.cpp:78) ==26330== by 0x808537E: RealKernel::start() (RealKernel.cpp:86) ==26330== by 0x804D15A: main (main.cpp:164) ==26330== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.8 ==26330== Other segment start (thread 2) ==26330== at 0x400BB59: pthread_mutex_unlock (drd_pthread_intercepts.c:633) ==26330== by 0xC59565: pthread_mutex_unlock (in /lib/libc-2.5.so) ==26330== by 0x805477C: boost::mutex::unlock() (mutex.hpp:56) ==26330== by 0x80547C9: boost::unique_lock<boost::mutex>::~unique_lock() (locks.hpp:340) ==26330== by 0x80949BA: Book::copyChangedKehaiToString(char*) const (Book.cpp:134) ==26330== by 0x80937EE: BookSerializer::serializeBook(Book const&, std::string const&) (BookSerializer.cpp:41) ==26330== by 0x8092D05: BookSnapshotManager::getSnaphotDataList() (BookSnapshotManager.cpp:72) ==26330== by 0x8088179: SnapshotServer::getDataList() (SnapshotServer.cpp:246) ==26330== by 0x808870F: SnapshotServer::run() (SnapshotServer.cpp:183) ==26330== by 0x808BAF5: boost::_mfi::mf0<void, RealThread>::operator()(RealThread*) const (mem_fn_template.hpp:49) ==26330== by 0x808BB4D: void boost::_bi::list1<boost::_bi::value<RealThread*> >::operator()<boost::_mfi::mf0<void, RealThread>, boost::_bi::list0>(boost::_bi::type<void>, boost::_mfi::mf0<void, RealThread>&, boost::_bi::list0&, int) (bind.hpp:253) ==26330== by 0x808BB90: boost::_bi::bind_t<void, boost::_mfi::mf0<void, RealThread>, boost::_bi::list1<boost::_bi::value<RealThread*> > >::operator()() (bind_template.hpp:20) ==26330== Other segment end (thread 2) ==26330== at 0x400B62A: pthread_mutex_lock (drd_pthread_intercepts.c:580) ==26330== by 0xC59535: pthread_mutex_lock (in /lib/libc-2.5.so) ==26330== by 0x80546B8: boost::mutex::lock() (mutex.hpp:51) ==26330== by 0x805473B: boost::unique_lock<boost::mutex>::lock() (locks.hpp:349) ==26330== by 0x8054769: boost::unique_lock<boost::mutex>::unique_lock(boost::mutex&) (locks.hpp:227) ==26330== by 0x8094711: Book::copyChangedKehaiToString(char*) const (Book.cpp:113) ==26330== by 0x80937EE: BookSerializer::serializeBook(Book const&, std::string const&) (BookSerializer.cpp:41) ==26330== by 0x808870F: SnapshotServer::run() (SnapshotServer.cpp:183) ==26330== by 0x808BAF5: boost::_mfi::mf0<void, RealThread>::operator()(RealThread*) const (mem_fn_template.hpp:49) ==26330== by 0x808BB4D: void boost::_bi::list1<boost::_bi::value<RealThread*> >::operator()<boost::_mfi::mf0<void, RealThread>, boost::_bi::list0>(boost::_bi::type<void>, boost::_mfi::mf0<void, RealThread>&, boost::_bi::list0&, int) (bind.hpp:253) For the life of me, i can't figure out where the race condition is. As far as I can tell, clearing the kehai is done only after having taken the mutex, and the same holds true with copying it to a string. Does anyone have any ideas what could be causing this, or where I should look? Thank you kindly.

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  • C socket programming: select() is returning 0 despite messages sent from server

    - by Fantastic Fourier
    Hey all, I'm using select() to recv() messages from server, using TCP/IP. When I send() messages from the server, it returns a reasonable number of bytes, saying it's sent successful. And it does get to the client successfully when I use while loop to just recv(). Everything is fine and dandy. while(1) recv() // obviously pseudocode However, when I try to use select(), select() returns 0 from timeout (which is set to 1 second) and for the life of me I cannot figure out why it doesn't see the messages sent from the server. I should also mention that when the server disconnects, select() doesn't see that either, where as if I were to use recv(), it would return 0 to indicate that the connection using the socket has been closed. Any inputs or thoughts are deeply appreciated. #include <arpa/inet.h> #include <errno.h> #include <fcntl.h> #include <netdb.h> #include <netinet/in.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <sys/select.h> #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <time.h> #include <unistd.h> #define SERVER_PORT 10000 #define MAX_CONNECTION 20 #define MAX_MSG 50 struct client { char c_name[MAX_MSG]; char g_name[MAX_MSG]; int csock; int host; // 0 = not host of a multicast group struct sockaddr_in client_address; struct client * next_host; struct client * next_client; }; struct fd_info { char c_name[MAX_MSG]; int socks_inuse[MAX_CONNECTION]; int sock_fd, max_fd; int exit; struct client * c_sys; struct sockaddr_in c_address[MAX_CONNECTION]; struct sockaddr_in server_address; struct sockaddr_in client_address; fd_set read_set; }; struct message { char c_name[MAX_MSG]; char g_name[MAX_MSG]; char _command[3][MAX_MSG]; char _payload[MAX_MSG]; struct sockaddr_in client_address; struct client peer; }; int main(int argc, char * argv[]) { char * host; char * temp; int i, sockfd; int msg_len, rv, ready; int connection, management, socketread; int sockfds[MAX_CONNECTION]; // for three threads that handle new connections, user inputs and select() for sockets pthread_t connection_handler, manager, socket_reader; struct sockaddr_in server_address, client_address; struct hostent * hserver, cserver; struct timeval timeout; struct message msg; struct fd_info info; info.exit = 0; // exit information: if exit = 1, threads quit info.c_sys = NULL; // looking up from the host database if (argc == 3) { host = argv[1]; // server address strncpy(info.c_name, argv[2], strlen(argv[2])); // client name } else { printf("plz read the manual, kthxbai\n"); exit(1); } printf("host is %s and hp is %p\n", host, hserver); hserver = gethostbyname(host); if (hserver) { printf("host found: %s\n", hserver->h_name ); } else { printf("host not found\n"); exit(1); } // setting up address and port structure information on serverside bzero((char * ) &server_address, sizeof(server_address)); // copy zeroes into string server_address.sin_family = AF_INET; memcpy(&server_address.sin_addr, hserver->h_addr, hserver->h_length); server_address.sin_port = htons(SERVER_PORT); bzero((char * ) &client_address, sizeof(client_address)); // copy zeroes into string client_address.sin_family = AF_INET; client_address.sin_addr.s_addr = htonl(INADDR_ANY); client_address.sin_port = htons(SERVER_PORT); // opening up socket sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) exit(1); else { printf("socket is opened: %i \n", sockfd); info.sock_fd = sockfd; } // sets up time out option for the bound socket timeout.tv_sec = 1; // seconds timeout.tv_usec = 0; // micro seconds ( 0.5 seconds) setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timeval)); // binding socket to a port rv = bind(sockfd, (struct sockaddr *) &client_address, sizeof(client_address)); if (rv < 0) { printf("MAIN: ERROR bind() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("socket is bound\n"); printf("MAIN: %li \n", client_address.sin_addr.s_addr); // connecting rv = connect(sockfd, (struct sockaddr *) &server_address, sizeof(server_address)); info.server_address = server_address; info.client_address = client_address; info.sock_fd = sockfd; info.max_fd = sockfd; printf("rv = %i\n", rv); if (rv < 0) { printf("MAIN: ERROR connect() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("connected\n"); fd_set readset; FD_ZERO(&readset); FD_ZERO(&info.read_set); FD_SET(info.sock_fd, &info.read_set); while(1) { readset = info.read_set; printf("MAIN: %i \n", readset); ready = select((info.max_fd)+1, &readset, NULL, NULL, &timeout); if(ready == -1) { sleep(2); printf("TEST: MAIN: ready = -1. %s \n", strerror(errno)); } else if (ready == 0) { sleep(2); printf("TEST: MAIN: ready = 0. %s \n", strerror(errno)); } else if (ready > 0) { printf("TEST: MAIN: ready = %i. %s at socket %i \n", ready, strerror(errno), i); for(i = 0; i < ((info.max_fd)+1); i++) { if(FD_ISSET(i, &readset)) { rv = recv(sockfd, &msg, 500, 0); if(rv < 0) continue; else if(rv > 0) printf("MAIN: TEST: %s %s \n", msg._command[0], msg._payload); else if (rv == 0) { sleep(3); printf("MAIN: TEST: SOCKET CLOSEDDDDDD \n"); } FD_CLR(i, &readset); } } } info.read_set = readset; } // close connection close(sockfd); printf("socket closed. BYE! \n"); return(0); }

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  • Error with my Android Application httpGet

    - by Coombes
    Basically I'm getting a strange issue with my Android application, it's supposed to grab a JSON Array and print out some values, the class looks like this: ShowComedianActivity.class package com.example.connecttest; public class ShowComedianActivity extends Activity{ TextView name; TextView add; TextView email; TextView tel; String id; // Progress Dialog private ProgressDialog pDialog; //JSON Parser class JSONParser jsonParser = new JSONParser(); // Single Comedian url private static final String url_comedian_details = "http://86.9.71.17/connect/get_comedian_details.php"; // JSON Node names private static final String TAG_SUCCESS = "success"; private static final String TAG_COMEDIAN = "comedian"; private static final String TAG_ID = "id"; private static final String TAG_NAME = "name"; private static final String TAG_ADDRESS = "address"; private static final String TAG_EMAIL = "email"; private static final String TAG_TEL = "tel"; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.show_comedian); // Getting Comedian Details from intent Intent i = getIntent(); // Getting id from intent id = i.getStringExtra(TAG_ID); new GetComedianDetails().execute(); } class GetComedianDetails extends AsyncTask<String, String, String>{ protected void onPreExecute(){ super.onPreExecute(); pDialog = new ProgressDialog(ShowComedianActivity.this); pDialog.setMessage("Fetching Comedian details. Please wait..."); pDialog.setIndeterminate(false); pDialog.setCancelable(true); pDialog.show(); } @Override protected String doInBackground(String... params) { runOnUiThread(new Runnable(){ public void run(){ int success; try{ //Building parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("id",id)); // Getting comedian details via HTTP request // Uses a GET request JSONObject json = jsonParser.makeHttpRequest(url_comedian_details, "GET", params); // Check Log for json response Log.d("Single Comedian details", json.toString()); //JSON Success tag success = json.getInt(TAG_SUCCESS); if(success == 1){ // Succesfully received product details JSONArray comedianObj = json.getJSONArray(TAG_COMEDIAN); //JSON Array // get first comedian object from JSON Array JSONObject comedian = comedianObj.getJSONObject(0); // comedian with id found name = (TextView) findViewById(R.id.name); add = (TextView) findViewById(R.id.add); email = (TextView) findViewById(R.id.email); tel = (TextView) findViewById(R.id.tel); // Set text to details name.setText(comedian.getString(TAG_NAME)); add.setText(comedian.getString(TAG_ADDRESS)); email.setText(comedian.getString(TAG_EMAIL)); tel.setText(comedian.getString(TAG_TEL)); } } catch (JSONException e){ e.printStackTrace(); } } }); return null; } } } And my JSON Parser class looks like: package com.example.connecttest; public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } // function get json from url // by making HTTP POST or GET method public JSONObject makeHttpRequest(String url, String method, List<NameValuePair> params) { // Making HTTP request try { // check for request method if(method == "POST"){ // request method is POST // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); }else if(method == "GET"){ // request method is GET DefaultHttpClient httpClient = new DefaultHttpClient(); String paramString = URLEncodedUtils.format(params, "utf-8"); url += "?" + paramString; HttpGet httpGet = new HttpGet(url); HttpResponse httpResponse = httpClient.execute(httpGet); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } Now when I run a debug it's querying the correct address with ?id=1 on the end of the URL, and when I navigate to that url I get the following JSON Array: {"success":1,"comedian":[{"id":"1","name":"Michael Coombes","address":"5 Trevethenick Road","email":"[email protected]","tel":"xxxxxxxxxxxx"}]} However my app just crashes, the log-cat report looks like this: 03-22 02:05:02.140: E/Trace(3776): error opening trace file: No such file or directory (2) 03-22 02:05:04.590: E/AndroidRuntime(3776): FATAL EXCEPTION: main 03-22 02:05:04.590: E/AndroidRuntime(3776): android.os.NetworkOnMainThreadException 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connect(IoBridge.java:112) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.Socket.connect(Socket.java:842) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.JSONParser.makeHttpRequest(JSONParser.java:62) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.ShowComedianActivity$GetComedianDetails$1.run(ShowComedianActivity.java:89) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.handleCallback(Handler.java:615) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.dispatchMessage(Handler.java:92) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Looper.loop(Looper.java:137) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.app.ActivityThread.main(ActivityThread.java:4745) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invokeNative(Native Method) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invoke(Method.java:511) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 03-22 02:05:04.590: E/AndroidRuntime(3776): at dalvik.system.NativeStart.main(Native Method) From this I'm guessing the error is in the jsonParser.makeHttpRequest however I can't for the life of me figure out what's going wrong and was hoping someone brighter than I could illuminate me.

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  • Building applications with WPF, MVVM and Prism(aka CAG)

    - by skjagini
    In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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  • Introduction to the ASP.NET Web API

    - by Stephen.Walther
    I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html>     Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "\n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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  • Red Gate Coder interviews: Alex Davies

    - by Michael Williamson
    Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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  • Introduction to the ASP.NET Web API

    - by Stephen.Walther
    I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html>     Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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  • A way of doing real-world test-driven development (and some thoughts about it)

    - by Thomas Weller
    Lately, I exchanged some arguments with Derick Bailey about some details of the red-green-refactor cycle of the Test-driven development process. In short, the issue revolved around the fact that it’s not enough to have a test red or green, but it’s also important to have it red or green for the right reasons. While for me, it’s sufficient to initially have a NotImplementedException in place, Derick argues that this is not totally correct (see these two posts: Red/Green/Refactor, For The Right Reasons and Red For The Right Reason: Fail By Assertion, Not By Anything Else). And he’s right. But on the other hand, I had no idea how his insights could have any practical consequence for my own individual interpretation of the red-green-refactor cycle (which is not really red-green-refactor, at least not in its pure sense, see the rest of this article). This made me think deeply for some days now. In the end I found out that the ‘right reason’ changes in my understanding depending on what development phase I’m in. To make this clear (at least I hope it becomes clear…) I started to describe my way of working in some detail, and then something strange happened: The scope of the article slightly shifted from focusing ‘only’ on the ‘right reason’ issue to something more general, which you might describe as something like  'Doing real-world TDD in .NET , with massive use of third-party add-ins’. This is because I feel that there is a more general statement about Test-driven development to make:  It’s high time to speak about the ‘How’ of TDD, not always only the ‘Why’. Much has been said about this, and me myself also contributed to that (see here: TDD is not about testing, it's about how we develop software). But always justifying what you do is very unsatisfying in the long run, it is inherently defensive, and it costs time and effort that could be used for better and more important things. And frankly: I’m somewhat sick and tired of repeating time and again that the test-driven way of software development is highly preferable for many reasons - I don’t want to spent my time exclusively on stating the obvious… So, again, let’s say it clearly: TDD is programming, and programming is TDD. Other ways of programming (code-first, sometimes called cowboy-coding) are exceptional and need justification. – I know that there are many people out there who will disagree with this radical statement, and I also know that it’s not a description of the real world but more of a mission statement or something. But nevertheless I’m absolutely sure that in some years this statement will be nothing but a platitude. Side note: Some parts of this post read as if I were paid by Jetbrains (the manufacturer of the ReSharper add-in – R#), but I swear I’m not. Rather I think that Visual Studio is just not production-complete without it, and I wouldn’t even consider to do professional work without having this add-in installed... The three parts of a software component Before I go into some details, I first should describe my understanding of what belongs to a software component (assembly, type, or method) during the production process (i.e. the coding phase). Roughly, I come up with the three parts shown below:   First, we need to have some initial sort of requirement. This can be a multi-page formal document, a vague idea in some programmer’s brain of what might be needed, or anything in between. In either way, there has to be some sort of requirement, be it explicit or not. – At the C# micro-level, the best way that I found to formulate that is to define interfaces for just about everything, even for internal classes, and to provide them with exhaustive xml comments. The next step then is to re-formulate these requirements in an executable form. This is specific to the respective programming language. - For C#/.NET, the Gallio framework (which includes MbUnit) in conjunction with the ReSharper add-in for Visual Studio is my toolset of choice. The third part then finally is the production code itself. It’s development is entirely driven by the requirements and their executable formulation. This is the delivery, the two other parts are ‘only’ there to make its production possible, to give it a decent quality and reliability, and to significantly reduce related costs down the maintenance timeline. So while the first two parts are not really relevant for the customer, they are very important for the developer. The customer (or in Scrum terms: the Product Owner) is not interested at all in how  the product is developed, he is only interested in the fact that it is developed as cost-effective as possible, and that it meets his functional and non-functional requirements. The rest is solely a matter of the developer’s craftsmanship, and this is what I want to talk about during the remainder of this article… An example To demonstrate my way of doing real-world TDD, I decided to show the development of a (very) simple Calculator component. The example is deliberately trivial and silly, as examples always are. I am totally aware of the fact that real life is never that simple, but I only want to show some development principles here… The requirement As already said above, I start with writing down some words on the initial requirement, and I normally use interfaces for that, even for internal classes - the typical question “intf or not” doesn’t even come to mind. I need them for my usual workflow and using them automatically produces high componentized and testable code anyway. To think about their usage in every single situation would slow down the production process unnecessarily. So this is what I begin with: namespace Calculator {     /// <summary>     /// Defines a very simple calculator component for demo purposes.     /// </summary>     public interface ICalculator     {         /// <summary>         /// Gets the result of the last successful operation.         /// </summary>         /// <value>The last result.</value>         /// <remarks>         /// Will be <see langword="null" /> before the first successful operation.         /// </remarks>         double? LastResult { get; }       } // interface ICalculator   } // namespace Calculator So, I’m not beginning with a test, but with a sort of code declaration - and still I insist on being 100% test-driven. There are three important things here: Starting this way gives me a method signature, which allows to use IntelliSense and AutoCompletion and thus eliminates the danger of typos - one of the most regular, annoying, time-consuming, and therefore expensive sources of error in the development process. In my understanding, the interface definition as a whole is more of a readable requirement document and technical documentation than anything else. So this is at least as much about documentation than about coding. The documentation must completely describe the behavior of the documented element. I normally use an IoC container or some sort of self-written provider-like model in my architecture. In either case, I need my components defined via service interfaces anyway. - I will use the LinFu IoC framework here, for no other reason as that is is very simple to use. The ‘Red’ (pt. 1)   First I create a folder for the project’s third-party libraries and put the LinFu.Core dll there. Then I set up a test project (via a Gallio project template), and add references to the Calculator project and the LinFu dll. Finally I’m ready to write the first test, which will look like the following: namespace Calculator.Test {     [TestFixture]     public class CalculatorTest     {         private readonly ServiceContainer container = new ServiceContainer();           [Test]         public void CalculatorLastResultIsInitiallyNull()         {             ICalculator calculator = container.GetService<ICalculator>();               Assert.IsNull(calculator.LastResult);         }       } // class CalculatorTest   } // namespace Calculator.Test       This is basically the executable formulation of what the interface definition states (part of). Side note: There’s one principle of TDD that is just plain wrong in my eyes: I’m talking about the Red is 'does not compile' thing. How could a compiler error ever be interpreted as a valid test outcome? I never understood that, it just makes no sense to me. (Or, in Derick’s terms: this reason is as wrong as a reason ever could be…) A compiler error tells me: Your code is incorrect, but nothing more.  Instead, the ‘Red’ part of the red-green-refactor cycle has a clearly defined meaning to me: It means that the test works as intended and fails only if its assumptions are not met for some reason. Back to our Calculator. When I execute the above test with R#, the Gallio plugin will give me this output: So this tells me that the test is red for the wrong reason: There’s no implementation that the IoC-container could load, of course. So let’s fix that. With R#, this is very easy: First, create an ICalculator - derived type:        Next, implement the interface members: And finally, move the new class to its own file: So far my ‘work’ was six mouse clicks long, the only thing that’s left to do manually here, is to add the Ioc-specific wiring-declaration and also to make the respective class non-public, which I regularly do to force my components to communicate exclusively via interfaces: This is what my Calculator class looks like as of now: using System; using LinFu.IoC.Configuration;   namespace Calculator {     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         public double? LastResult         {             get             {                 throw new NotImplementedException();             }         }     } } Back to the test fixture, we have to put our IoC container to work: [TestFixture] public class CalculatorTest {     #region Fields       private readonly ServiceContainer container = new ServiceContainer();       #endregion // Fields       #region Setup/TearDown       [FixtureSetUp]     public void FixtureSetUp()     {        container.LoadFrom(AppDomain.CurrentDomain.BaseDirectory, "Calculator.dll");     }       ... Because I have a R# live template defined for the setup/teardown method skeleton as well, the only manual coding here again is the IoC-specific stuff: two lines, not more… The ‘Red’ (pt. 2) Now, the execution of the above test gives the following result: This time, the test outcome tells me that the method under test is called. And this is the point, where Derick and I seem to have somewhat different views on the subject: Of course, the test still is worthless regarding the red/green outcome (or: it’s still red for the wrong reasons, in that it gives a false negative). But as far as I am concerned, I’m not really interested in the test outcome at this point of the red-green-refactor cycle. Rather, I only want to assert that my test actually calls the right method. If that’s the case, I will happily go on to the ‘Green’ part… The ‘Green’ Making the test green is quite trivial. Just make LastResult an automatic property:     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         public double? LastResult { get; private set; }     }         One more round… Now on to something slightly more demanding (cough…). Let’s state that our Calculator exposes an Add() method:         ...   /// <summary>         /// Adds the specified operands.         /// </summary>         /// <param name="operand1">The operand1.</param>         /// <param name="operand2">The operand2.</param>         /// <returns>The result of the additon.</returns>         /// <exception cref="ArgumentException">         /// Argument <paramref name="operand1"/> is &lt; 0.<br/>         /// -- or --<br/>         /// Argument <paramref name="operand2"/> is &lt; 0.         /// </exception>         double Add(double operand1, double operand2);       } // interface ICalculator A remark: I sometimes hear the complaint that xml comment stuff like the above is hard to read. That’s certainly true, but irrelevant to me, because I read xml code comments with the CR_Documentor tool window. And using that, it looks like this:   Apart from that, I’m heavily using xml code comments (see e.g. here for a detailed guide) because there is the possibility of automating help generation with nightly CI builds (using MS Sandcastle and the Sandcastle Help File Builder), and then publishing the results to some intranet location.  This way, a team always has first class, up-to-date technical documentation at hand about the current codebase. (And, also very important for speeding up things and avoiding typos: You have IntelliSense/AutoCompletion and R# support, and the comments are subject to compiler checking…).     Back to our Calculator again: Two more R# – clicks implement the Add() skeleton:         ...           public double Add(double operand1, double operand2)         {             throw new NotImplementedException();         }       } // class Calculator As we have stated in the interface definition (which actually serves as our requirement document!), the operands are not allowed to be negative. So let’s start implementing that. Here’s the test: [Test] [Row(-0.5, 2)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) {     ICalculator calculator = container.GetService<ICalculator>();       Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); } As you can see, I’m using a data-driven unit test method here, mainly for these two reasons: Because I know that I will have to do the same test for the second operand in a few seconds, I save myself from implementing another test method for this purpose. Rather, I only will have to add another Row attribute to the existing one. From the test report below, you can see that the argument values are explicitly printed out. This can be a valuable documentation feature even when everything is green: One can quickly review what values were tested exactly - the complete Gallio HTML-report (as it will be produced by the Continuous Integration runs) shows these values in a quite clear format (see below for an example). Back to our Calculator development again, this is what the test result tells us at the moment: So we’re red again, because there is not yet an implementation… Next we go on and implement the necessary parameter verification to become green again, and then we do the same thing for the second operand. To make a long story short, here’s the test and the method implementation at the end of the second cycle: // in CalculatorTest:   [Test] [Row(-0.5, 2)] [Row(295, -123)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) {     ICalculator calculator = container.GetService<ICalculator>();       Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); }   // in Calculator: public double Add(double operand1, double operand2) {     if (operand1 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand1");     }     if (operand2 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand2");     }     throw new NotImplementedException(); } So far, we have sheltered our method from unwanted input, and now we can safely operate on the parameters without further caring about their validity (this is my interpretation of the Fail Fast principle, which is regarded here in more detail). Now we can think about the method’s successful outcomes. First let’s write another test for that: [Test] [Row(1, 1, 2)] public void TestAdd(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Add(operand1, operand2);       Assert.AreEqual(expectedResult, result); } Again, I’m regularly using row based test methods for these kinds of unit tests. The above shown pattern proved to be extremely helpful for my development work, I call it the Defined-Input/Expected-Output test idiom: You define your input arguments together with the expected method result. There are two major benefits from that way of testing: In the course of refining a method, it’s very likely to come up with additional test cases. In our case, we might add tests for some edge cases like ‘one of the operands is zero’ or ‘the sum of the two operands causes an overflow’, or maybe there’s an external test protocol that has to be fulfilled (e.g. an ISO norm for medical software), and this results in the need of testing against additional values. In all these scenarios we only have to add another Row attribute to the test. Remember that the argument values are written to the test report, so as a side-effect this produces valuable documentation. (This can become especially important if the fulfillment of some sort of external requirements has to be proven). So your test method might look something like that in the end: [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 2)] [Row(0, 999999999, 999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, double.MaxValue)] [Row(4, double.MaxValue - 2.5, double.MaxValue)] public void TestAdd(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Add(operand1, operand2);       Assert.AreEqual(expectedResult, result); } And this will produce the following HTML report (with Gallio):   Not bad for the amount of work we invested in it, huh? - There might be scenarios where reports like that can be useful for demonstration purposes during a Scrum sprint review… The last requirement to fulfill is that the LastResult property is expected to store the result of the last operation. I don’t show this here, it’s trivial enough and brings nothing new… And finally: Refactor (for the right reasons) To demonstrate my way of going through the refactoring portion of the red-green-refactor cycle, I added another method to our Calculator component, namely Subtract(). Here’s the code (tests and production): // CalculatorTest.cs:   [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtract(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Subtract(operand1, operand2);       Assert.AreEqual(expectedResult, result); }   [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtractGivesExpectedLastResult(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       calculator.Subtract(operand1, operand2);       Assert.AreEqual(expectedResult, calculator.LastResult); }   ...   // ICalculator.cs: /// <summary> /// Subtracts the specified operands. /// </summary> /// <param name="operand1">The operand1.</param> /// <param name="operand2">The operand2.</param> /// <returns>The result of the subtraction.</returns> /// <exception cref="ArgumentException"> /// Argument <paramref name="operand1"/> is &lt; 0.<br/> /// -- or --<br/> /// Argument <paramref name="operand2"/> is &lt; 0. /// </exception> double Subtract(double operand1, double operand2);   ...   // Calculator.cs:   public double Subtract(double operand1, double operand2) {     if (operand1 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand1");     }       if (operand2 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand2");     }       return (this.LastResult = operand1 - operand2).Value; }   Obviously, the argument validation stuff that was produced during the red-green part of our cycle duplicates the code from the previous Add() method. So, to avoid code duplication and minimize the number of code lines of the production code, we do an Extract Method refactoring. One more time, this is only a matter of a few mouse clicks (and giving the new method a name) with R#: Having done that, our production code finally looks like that: using System; using LinFu.IoC.Configuration;   namespace Calculator {     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         #region ICalculator           public double? LastResult { get; private set; }           public double Add(double operand1, double operand2)         {             ThrowIfOneOperandIsInvalid(operand1, operand2);               return (this.LastResult = operand1 + operand2).Value;         }           public double Subtract(double operand1, double operand2)         {             ThrowIfOneOperandIsInvalid(operand1, operand2);               return (this.LastResult = operand1 - operand2).Value;         }           #endregion // ICalculator           #region Implementation (Helper)           private static void ThrowIfOneOperandIsInvalid(double operand1, double operand2)         {             if (operand1 < 0.0)             {                 throw new ArgumentException("Value must not be negative.", "operand1");             }               if (operand2 < 0.0)             {                 throw new ArgumentException("Value must not be negative.", "operand2");             }         }           #endregion // Implementation (Helper)       } // class Calculator   } // namespace Calculator But is the above worth the effort at all? It’s obviously trivial and not very impressive. All our tests were green (for the right reasons), and refactoring the code did not change anything. It’s not immediately clear how this refactoring work adds value to the project. Derick puts it like this: STOP! Hold on a second… before you go any further and before you even think about refactoring what you just wrote to make your test pass, you need to understand something: if your done with your requirements after making the test green, you are not required to refactor the code. I know… I’m speaking heresy, here. Toss me to the wolves, I’ve gone over to the dark side! Seriously, though… if your test is passing for the right reasons, and you do not need to write any test or any more code for you class at this point, what value does refactoring add? Derick immediately answers his own question: So why should you follow the refactor portion of red/green/refactor? When you have added code that makes the system less readable, less understandable, less expressive of the domain or concern’s intentions, less architecturally sound, less DRY, etc, then you should refactor it. I couldn’t state it more precise. From my personal perspective, I’d add the following: You have to keep in mind that real-world software systems are usually quite large and there are dozens or even hundreds of occasions where micro-refactorings like the above can be applied. It’s the sum of them all that counts. And to have a good overall quality of the system (e.g. in terms of the Code Duplication Percentage metric) you have to be pedantic on the individual, seemingly trivial cases. My job regularly requires the reading and understanding of ‘foreign’ code. So code quality/readability really makes a HUGE difference for me – sometimes it can be even the difference between project success and failure… Conclusions The above described development process emerged over the years, and there were mainly two things that guided its evolution (you might call it eternal principles, personal beliefs, or anything in between): Test-driven development is the normal, natural way of writing software, code-first is exceptional. So ‘doing TDD or not’ is not a question. And good, stable code can only reliably be produced by doing TDD (yes, I know: many will strongly disagree here again, but I’ve never seen high-quality code – and high-quality code is code that stood the test of time and causes low maintenance costs – that was produced code-first…) It’s the production code that pays our bills in the end. (Though I have seen customers these days who demand an acceptance test battery as part of the final delivery. Things seem to go into the right direction…). The test code serves ‘only’ to make the production code work. But it’s the number of delivered features which solely counts at the end of the day - no matter how much test code you wrote or how good it is. With these two things in mind, I tried to optimize my coding process for coding speed – or, in business terms: productivity - without sacrificing the principles of TDD (more than I’d do either way…).  As a result, I consider a ratio of about 3-5/1 for test code vs. production code as normal and desirable. In other words: roughly 60-80% of my code is test code (This might sound heavy, but that is mainly due to the fact that software development standards only begin to evolve. The entire software development profession is very young, historically seen; only at the very beginning, and there are no viable standards yet. If you think about software development as a kind of casting process, where the test code is the mold and the resulting production code is the final product, then the above ratio sounds no longer extraordinary…) Although the above might look like very much unnecessary work at first sight, it’s not. With the aid of the mentioned add-ins, doing all the above is a matter of minutes, sometimes seconds (while writing this post took hours and days…). The most important thing is to have the right tools at hand. Slow developer machines or the lack of a tool or something like that - for ‘saving’ a few 100 bucks -  is just not acceptable and a very bad decision in business terms (though I quite some times have seen and heard that…). Production of high-quality products needs the usage of high-quality tools. This is a platitude that every craftsman knows… The here described round-trip will take me about five to ten minutes in my real-world development practice. I guess it’s about 30% more time compared to developing the ‘traditional’ (code-first) way. But the so manufactured ‘product’ is of much higher quality and massively reduces maintenance costs, which is by far the single biggest cost factor, as I showed in this previous post: It's the maintenance, stupid! (or: Something is rotten in developerland.). In the end, this is a highly cost-effective way of software development… But on the other hand, there clearly is a trade-off here: coding speed vs. code quality/later maintenance costs. The here described development method might be a perfect fit for the overwhelming majority of software projects, but there certainly are some scenarios where it’s not - e.g. if time-to-market is crucial for a software project. So this is a business decision in the end. It’s just that you have to know what you’re doing and what consequences this might have… Some last words First, I’d like to thank Derick Bailey again. His two aforementioned posts (which I strongly recommend for reading) inspired me to think deeply about my own personal way of doing TDD and to clarify my thoughts about it. I wouldn’t have done that without this inspiration. I really enjoy that kind of discussions… I agree with him in all respects. But I don’t know (yet?) how to bring his insights into the described production process without slowing things down. The above described method proved to be very “good enough” in my practical experience. But of course, I’m open to suggestions here… My rationale for now is: If the test is initially red during the red-green-refactor cycle, the ‘right reason’ is: it actually calls the right method, but this method is not yet operational. Later on, when the cycle is finished and the tests become part of the regular, automated Continuous Integration process, ‘red’ certainly must occur for the ‘right reason’: in this phase, ‘red’ MUST mean nothing but an unfulfilled assertion - Fail By Assertion, Not By Anything Else!

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  • DHCP settings out of range Internet shuts off after a few minutes

    - by user263115
    I recently upgraded from windows eight to windows 8.1 I do not know if this has anything to do with anything I have a 64 bit OS. My Internet goes off by itself every 5 minutes even though my wireless icon at the lower right of the screen still shows connected I had an error message in the last event in it said that might DHCP settings were out of range. I get my internet at my house through a wireless portable hotspot through my smart phone. But i haven't ever had any problems before and i only have this problem on this network. If i turn airplane mode on and reset my network card, the internet will come back to life but soon die. i don't experience this problem while on a different network or if i'm on WiFi. This s really annoying please help Windows IP Configuration Host Name . . . . . . . . . . . . : NastyMcnastyJr Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Ethernet adapter Local Area Connection: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : TeamViewer VPN Adapter Physical Address. . . . . . . . . : 00-FF-5D-13-26-21 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Wireless LAN adapter Local Area Connection* 11: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft Wi-Fi Direct Virtual Adapter Physical Address. . . . . . . . . : F6-B7-E2-50-09-38 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Wireless LAN adapter SAMMY McNASTY: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom 802.11n Network Adapter Physical Address. . . . . . . . . : F4-B7-E2-50-09-38 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::3107:66bc:cf1f:c776%4(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.43.3(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Friday, November 1, 2013 9:50:20 PM Lease Expires . . . . . . . . . . : Saturday, November 2, 2013 12:56:46 AM Default Gateway . . . . . . . . . : 192.168.43.1 DHCP Server . . . . . . . . . . . : 192.168.43.1 DHCPv6 IAID . . . . . . . . . . . : 83146722 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-19-F1-98-B4-20-89-84-84-61-BB DNS Servers . . . . . . . . . . . : 192.168.43.1 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter Ethernet: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom NetLink (TM) Gigabit Ethernet Physical Address. . . . . . . . . : 20-89-84-84-61-BB DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Log Name: System Source: Microsoft-Windows-UserPnp Date: 10/26/2013 7:52:23 PM Event ID: 20003 Task Category: (7005) Level: Information Keywords: User: SYSTEM Computer: NastyMcnastyJr Description: Driver Management has concluded the process to add Service vwifibus for Device Instance ID PCI\VEN_14E4&DEV_4727&SUBSYS_E042105B&REV_01\4&3265ADAB&0&00E1 with the following status: 0. Event Xml: 20003 0 4 7005 0 0x8000000000000000 5118 System NastyMcnastyJr vwifibus \SystemRoot\system32\DRIVERS\vwifibus.sys PCI\VEN_14E4&DEV_4727&SUBSYS_E042105B&REV_01\4&3265ADAB&0&00E1 false true 0 Log Name: System Source: Microsoft-Windows-UserPnp Date: 10/19/2013 3:29:12 PM Event ID: 20001 Task Category: (7005) Level: Information Keywords: User: SYSTEM Computer: NastyMcnastyJr Description: Driver Management concluded the process to install driver netbc64.inf_amd64_0df63b5297d0f820\netbc64.inf for Device Instance ID PCI\VEN_14E4&DEV_4727&SUBSYS_E042105B&REV_01\4&3265ADAB&0&00E1 with the following status: 0x0. Event Xml: 20001 0 4 7005 0 0x8000000000000000 2015 System NastyMcnastyJr netbc64.inf_amd64_0df63b5297d0f820\netbc64.inf 6.30.223.102 Microsoft PCI\VEN_14E4&DEV_4727&SUBSYS_E042105B&REV_01\4&3265ADAB&0&00E1 {4D36E972-E325-11CE-BFC1-08002BE10318} false false false 0x0 Broadcom 802.11n Network Adapter Log Name: System Source: Microsoft-Windows-DNS-Client Date: 11/2/2013 12:24:59 AM Event ID: 1014 Task Category: (1014) Level: Warning Keywords: (268435456) User: NETWORK SERVICE Computer: NastyMcnastyJr Description: Name resolution for the name www.google.com timed out after none of the configured DNS servers responded. Event Xml: 1014 0 3 1014 0 0x4000000010000000 34771 System NastyMcnastyJr www.google.com 128 02000000C0A82B01000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

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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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  • Ping "replies" from same computer with 'Destination host unreachable' (no route to other computer)

    - by Srekel
    I've got two computers in a LAN behind a wireless router. One has XP with ip 192.168.1.2 This one has W7 with ip 192.168.1.7 If I try to ping the other one from this computer, I get this: C:\Users\Srekel>ping 192.168.1.2 Pinging 192.168.1.2 with 32 bytes of data: Reply from 192.168.1.7: Destination host unreachable. Reply from 192.168.1.7: Destination host unreachable. Reply from 192.168.1.7: Destination host unreachable. Reply from 192.168.1.7: Destination host unreachable. Ping statistics for 192.168.1.2: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Tracert gives the same result: C:\Users\Srekel>tracert 192.168.1.2 Tracing route to 192.168.1.2 over a maximum of 30 hops 1 Kakburken4 [192.168.1.7] reports: Destination host unreachable. Trace complete. Although I can ping and tracert the router without any problems. I have disabled the firewalls on both computers. The router is set to use DHCP (if that matters). Here is the output from "route". C:\Users\Srekel>route print =========================================================================== Interface List 13...00 25 86 df c6 89 ......TP-LINK Wireless N Adapter 12...e0 cb 4e 26 b9 84 ......Realtek PCIe GBE Family Controller #2 11...e0 cb 4e 26 be 94 ......Realtek PCIe GBE Family Controller 1...........................Software Loopback Interface 1 16...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #2 14...00 00 00 00 00 00 00 e0 Teredo Tunneling Pseudo-Interface =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.7 20 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 192.168.1.0 255.255.255.0 On-link 192.168.1.7 276 192.168.1.7 255.255.255.255 On-link 192.168.1.7 276 192.168.1.255 255.255.255.255 On-link 192.168.1.7 276 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 192.168.1.7 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 192.168.1.7 276 =========================================================================== Persistent Routes: None IPv6 Route Table =========================================================================== Active Routes: If Metric Network Destination Gateway 14 58 ::/0 On-link 1 306 ::1/128 On-link 14 58 2001::/32 On-link 14 306 2001:0:5ef5:73ba:881:20c1:3f57:fef8/128 On-link 14 306 fe80::/64 On-link 14 306 fe80::881:20c1:3f57:fef8/128 On-link 1 306 ff00::/8 On-link 14 306 ff00::/8 On-link =========================================================================== Persistent Routes: None I've set up and debugged a few networks in my life but I'm not really an advanced network user, so I'm not sure what might be wrong. Any ideas? Oh, and pinging this computer from the other computer doesn't work either. EDIT: Adding arp output: C:\Users\Srekel>arp -a Interface: 192.168.1.7 --- 0xd Internet Address Physical Address Type 192.168.1.1 00-1f-33-ef-28-01 dynamic 192.168.1.255 ff-ff-ff-ff-ff-ff static 224.0.0.22 01-00-5e-00-00-16 static 224.0.0.252 01-00-5e-00-00-fc static 239.255.255.250 01-00-5e-7f-ff-fa static 255.255.255.255 ff-ff-ff-ff-ff-ff static Adding ipconfig... C:\Users\Srekel>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : Kakburken4 Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Wireless LAN adapter Wireless Network Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : TP-LINK Wireless N Adapter Physical Address. . . . . . . . . : 00-25-86-DF-C6-89 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.1.7(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : 09 April 2010 23:09:45 Lease Expires . . . . . . . . . . : 10 April 2010 23:09:45 Default Gateway . . . . . . . . . : 192.168.1.1 DHCP Server . . . . . . . . . . . : 192.168.1.1 DNS Servers . . . . . . . . . . . : 192.168.1.1 NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter Local Area Connection 2: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller #2 Physical Address. . . . . . . . . : E0-CB-4E-26-B9-84 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Ethernet adapter Local Area Connection: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller Physical Address. . . . . . . . . : E0-CB-4E-26-BE-94 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Tunnel adapter isatap.{74D5C406-894E-4000-8DE7-6AAEBF7C8382}: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2 Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Tunnel adapter Teredo Tunneling Pseudo-Interface: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv6 Address. . . . . . . . . . . : 2001:0:5ef5:73ba:881:20c1:3f57:fef8(Preferred) Link-local IPv6 Address . . . . . : fe80::881:20c1:3f57:fef8%14(Preferred) Default Gateway . . . . . . . . . : :: NetBIOS over Tcpip. . . . . . . . : Disabled

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  • Building applications with WCF - Intro

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

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  • Part 2&ndash;Load Testing In The Cloud

    - by Tarun Arora
    Welcome to Part 2, In Part 1 we discussed the advantages of creating a Test Rig in the cloud, the Azure edge and the Test Rig Topology we want to get to. In Part 2, Let’s start by understanding the components of Azure we’ll be making use of followed by manually putting them together to create the test rig, so… let’s get down dirty start setting up the Test Rig.  What Components of Azure will I be using for building the Test Rig in the Cloud? To run the Test Agents we’ll make use of Windows Azure Compute and to enable communication between Test Controller and Test Agents we’ll make use of Windows Azure Connect.  Azure Connect The Test Controller is on premise and the Test Agents are in the cloud (How will they talk?). To enable communication between the two, we’ll make use of Windows Azure Connect. With Windows Azure Connect, you can use a simple user interface to configure IPsec protected connections between computers or virtual machines (VMs) in your organization’s network, and roles running in Windows Azure. With this you can now join Windows Azure role instances to your domain, so that you can use your existing methods for domain authentication, name resolution, or other domain-wide maintenance actions. For more details refer to an overview of Windows Azure connect. A very useful video explaining everything you wanted to know about Windows Azure connect.  Azure Compute Windows Azure compute provides developers a platform to host and manage applications in Microsoft’s data centres across the globe. A Windows Azure application is built from one or more components called ‘roles.’ Roles come in three different types: Web role, Worker role, and Virtual Machine (VM) role, we’ll be using the Worker role to set up the Test Agents. A very nice blog post discussing the difference between the 3 role types. Developers are free to use the .NET framework or other software that runs on Windows with the Worker role or Web role. Developers can also create applications using languages such as PHP and Java. More on Windows Azure Compute. Each Windows Azure compute instance represents a virtual server... Virtual Machine Size CPU Cores Memory Cost Per Hour Extra Small Shared 768 MB $0.04 Small 1 1.75 GB $0.12 Medium 2 3.50 GB $0.24 Large 4 7.00 GB $0.48 Extra Large 8 14.00 GB $0.96   You might want to review the Windows Azure Pricing FAQ. Let’s Get Started building the Test Rig… Configuration Machine Role Comments VM – 1 Domain Controller for Playpit.com On Premise VM – 2 TFS, Test Controller On Premise VM – 3 Test Agent Cloud   In this blog post I would assume that you have the domain, Team Foundation Server and Test Controller Installed and set up already. If not, please refer to the TFS 2010 Installation Guide and this walkthrough on MSDN to set up your Test Controller. You can also download a preconfigured TFS 2010 VM from Brian Keller's blog, Brian also has some great hands on Labs on TFS 2010 that you may want to explore. I. Lets start building VM – 3: The Test Agent Download the Windows Azure SDK and Tools Open Visual Studio and create a new Windows Azure Project using the Cloud Template                   Choose the Worker Role for reasons explained in the earlier post         The WorkerRole.cs implements the Run() and OnStart() methods, no code changes required. You should be able to compile the project and run it in the compute emulator (The compute emulator should have been installed as part of the Windows Azure Toolkit) on your local machine.                   We will only be making changes to WindowsAzureProject, open ServiceDefinition.csdef. Ensure that the vmsize is small (remember the cost chart above). Import the “Connect” module. I am importing the Connect module because I need to join the Worker role VM to the Playpit domain. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WorkerRole name="WorkerRole1" vmsize="Small"> <Imports> <Import moduleName="Diagnostics" /> <Import moduleName="Connect"/> </Imports> </WorkerRole> </ServiceDefinition> Go to the ServiceConfiguration.Cloud.cscfg and note that settings with key ‘Microsoft.WindowsAzure.Plugins.Connect.%%%%’ have been added to the configuration file. This is because you decided to import the connect module. See the config below. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*"> <Role name="WorkerRole1"> <Instances count="1" /> <ConfigurationSettings> <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.ActivationToken" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Refresh" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.WaitForConnectivity" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Upgrade" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.EnableDomainJoin" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainFQDN" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainControllerFQDN" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainAccountName" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainPassword" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainOU" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Administrators" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainSiteName" value="" /> </ConfigurationSettings> </Role> </ServiceConfiguration>             Let’s go step by step and understand all the highlighted parameters and where you can find the values for them.       osFamily – By default this is set to 1 (Windows Server 2008 SP2). Change this to 2 if you want the Windows Server 2008 R2 operating system. The Advantage of using osFamily = “2” is that you get Powershell 2.0 rather than Powershell 1.0. In Powershell 2.0 you could simply use “powershell -ExecutionPolicy Unrestricted ./myscript.ps1” and it will work while in Powershell 1.0 you will have to change the registry key by including the following in your command file “reg add HKLM\Software\Microsoft\PowerShell\1\ShellIds\Microsoft.PowerShell /v ExecutionPolicy /d Unrestricted /f” before you can execute any power shell. The other reason you might want to move to os2 is if you wanted IIS 7.5.       Activation Token – To enable communication between the on premise machine and the Windows Azure Worker role VM both need to have the same token. Log on to Windows Azure Management Portal, click on Connect, click on Get Activation Token, this should give you the activation token, copy the activation token to the clipboard and paste it in the configuration file. Note – Later in the blog I’ll be showing you how to install connect on the on premise machine.                       EnableDomainJoin – Set the value to true, ofcourse we want to join the on windows azure worker role VM to the domain.       DomainFQDN, DomainControllerFQDN, DomainAccountName, DomainPassword, DomainOU, Administrators – This information is specific to your domain. I have extracted this information from the ‘service manager’ and ‘Active Directory Users and Computers’. Also, i created a new Domain-OU namely ‘CloudInstances’ so all my cloud instances joined to my domain show up here, this is optional. You can encrypt the DomainPassword – refer to the instructions here. Or hold fire, I’ll be covering that when i come to certificates and encryption in the coming section.       Now once you have filled all this information up, the configuration file should look something like below, <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="2" osVersion="*"> <Role name="WorkerRole1"> <Instances count="1" /> <ConfigurationSettings> <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.ActivationToken" value="45f55fea-f194-4fbc-b36e-25604faac784" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Refresh" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.WaitForConnectivity" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Upgrade" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.EnableDomainJoin" value="true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainFQDN" value="play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainControllerFQDN" value="WIN-KUDQMQFGQOL.play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainAccountName" value="playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainPassword" value="************************" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainOU" value="OU=CloudInstances, DC=Play, DC=Pit, DC=com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Administrators" value="Playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainSiteName" value="" /> </ConfigurationSettings> </Role> </ServiceConfiguration> Next we will be enabling the Remote Desktop module in to the ServiceDefinition.csdef, we could make changes manually or allow a beautiful wizard to help us make changes. I prefer the second option. So right click on the Windows Azure project and choose Publish       Now once you get the publish wizard, if you haven’t already you would be asked to import your Windows Azure subscription, this is simply the Msdn subscription activation key xml. Once you have done click Next to go to the Settings page and check ‘Enable Remote Desktop for all roles’.       As soon as you do that you get another pop up asking you the details for the user that you would be logging in with (make sure you enter a reasonable expiry date, you do not want the user account to expire today). Notice the more information tag at the bottom, click that to get access to the certificate section. See screen shot below.       From the drop down select the option to create a new certificate        In the pop up window enter the friendly name for your certificate. In my case I entered ‘WAC – Test Rig’ and click ok. This will create a new certificate for you. Click on the view button to see the certificate details. Do you see the Thumbprint, this is the value that will go in the config file (very important). Now click on the Copy to File button to copy the certificate, we will need to import the certificate to the windows Azure Management portal later. So, make sure you save it a safe location.                                Click Finish and enter details of the user you would like to create with permissions for remote desktop access, once you have entered the details on the ‘Remote desktop configuration’ screen click on Ok. From the Publish Windows Azure Wizard screen press Cancel. Cancel because we don’t want to publish the role just yet and Yes because we want to save all the changes in the config file.       Now if you go to the ServiceDefinition.csdef file you will see that the RemoteAccess and RemoteForwarder roles have been imported for you. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WorkerRole name="WorkerRole1" vmsize="Small"> <Imports> <Import moduleName="Diagnostics" /> <Import moduleName="Connect" /> <Import moduleName="RemoteAccess" /> <Import moduleName="RemoteForwarder" /> </Imports> </WorkerRole> </ServiceDefinition> Now go to the ServiceConfiguration.Cloud.cscfg file and you see a whole bunch for setting “Microsoft.WindowsAzure.Plugins.RemoteAccess.%%%” values added for you. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="WindowsAzureProject2" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="2" osVersion="*"> <Role name="WorkerRole1"> <Instances count="1" /> <ConfigurationSettings> <Setting name="Microsoft.WindowsAzure.Plugins.Diagnostics.ConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.ActivationToken" value="45f55fea-f194-4fbc-b36e-25604faac784" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Refresh" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.WaitForConnectivity" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Upgrade" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.EnableDomainJoin" value="true" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainFQDN" value="play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainControllerFQDN" value="WIN-KUDQMQFGQOL.play.pit.com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainAccountName" value="playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainPassword" value="************************" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainOU" value="OU=CloudInstances, DC=Play, DC=Pit, DC=com" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.Administrators" value="Playpit\Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.Connect.DomainSiteName" value="" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.Enabled" value="true" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountUsername" value="Administrator" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountEncryptedPassword" value="MIIBnQYJKoZIhvcNAQcDoIIBjjCCAYoCAQAxggFOMIIBSgIBADAyMB4xHDAaBgNVBAMME1dpbmRvd 3MgQXp1cmUgVG9vbHMCEGa+B46voeO5T305N7TSG9QwDQYJKoZIhvcNAQEBBQAEggEABg4ol5Xol66Ip6QKLbAPWdmD4ae ADZ7aKj6fg4D+ATr0DXBllZHG5Umwf+84Sj2nsPeCyrg3ZDQuxrfhSbdnJwuChKV6ukXdGjX0hlowJu/4dfH4jTJC7sBWS AKaEFU7CxvqYEAL1Hf9VPL5fW6HZVmq1z+qmm4ecGKSTOJ20Fptb463wcXgR8CWGa+1w9xqJ7UmmfGeGeCHQ4QGW0IDSBU6ccg vzF2ug8/FY60K1vrWaCYOhKkxD3YBs8U9X/kOB0yQm2Git0d5tFlIPCBT2AC57bgsAYncXfHvPesI0qs7VZyghk8LVa9g5IqaM Cp6cQ7rmY/dLsKBMkDcdBHuCTAzBgkqhkiG9w0BBwEwFAYIKoZIhvcNAwcECDRVifSXbA43gBApNrp40L1VTVZ1iGag+3O1" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountExpiration" value="2012-11-27T23:59:59.0000000+00:00" /> <Setting name="Microsoft.WindowsAzure.Plugins.RemoteForwarder.Enabled" value="true" /> </ConfigurationSettings> <Certificates> <Certificate name="Microsoft.WindowsAzure.Plugins.RemoteAccess.PasswordEncryption" thumbprint="AA23016CF0BDFC344400B5B82706B608B92E4217" thumbprintAlgorithm="sha1" /> </Certificates> </Role> </ServiceConfiguration>          Okay let’s look at them one at a time,       Enabled - Yes, we would like to enable Remote Access.       AccountUserName – This is the user name you entered while you were on the publish windows azure role screen, as detailed above.       AccountEncrytedPassword – Try and decode that, the certificate is used to encrypt the password you specified for the user account. Remember earlier i said, either use the instructions or wait and i’ll be showing you encryption, now the user account i am using for rdp has the same password as my domain password, so i can simply copy the value of the AccountEncryptedPassword to the DomainPassword as well.       AccountExpiration – This is the expiration as you specified in the wizard earlier, make sure your account does not expire today.       Remote Forwarder – Check out the documentation, below is how I understand it, -- One role in an application that implements a remote desktop connection must import the RemoteForwarder module. The two modules work together to enable the remote desktop connections to role instances. -- If you have multiple roles defined in the service model, it does not matter which role you add the RemoteForwarder module to, but you must add it to only one of the role definitions.       Certificate – Remember the certificate thumbprint from the wizard, the on premise machine and windows azure role machine that need to speak to each other must have the same thumbprint. More on that when we install Windows Azure connect Endpoints on the on premise machine. As i said earlier, in this blog post, I’ll be showing you the manual process so i won’t be scripting any star up tasks to install the test agent or register the test agent with the TFS Server. I’ll be showing you all this cool stuff in the next blog post, that’s because it’s important to understand the manual side of it, it becomes easier for you to troubleshoot in case something fails. Having said that, the changes we have made are sufficient to spin up the Windows Azure Worker Role aka Test Agent VM, have it connected with the play.pit.com domain and have remote access enabled on it. Before we deploy the Test Agent VM we need to set up Windows Azure Connect on the TFS Server. II. Windows Azure Connect: Setting up Connect on VM – 2 i.e. TFS & Test Controller Glad you made it so far, now to enable communication between the on premise TFS/Test Controller and Azure-ed Test Agent we need to enable communication. We have set up the Azure connect module in the Test Agent configuration, now the connect end points need to be enabled on the on premise machines, let’s have a look at how we can do this. Log on to VM – 2 running the TFS Server and Test Controller Log on to the Windows Azure Management Portal and click on Virtual Network Click on Virtual Network, if you already have a subscription you should see the below screen shot, if not, you would be asked to complete the subscription first        Click on Install Local Endpoints from the top left on the panel and you get a url appended with a token id in it, remember the token i showed you earlier, in theory the token you get here should match the token you added to the Test Agent config file.        Copy the url to the clip board and paste it in IE explorer (important, the installation at present only works out of IE and you need to have cookies enabled in order to complete the installation). As stated in the pop up, you can NOT download and run the software later, you need to run it as is, since it contains a token. Once the installation completes you should see the Windows Azure connect icon in the system tray.                         Right click the Azure Connect icon, choose Diagnostics and refer to this link for diagnostic detail terminology. NOTE – Unfortunately I could not see the Windows Azure connect icon in the system tray, a bit of binging with Google revealed that the azure connect icon is only shown when the ‘Windows Azure Connect Endpoint’ Service is started. So go to services.msc and make sure that the service is started, if not start it, unfortunately again, the service did not start for me on a manual start and i realised that one of the dependant services was disabled, you can look at the service dependencies and start them and then start windows azure connect. Bottom line, you need to start Windows Azure connect service before you can proceed. Please refer here on MSDN for more on Troubleshooting Windows Azure connect. (Follow the next step as well)   Now go back to the Windows Azure Management Portal and from Groups and Roles create a new group, lets call it ‘Test Rig’. Make sure you add the VM – 2 (the TFS Server VM where you just installed the endpoint).       Now if you go back to the Azure Connect icon in the system tray and click ‘Refresh Policy’ you will notice that the disconnected status of the icon should change to ready for connection. III. Importing Certificate in to Windows Azure Management Portal But before that you need to import the certificate you created in Step I in to the Windows Azure Management Portal. Log on to the Windows Azure Management Portal and click on ‘Hosted Services, Storage Accounts & CDN’ and then ‘Management Certificates’ followed by Add Certificates as shown in the screen shot below        Browse to the location where you saved the certificate earlier, remember… Refer to Step I in case you forgot.        Now you should be able to see the imported certificate here, make sure the thumbprint of the certificate matches the one you inserted in the config files        IV. Publish Windows Azure Worker Role aka Test Agent Having completed I, II and III, you are ready to publish the Test Agent VM – 3 to the cloud. Go to Visual Studio and right click the Windows Azure project and select Publish. Verify the infomration in the wizard, from the advanced settings tab, you can also enabled capture of intellitrace or profiling information.         Click Next and Click Publish! From the view menu bar select the Windows Azure Activity Log window.       Now you should be able to see the deployment progress in real time.             In the Windows Azure Management Portal, you should also be able to see the progress of creation of a new Worker Role.       Once the deployment is complete you should be able to RDP (go to run prompt type mstsc and in the pop up the machine name) in to the Test Agent Worker Role VM from the Playpit network using the domain admin user account. In case you are unable to log in to the Test Agent using the domain admin user account it means the process of joining the Test Agent to the domain has failed! But the good news is, because you imported the connect module, you can connect to the Test Agent machine using Windows Azure Management Portal and troubleshoot the reason for failure, you will be able to log in with the user name and password you specified in the config file for the keys ‘RemoteAccess.AccountUsername, RemoteAccess.EncryptedPassword (just that enter the password unencrypted)’, fix it or manually join the machine to the domain. Once you have managed to Join the Test Agent VM to the Domain move to the next step.      So, log in to the Test Agent Worker Role VM with the Playpit Domain Administrator and verify that you can log in, the machine is connected to the domain and the connect service is successfully running. If yes, give your self a pat on the back, you are 80% mission accomplished!         Go to the Windows Azure Management Portal and click on Virtual Network, click on Groups and Roles and click on Test Rig, click Edit Group, the edit the Test Rig group you created earlier. In the Connect to section, click on Add to select the worker role you have just deployed. Also, check the ‘Allow connections between endpoints in the group’ with this you will enable to communication between test controller and test agents and test agents/test agents. Click Save.      Now, you are ready to deploy the Test Agent software on the Worker Role Test Agent VM and configure it to work with the Test Controller. V. Configuring VM – 3: Installing Test Agent and Associating Test Agent to Controller Log in to the Worker Role Test Agent VM that you have just successfully deployed, make sure you log in with the domain administrator account. Download the All Agents software from MSDN, ‘en_visual_studio_agents_2010_x86_x64_dvd_509679.iso’, extract the iso and navigate to where you have extracted the iso. In my case, i have extracted the iso to “C:\Resources\Temp\VsAgentSetup”. Open the Test Agent folder and double click on setup.exe. Once you have installed the Test Agent you should reach the configuration window. If you face any issues installing TFS Test Agent on the VM, refer to the walkthrough on MSDN.       Once you have successfully installed the Test Agent software you will need to configure the test agent. Right click the test agent configuration tool and run as a different user. i.e. an Administrator. This is really to run the configuration wizard with elevated privileges (you might have UAC block something's otherwise).        In the run options, you can select ‘service’ you do not need to run the agent as interactive un less you are running coded UI tests. I have specified the domain administrator to connect to the TFS Test Controller. In real life, i would never do that, i would create a separate test user service account for this purpose. But for the blog post, we are using the most powerful user so that any policies or restrictions don’t block you.        Click the Apply Settings button and you should be all green! If not, the summary usually gives helpful error messages that you can resolve and proceed. As per my experience, you may run in to either a permission or a firewall blocking communication issue.        And now the moment of truth! Go to VM –2 open up Visual Studio and from the Test Menu select Manage Test Controller       Mission Accomplished! You should be able to see the Test Agent that you have just configured here,         VI. Creating and Running Load Tests on your brand new Azure-ed Test Rig I have various blog posts on Performance Testing with Visual Studio Ultimate, you can follow the links and videos below, Blog Posts: - Part 1 – Performance Testing using Visual Studio 2010 Ultimate - Part 2 – Performance Testing using Visual Studio 2010 Ultimate - Part 3 – Performance Testing using Visual Studio 2010 Ultimate Videos: - Test Tools Configuration & Settings in Visual Studio - Why & How to Record Web Performance Tests in Visual Studio Ultimate - Goal Driven Load Testing using Visual Studio Ultimate Now that you have created your load tests, there is one last change you need to make before you can run the tests on your Azure Test Rig, create a new Test settings file, and change the Test Execution method to ‘Remote Execution’ and select the test controller you have configured the Worker Role Test Agent against in our case VM – 2 So, go on, fire off a test run and see the results of the test being executed on the Azur-ed Test Rig. Review and What’s next? A quick recap of the benefits of running the Test Rig in the cloud and what i will be covering in the next blog post AND I would love to hear your feedback! Advantages Utilizing the power of Azure compute to run a heavy virtual user load. Benefiting from the Azure flexibility, destroy Test Agents when not in use, takes < 25 minutes to spin up a new Test Agent. Most important test Network Latency, (network latency and speed of connection are two different things – usually network latency is very hard to test), by placing the Test Agents in Microsoft Data centres around the globe, one can actually test the lag in transferring the bytes not because of a slow connection but because the page has been requested from the other side of the globe. Next Steps The process of spinning up the Test Agents in windows Azure is not 100% automated. I am working on the Worker process and power shell scripts to make the role deployment, unattended install of test agent software and registration of the test agent to the test controller automated. In the next blog post I will show you how to make the complete process unattended and automated. Remember to subscribe to http://feeds.feedburner.com/TarunArora. Hope you enjoyed this post, I would love to hear your feedback! If you have any recommendations on things that I should consider or any questions or feedback, feel free to leave a comment. See you in Part III.   Share this post : CodeProject

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  • In WCF How Can I add SAML 2.0 assertion to SOAP Header?

    - by Tone
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</wsu:Timestamp> <saml2:Assertion xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:exc14n="http://www.w3.org/2001/10/xml-exc-c14n#" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" xmlns:xs="http://www.w3.org/2001/XMLSchema" ID="bd1ecf8d-a6d8-488d-9183-a11227c6a219" IssueInstant="2010-05-26T03:51:57.959Z" Version="2.0"> <saml2:Issuer Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">CN=SAML User,OU=SU,O=SAML User,L=Los Angeles,ST=CA,C=US</saml2:Issuer> <saml2:Subject> <saml2:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">UID=kskagerb</saml2:NameID> <saml2:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:holder-of-key"> <saml2:SubjectConfirmationData> <ds:KeyInfo> <ds:KeyValue> <ds:RSAKeyValue> <ds:Modulus>p4jUkEUg..gwO7U=</ds:Modulus> <ds:Exponent>AQAB</ds:Exponent> </ds:RSAKeyValue> </ds:KeyValue> </ds:KeyInfo> </saml2:SubjectConfirmationData> </saml2:SubjectConfirmation> </saml2:Subject> <saml2:AuthnStatement AuthnInstant="2009-04-16T13:15:39.000Z" SessionIndex="987"> <saml2:SubjectLocality Address="158.147.185.168" DNSName="cs.myharris.net"/> <saml2:AuthnContext> <saml2:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:X509</saml2:AuthnContextClassRef> </saml2:AuthnContext> </saml2:AuthnStatement> <saml2:AttributeStatement> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:subject-id"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">Karl S Skagerberg</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:organization"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">InternalTest2</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:organization-id"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">2.2</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:nhin:names:saml:homeCommunityId"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">2.16.840.1.113883.3.441</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xacml:2.0:subject:role"> <saml2:AttributeValue> <hl7:Role xmlns:hl7="urn:hl7-org:v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" code="307969004" codeSystem="2.16.840.1.113883.6.96" codeSystemName="SNOMED_CT" displayName="Public Health" xsi:type="hl7:CE"/> </saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:purposeofuse"> <saml2:AttributeValue> <hl7:PurposeForUse xmlns:hl7="urn:hl7-org:v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" code="PUBLICHEALTH" codeSystem="2.16.840.1.113883.3.18.7.1" codeSystemName="nhin-purpose" displayName="Use or disclosure of Psychotherapy Notes" xsi:type="hl7:CE"/> </saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xacml:2.0:resource:resource-id"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">500000000^^^&amp;1.1&amp;ISO</saml2:AttributeValue> </saml2:Attribute> </saml2:AttributeStatement> <saml2:AuthzDecisionStatement Decision="Permit" Resource="https://158.147.185.168:8181/SamlReceiveService/SamlProcessWS"> <saml2:Action Namespace="urn:oasis:names:tc:SAML:1.0:action:rwedc">Execute</saml2:Action> <saml2:Evidence> <saml2:Assertion ID="40df7c0a-ff3e-4b26-baeb-f2910f6d05a9" IssueInstant="2009-04-16T13:10:39.093Z" Version="2.0"> <saml2:Issuer Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">CN=SAML User,OU=Harris,O=HITS,L=Melbourne,ST=FL,C=US</saml2:Issuer> <saml2:Conditions NotBefore="2009-04-16T13:10:39.093Z" NotOnOrAfter="2009-12-31T12:00:00.000Z"/> <saml2:AttributeStatement> <saml2:Attribute Name="AccessConsentPolicy" NameFormat="http://www.hhs.gov/healthit/nhin"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">Claim-Ref-1234</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="InstanceAccessConsentPolicy" NameFormat="http://www.hhs.gov/healthit/nhin"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">Claim-Instance-1</saml2:AttributeValue> </saml2:Attribute> </saml2:AttributeStatement> </saml2:Assertion> </saml2:Evidence> </saml2:AuthzDecisionStatement> <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"> <ds:SignedInfo> <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> <ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/> <ds:Reference URI="#bd1ecf8d-a6d8-488d-9183-a11227c6a219"> <ds:Transforms> <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/> <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> </ds:Transforms> <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <ds:DigestValue>ONbZqPUyFVPMx4v9vvpJGNB4cao=</ds:DigestValue> </ds:Reference> </ds:SignedInfo> <ds:SignatureValue>Dm/aW5bB..pF93s=</ds:SignatureValue> <ds:KeyInfo> <ds:KeyValue> <ds:RSAKeyValue> <ds:Modulus>p4jUkEU..bzqgwO7U=</ds:Modulus> <ds:Exponent>AQAB</ds:Exponent> </ds:RSAKeyValue> </ds:KeyValue> </ds:KeyInfo> </ds:Signature> </saml2:Assertion> <ds:Signature xmlns:ns17="http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512" xmlns:ns16="http://www.w3.org/2003/05/soap-envelope" Id="_2"> <ds:SignedInfo> <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"> <exc14n:InclusiveNamespaces PrefixList="wsse S"/> </ds:CanonicalizationMethod> <ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/> <ds:Reference URI="#_1"> <ds:Transforms> <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"> <exc14n:InclusiveNamespaces PrefixList="wsu wsse S"/> </ds:Transform> </ds:Transforms> <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <ds:DigestValue> <Include xmlns="http://www.w3.org/2004/08/xop/include" href="cid:[email protected]"/> </ds:DigestValue> </ds:Reference> </ds:SignedInfo> <ds:SignatureValue> <Include xmlns="http://www.w3.org/2004/08/xop/include" href="cid:[email protected]"/> </ds:SignatureValue> <ds:KeyInfo> <wsse:SecurityTokenReference wsse11:TokenType="http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLV2.0"> <wsse:KeyIdentifier ValueType="http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLID">bd1ecf8d-a6d8-488d-9183-a11227c6a219</wsse:KeyIdentifier> </wsse:SecurityTokenReference> </ds:KeyInfo> </ds:Signature> </wsse:Security> </S:Header> I've been researching for days and cannot seem to come up with a straightforward way of doing this in WCF. The web service is running on Glassfish and is soap 1.1, I've tried using all the packaged wcf bindings but have not been able to get them to work. I started down the path of using a MessageInspector, and wrote one but then realized there must be a better way, surely WCF provides some way to insert saml 2.0 assertions. I've made the most progress writing a custom binding - i've been able to get the timestamp and signature nodes in the soap header, but cannot for the life of me figure out the saml assertion. Any ideas? public static System.ServiceModel.Channels.Binding BuildCONNECTCustomBinding() { TransportSecurityBindingElement transportSecurityBindingElement = SecurityBindingElement.CreateCertificateOverTransportBindingElement(MessageSecurityVersion.WSSecurity10WSTrustFebruary2005WSSecureConversationFebruary2005WSSecurityPolicy11BasicSecurityProfile10); TextMessageEncodingBindingElement textMessageEncodingBindingElement = new TextMessageEncodingBindingElement(MessageVersion.Soap11WSAddressing10, System.Text.Encoding.UTF8); HttpsTransportBindingElement httpsTransportBindingElement = new HttpsTransportBindingElement(); SecurityTokenReferenceType securityTokenReference = new SecurityTokenReferenceType(); BindingElementCollection bindingElementCollection = new BindingElementCollection(); bindingElementCollection.Add(transportSecurityBindingElement); bindingElementCollection.Add(textMessageEncodingBindingElement); bindingElementCollection.Add(httpsTransportBindingElement); CustomBinding cb = new CustomBinding(bindingElementCollection); cb.CreateBindingElements(); return cb; }

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  • In a WCF Client How Can I add SAML 2.0 assertion to SOAP Header?

    - by Tone
    I'm trying to add the saml 2.0 assertion node from the soap header example below - I came across the samlassertion type in the .net framework but that looks like it is only for saml 1.1. <S:Header> <To xmlns="http://www.w3.org/2005/08/addressing">https://rs1.greenwaymedical.com:8181/CONNECTGateway/EntityService/NhincProxyXDRRequestSecured</To> <Action xmlns="http://www.w3.org/2005/08/addressing">tns:ProvideAndRegisterDocumentSet-bRequest_Request</Action> <ReplyTo xmlns="http://www.w3.org/2005/08/addressing"> <Address>http://www.w3.org/2005/08/addressing/anonymous</Address> </ReplyTo> <MessageID xmlns="http://www.w3.org/2005/08/addressing">uuid:662ee047-3437-4781-a8d2-ee91bc940ef0</MessageID> <wsse:Security S:mustUnderstand="1"> <wsu:Timestamp xmlns:ns17="http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512" xmlns:ns16="http://www.w3.org/2003/05/soap-envelope" wsu:Id="_1"> <wsu:Created>2010-05-26T03:51:57Z</wsu:Created> <wsu:Expires>2010-05-26T03:56:57Z</wsu:Expires> </wsu:Timestamp> <saml2:Assertion xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:exc14n="http://www.w3.org/2001/10/xml-exc-c14n#" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" xmlns:xs="http://www.w3.org/2001/XMLSchema" ID="bd1ecf8d-a6d8-488d-9183-a11227c6a219" IssueInstant="2010-05-26T03:51:57.959Z" Version="2.0"> <saml2:Issuer Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">CN=SAML User,OU=SU,O=SAML User,L=Los Angeles,ST=CA,C=US</saml2:Issuer> <saml2:Subject> <saml2:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">UID=kskagerb</saml2:NameID> <saml2:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:holder-of-key"> <saml2:SubjectConfirmationData> <ds:KeyInfo> <ds:KeyValue> <ds:RSAKeyValue> <ds:Modulus>p4jUkEUg..gwO7U=</ds:Modulus> <ds:Exponent>AQAB</ds:Exponent> </ds:RSAKeyValue> </ds:KeyValue> </ds:KeyInfo> </saml2:SubjectConfirmationData> </saml2:SubjectConfirmation> </saml2:Subject> <saml2:AuthnStatement AuthnInstant="2009-04-16T13:15:39.000Z" SessionIndex="987"> <saml2:SubjectLocality Address="158.147.185.168" DNSName="cs.myharris.net"/> <saml2:AuthnContext> <saml2:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:X509</saml2:AuthnContextClassRef> </saml2:AuthnContext> </saml2:AuthnStatement> <saml2:AttributeStatement> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:subject-id"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">Karl S Skagerberg</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:organization"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">InternalTest2</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:organization-id"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">2.2</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:nhin:names:saml:homeCommunityId"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">2.16.840.1.113883.3.441</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xacml:2.0:subject:role"> <saml2:AttributeValue> <hl7:Role xmlns:hl7="urn:hl7-org:v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" code="307969004" codeSystem="2.16.840.1.113883.6.96" codeSystemName="SNOMED_CT" displayName="Public Health" xsi:type="hl7:CE"/> </saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xspa:1.0:subject:purposeofuse"> <saml2:AttributeValue> <hl7:PurposeForUse xmlns:hl7="urn:hl7-org:v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" code="PUBLICHEALTH" codeSystem="2.16.840.1.113883.3.18.7.1" codeSystemName="nhin-purpose" displayName="Use or disclosure of Psychotherapy Notes" xsi:type="hl7:CE"/> </saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="urn:oasis:names:tc:xacml:2.0:resource:resource-id"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">500000000^^^&amp;1.1&amp;ISO</saml2:AttributeValue> </saml2:Attribute> </saml2:AttributeStatement> <saml2:AuthzDecisionStatement Decision="Permit" Resource="https://158.147.185.168:8181/SamlReceiveService/SamlProcessWS"> <saml2:Action Namespace="urn:oasis:names:tc:SAML:1.0:action:rwedc">Execute</saml2:Action> <saml2:Evidence> <saml2:Assertion ID="40df7c0a-ff3e-4b26-baeb-f2910f6d05a9" IssueInstant="2009-04-16T13:10:39.093Z" Version="2.0"> <saml2:Issuer Format="urn:oasis:names:tc:SAML:1.1:nameid-format:X509SubjectName">CN=SAML User,OU=Harris,O=HITS,L=Melbourne,ST=FL,C=US</saml2:Issuer> <saml2:Conditions NotBefore="2009-04-16T13:10:39.093Z" NotOnOrAfter="2009-12-31T12:00:00.000Z"/> <saml2:AttributeStatement> <saml2:Attribute Name="AccessConsentPolicy" NameFormat="http://www.hhs.gov/healthit/nhin"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">Claim-Ref-1234</saml2:AttributeValue> </saml2:Attribute> <saml2:Attribute Name="InstanceAccessConsentPolicy" NameFormat="http://www.hhs.gov/healthit/nhin"> <saml2:AttributeValue xmlns:ns6="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns7="http://www.w3.org/2001/XMLSchema" ns6:type="ns7:string">Claim-Instance-1</saml2:AttributeValue> </saml2:Attribute> </saml2:AttributeStatement> </saml2:Assertion> </saml2:Evidence> </saml2:AuthzDecisionStatement> <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"> <ds:SignedInfo> <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> <ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/> <ds:Reference URI="#bd1ecf8d-a6d8-488d-9183-a11227c6a219"> <ds:Transforms> <ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/> <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> </ds:Transforms> <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <ds:DigestValue>ONbZqPUyFVPMx4v9vvpJGNB4cao=</ds:DigestValue> </ds:Reference> </ds:SignedInfo> <ds:SignatureValue>Dm/aW5bB..pF93s=</ds:SignatureValue> <ds:KeyInfo> <ds:KeyValue> <ds:RSAKeyValue> <ds:Modulus>p4jUkEU..bzqgwO7U=</ds:Modulus> <ds:Exponent>AQAB</ds:Exponent> </ds:RSAKeyValue> </ds:KeyValue> </ds:KeyInfo> </ds:Signature> </saml2:Assertion> <ds:Signature xmlns:ns17="http://docs.oasis-open.org/ws-sx/ws-secureconversation/200512" xmlns:ns16="http://www.w3.org/2003/05/soap-envelope" Id="_2"> <ds:SignedInfo> <ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"> <exc14n:InclusiveNamespaces PrefixList="wsse S"/> </ds:CanonicalizationMethod> <ds:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/> <ds:Reference URI="#_1"> <ds:Transforms> <ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"> <exc14n:InclusiveNamespaces PrefixList="wsu wsse S"/> </ds:Transform> </ds:Transforms> <ds:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <ds:DigestValue> <Include xmlns="http://www.w3.org/2004/08/xop/include" href="cid:[email protected]"/> </ds:DigestValue> </ds:Reference> </ds:SignedInfo> <ds:SignatureValue> <Include xmlns="http://www.w3.org/2004/08/xop/include" href="cid:[email protected]"/> </ds:SignatureValue> <ds:KeyInfo> <wsse:SecurityTokenReference wsse11:TokenType="http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLV2.0"> <wsse:KeyIdentifier ValueType="http://docs.oasis-open.org/wss/oasis-wss-saml-token-profile-1.1#SAMLID">bd1ecf8d-a6d8-488d-9183-a11227c6a219</wsse:KeyIdentifier> </wsse:SecurityTokenReference> </ds:KeyInfo> </ds:Signature> </wsse:Security> </S:Header> I've been researching for days and cannot seem to come up with a straightforward way of doing this in WCF. The web service is running on Glassfish and is soap 1.1, I've tried using all the packaged wcf bindings but have not been able to get them to work. I started down the path of using a MessageInspector, and wrote one but then realized there must be a better way, surely WCF provides some way to insert saml 2.0 assertions. I've made the most progress writing a custom binding - i've been able to get the timestamp and signature nodes in the soap header, but cannot for the life of me figure out the saml assertion. Any ideas? public static System.ServiceModel.Channels.Binding BuildCONNECTCustomBinding() { TransportSecurityBindingElement transportSecurityBindingElement = SecurityBindingElement.CreateCertificateOverTransportBindingElement(MessageSecurityVersion.WSSecurity10WSTrustFebruary2005WSSecureConversationFebruary2005WSSecurityPolicy11BasicSecurityProfile10); TextMessageEncodingBindingElement textMessageEncodingBindingElement = new TextMessageEncodingBindingElement(MessageVersion.Soap11WSAddressing10, System.Text.Encoding.UTF8); HttpsTransportBindingElement httpsTransportBindingElement = new HttpsTransportBindingElement(); SecurityTokenReferenceType securityTokenReference = new SecurityTokenReferenceType(); BindingElementCollection bindingElementCollection = new BindingElementCollection(); bindingElementCollection.Add(transportSecurityBindingElement); bindingElementCollection.Add(textMessageEncodingBindingElement); bindingElementCollection.Add(httpsTransportBindingElement); CustomBinding cb = new CustomBinding(bindingElementCollection); cb.CreateBindingElements(); return cb; }

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