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  • Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design

    - by SeanMcAlinden
    Creating a dynamic proxy generator – Part 1 – Creating the Assembly builder, Module builder and caching mechanism For the latest code go to http://rapidioc.codeplex.com/ Before getting too involved in generating the proxy, I thought it would be worth while going through the intended design, this is important as the next step is to start creating the constructors for the proxy. Each proxy derives from a specified type The proxy has a corresponding constructor for each of the base type constructors The proxy has overrides for all methods and properties marked as Virtual on the base type For each overridden method, there is also a private method whose sole job is to call the base method. For each overridden method, a delegate is created whose sole job is to call the private method that calls the base method. The following class diagram shows the main classes and interfaces involved in the interception process. I’ll go through each of them to explain their place in the overall proxy.   IProxy Interface The proxy implements the IProxy interface for the sole purpose of adding custom interceptors. This allows the created proxy interface to be cast as an IProxy and then simply add Interceptors by calling it’s AddInterceptor method. This is done internally within the proxy building process so the consumer of the API doesn’t need knowledge of this. IInterceptor Interface The IInterceptor interface has one method: Handle. The handle method accepts a IMethodInvocation parameter which contains methods and data for handling method interception. Multiple classes that implement this interface can be added to the proxy. Each method override in the proxy calls the handle method rather than simply calling the base method. How the proxy fully works will be explained in the next section MethodInvocation. IMethodInvocation Interface & MethodInvocation class The MethodInvocation will contain one main method and multiple helper properties. Continue Method The method Continue() has two functions hidden away from the consumer. When Continue is called, if there are multiple Interceptors, the next Interceptors Handle method is called. If all Interceptors Handle methods have been called, the Continue method then calls the base class method. Properties The MethodInvocation will contain multiple helper properties including at least the following: Method Name (Read Only) Method Arguments (Read and Write) Method Argument Types (Read Only) Method Result (Read and Write) – this property remains null if the method return type is void Target Object (Read Only) Return Type (Read Only) DefaultInterceptor class The DefaultInterceptor class is a simple class that implements the IInterceptor interface. Here is the code: DefaultInterceptor namespace Rapid.DynamicProxy.Interception {     /// <summary>     /// Default interceptor for the proxy.     /// </summary>     /// <typeparam name="TBase">The base type.</typeparam>     public class DefaultInterceptor<TBase> : IInterceptor<TBase> where TBase : class     {         /// <summary>         /// Handles the specified method invocation.         /// </summary>         /// <param name="methodInvocation">The method invocation.</param>         public void Handle(IMethodInvocation<TBase> methodInvocation)         {             methodInvocation.Continue();         }     } } This is automatically created in the proxy and is the first interceptor that each method override calls. It’s sole function is to ensure that if no interceptors have been added, the base method is still called. Custom Interceptor Example A consumer of the Rapid.DynamicProxy API could create an interceptor for logging when the FirstName property of the User class is set. Just for illustration, I have also wrapped a transaction around the methodInvocation.Coninue() method. This means that any overriden methods within the user class will run within a transaction scope. MyInterceptor public class MyInterceptor : IInterceptor<User<int, IRepository>> {     public void Handle(IMethodInvocation<User<int, IRepository>> methodInvocation)     {         if (methodInvocation.Name == "set_FirstName")         {             Logger.Log("First name seting to: " + methodInvocation.Arguments[0]);         }         using (TransactionScope scope = new TransactionScope())         {             methodInvocation.Continue();         }         if (methodInvocation.Name == "set_FirstName")         {             Logger.Log("First name has been set to: " + methodInvocation.Arguments[0]);         }     } } Overridden Method Example To show a taster of what the overridden methods on the proxy would look like, the setter method for the property FirstName used in the above example would look something similar to the following (this is not real code but will look similar): set_FirstName public override void set_FirstName(string value) {     set_FirstNameBaseMethodDelegate callBase =         new set_FirstNameBaseMethodDelegate(this.set_FirstNameProxyGetBaseMethod);     object[] arguments = new object[] { value };     IMethodInvocation<User<IRepository>> methodInvocation =         new MethodInvocation<User<IRepository>>(this, callBase, "set_FirstName", arguments, interceptors);          this.Interceptors[0].Handle(methodInvocation); } As you can see, a delegate instance is created which calls to a private method on the class, the private method calls the base method and would look like the following: calls base setter private void set_FirstNameProxyGetBaseMethod(string value) {     base.set_FirstName(value); } The delegate is invoked when methodInvocation.Continue() is called within an interceptor. The set_FirstName parameters are loaded into an object array. The current instance, delegate, method name and method arguments are passed into the methodInvocation constructor (there will be more data not illustrated here passed in when created including method info, return types, argument types etc.) The DefaultInterceptor’s Handle method is called with the methodInvocation instance as it’s parameter. Obviously methods can have return values, ref and out parameters etc. in these cases the generated method override body will be slightly different from above. I’ll go into more detail on these aspects as we build them. Conclusion I hope this has been useful, I can’t guarantee that the proxy will look exactly like the above, but at the moment, this is pretty much what I intend to do. Always worth downloading the code at http://rapidioc.codeplex.com/ to see the latest. There will also be some tests that you can debug through to help see what’s going on. Cheers, Sean.

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  • Rendering ASP.NET Script References into the Html Header

    - by Rick Strahl
    One thing that I’ve come to appreciate in control development in ASP.NET that use JavaScript is the ability to have more control over script and script include placement than ASP.NET provides natively. Specifically in ASP.NET you can use either the ClientScriptManager or ScriptManager to embed scripts and script references into pages via code. This works reasonably well, but the script references that get generated are generated into the HTML body and there’s very little operational control for placement of scripts. If you have multiple controls or several of the same control that need to place the same scripts onto the page it’s not difficult to end up with scripts that render in the wrong order and stop working correctly. This is especially critical if you load script libraries with dependencies either via resources or even if you are rendering referenced to CDN resources. Natively ASP.NET provides a host of methods that help embedding scripts into the page via either Page.ClientScript or the ASP.NET ScriptManager control (both with slightly different syntax): RegisterClientScriptBlock Renders a script block at the top of the HTML body and should be used for embedding callable functions/classes. RegisterStartupScript Renders a script block just prior to the </form> tag and should be used to for embedding code that should execute when the page is first loaded. Not recommended – use jQuery.ready() or equivalent load time routines. RegisterClientScriptInclude Embeds a reference to a script from a url into the page. RegisterClientScriptResource Embeds a reference to a Script from a resource file generating a long resource file string All 4 of these methods render their <script> tags into the HTML body. The script blocks give you a little bit of control by having a ‘top’ and ‘bottom’ of the document location which gives you some flexibility over script placement and precedence. Script includes and resource url unfortunately do not even get that much control – references are simply rendered into the page in the order of declaration. The ASP.NET ScriptManager control facilitates this task a little bit with the abililty to specify scripts in code and the ability to programmatically check what scripts have already been registered, but it doesn’t provide any more control over the script rendering process itself. Further the ScriptManager is a bear to deal with generically because generic code has to always check and see if it is actually present. Some time ago I posted a ClientScriptProxy class that helps with managing the latter process of sending script references either to ClientScript or ScriptManager if it’s available. Since I last posted about this there have been a number of improvements in this API, one of which is the ability to control placement of scripts and script includes in the page which I think is rather important and a missing feature in the ASP.NET native functionality. Handling ScriptRenderModes One of the big enhancements that I’ve come to rely on is the ability of the various script rendering functions described above to support rendering in multiple locations: /// <summary> /// Determines how scripts are included into the page /// </summary> public enum ScriptRenderModes { /// <summary> /// Inherits the setting from the control or from the ClientScript.DefaultScriptRenderMode /// </summary> Inherit, /// Renders the script include at the location of the control /// </summary> Inline, /// <summary> /// Renders the script include into the bottom of the header of the page /// </summary> Header, /// <summary> /// Renders the script include into the top of the header of the page /// </summary> HeaderTop, /// <summary> /// Uses ClientScript or ScriptManager to embed the script include to /// provide standard ASP.NET style rendering in the HTML body. /// </summary> Script, /// <summary> /// Renders script at the bottom of the page before the last Page.Controls /// literal control. Note this may result in unexpected behavior /// if /body and /html are not the last thing in the markup page. /// </summary> BottomOfPage } This enum is then applied to the various Register functions to allow more control over where scripts actually show up. Why is this useful? For me I often render scripts out of control resources and these scripts often include things like a JavaScript Library (jquery) and a few plug-ins. The order in which these can be loaded is critical so that jQuery.js always loads before any plug-in for example. Typically I end up with a general script layout like this: Core Libraries- HeaderTop Plug-ins: Header ScriptBlocks: Header or Script depending on other dependencies There’s also an option to render scripts and CSS at the very bottom of the page before the last Page control on the page which can be useful for speeding up page load when lots of scripts are loaded. The API syntax of the ClientScriptProxy methods is closely compatible with ScriptManager’s using static methods and control references to gain access to the page and embedding scripts. For example, to render some script into the current page in the header: // Create script block in header ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function", "function helloWorld() { alert('hello'); }", true, ScriptRenderModes.Header); // Same again - shouldn't be rendered because it's the same id ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function", "function helloWorld() { alert('hello'); }", true, ScriptRenderModes.Header); // Create a second script block in header ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function2", "function helloWorld2() { alert('hello2'); }", true, ScriptRenderModes.Header); // This just calls ClientScript and renders into bottom of document ClientScriptProxy.Current.RegisterStartupScript(this,typeof(ControlResources), "call_hello", "helloWorld();helloWorld2();", true); which generates: <html xmlns="http://www.w3.org/1999/xhtml" > <head><title> </title> <script type="text/javascript"> function helloWorld() { alert('hello'); } </script> <script type="text/javascript"> function helloWorld2() { alert('hello2'); } </script> </head> <body> … <script type="text/javascript"> //<![CDATA[ helloWorld();helloWorld2();//]]> </script> </form> </body> </html> Note that the scripts are generated into the header rather than the body except for the last script block which is the call to RegisterStartupScript. In general I wouldn’t recommend using RegisterStartupScript – ever. It’s a much better practice to use a script base load event to handle ‘startup’ code that should fire when the page first loads. So instead of the code above I’d actually recommend doing: ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "call_hello", "$().ready( function() { alert('hello2'); });", true, ScriptRenderModes.Header); assuming you’re using jQuery on the page. For script includes from a Url the following demonstrates how to embed scripts into the header. This example injects a jQuery and jQuery.UI script reference from the Google CDN then checks each with a script block to ensure that it has loaded and if not loads it from a server local location: // load jquery from CDN ClientScriptProxy.Current.RegisterClientScriptInclude(this, typeof(ControlResources), "http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js", ScriptRenderModes.HeaderTop); // check if jquery loaded - if it didn't we're not online string scriptCheck = @"if (typeof jQuery != 'object') document.write(unescape(""%3Cscript src='{0}' type='text/javascript'%3E%3C/script%3E""));"; string jQueryUrl = ClientScriptProxy.Current.GetWebResourceUrl(this, typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "jquery_register", string.Format(scriptCheck,jQueryUrl),true, ScriptRenderModes.HeaderTop); // Load jquery-ui from cdn ClientScriptProxy.Current.RegisterClientScriptInclude(this, typeof(ControlResources), "http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/jquery-ui.min.js", ScriptRenderModes.Header); // check if we need to load from local string jQueryUiUrl = ResolveUrl("~/scripts/jquery-ui-custom.min.js"); ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "jqueryui_register", string.Format(scriptCheck, jQueryUiUrl), true, ScriptRenderModes.Header); // Create script block in header ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function", "$().ready( function() { alert('hello'); });", true, ScriptRenderModes.Header); which in turn generates this HTML: <html xmlns="http://www.w3.org/1999/xhtml" > <head> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> if (typeof jQuery != 'object') document.write(unescape("%3Cscript src='/WestWindWebToolkitWeb/WebResource.axd?d=DIykvYhJ_oXCr-TA_dr35i4AayJoV1mgnQAQGPaZsoPM2LCdvoD3cIsRRitHKlKJfV5K_jQvylK7tsqO3lQIFw2&t=633979863959332352' type='text/javascript'%3E%3C/script%3E")); </script> <title> </title> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/jquery-ui.min.js" type="text/javascript"></script> <script type="text/javascript"> if (typeof jQuery != 'object') document.write(unescape("%3Cscript src='/WestWindWebToolkitWeb/scripts/jquery-ui-custom.min.js' type='text/javascript'%3E%3C/script%3E")); </script> <script type="text/javascript"> $().ready(function() { alert('hello'); }); </script> </head> <body> …</body> </html> As you can see there’s a bit more control in this process as you can inject both script includes and script blocks into the document at the top or bottom of the header, plus if necessary at the usual body locations. This is quite useful especially if you create custom server controls that interoperate with script and have certain dependencies. The above is a good example of a useful switchable routine where you can switch where scripts load from by default – the above pulls from Google CDN but a configuration switch may automatically switch to pull from the local development copies if your doing development for example. How does it work? As mentioned the ClientScriptProxy object mimicks many of the ScriptManager script related methods and so provides close API compatibility with it although it contains many additional overloads that enhance functionality. It does however work against ScriptManager if it’s available on the page, or Page.ClientScript if it’s not so it provides a single unified frontend to script access. There are however many overloads of the original SM methods like the above to provide additional functionality. The implementation of script header rendering is pretty straight forward – as long as a server header (ie. it has to have runat=”server” set) is available. Otherwise these routines fall back to using the default document level insertions of ScriptManager/ClientScript. Given that there is a server header it’s relatively easy to generate the script tags and code and append them to the header either at the top or bottom. I suspect Microsoft didn’t provide header rendering functionality precisely because a runat=”server” header is not required by ASP.NET so behavior would be slightly unpredictable. That’s not really a problem for a custom implementation however. Here’s the RegisterClientScriptBlock implementation that takes a ScriptRenderModes parameter to allow header rendering: /// <summary> /// Renders client script block with the option of rendering the script block in /// the Html header /// /// For this to work Header must be defined as runat="server" /// </summary> /// <param name="control">any control that instance typically page</param> /// <param name="type">Type that identifies this rendering</param> /// <param name="key">unique script block id</param> /// <param name="script">The script code to render</param> /// <param name="addScriptTags">Ignored for header rendering used for all other insertions</param> /// <param name="renderMode">Where the block is rendered</param> public void RegisterClientScriptBlock(Control control, Type type, string key, string script, bool addScriptTags, ScriptRenderModes renderMode) { if (renderMode == ScriptRenderModes.Inherit) renderMode = DefaultScriptRenderMode; if (control.Page.Header == null || renderMode != ScriptRenderModes.HeaderTop && renderMode != ScriptRenderModes.Header && renderMode != ScriptRenderModes.BottomOfPage) { RegisterClientScriptBlock(control, type, key, script, addScriptTags); return; } // No dupes - ref script include only once const string identifier = "scriptblock_"; if (HttpContext.Current.Items.Contains(identifier + key)) return; HttpContext.Current.Items.Add(identifier + key, string.Empty); StringBuilder sb = new StringBuilder(); // Embed in header sb.AppendLine("\r\n<script type=\"text/javascript\">"); sb.AppendLine(script); sb.AppendLine("</script>"); int? index = HttpContext.Current.Items["__ScriptResourceIndex"] as int?; if (index == null) index = 0; if (renderMode == ScriptRenderModes.HeaderTop) { control.Page.Header.Controls.AddAt(index.Value, new LiteralControl(sb.ToString())); index++; } else if(renderMode == ScriptRenderModes.Header) control.Page.Header.Controls.Add(new LiteralControl(sb.ToString())); else if (renderMode == ScriptRenderModes.BottomOfPage) control.Page.Controls.AddAt(control.Page.Controls.Count-1,new LiteralControl(sb.ToString())); HttpContext.Current.Items["__ScriptResourceIndex"] = index; } Note that the routine has to keep track of items inserted by id so that if the same item is added again with the same key it won’t generate two script entries. Additionally the code has to keep track of how many insertions have been made at the top of the document so that entries are added in the proper order. The RegisterScriptInclude method is similar but there’s some additional logic in here to deal with script file references and ClientScriptProxy’s (optional) custom resource handler that provides script compression /// <summary> /// Registers a client script reference into the page with the option to specify /// the script location in the page /// </summary> /// <param name="control">Any control instance - typically page</param> /// <param name="type">Type that acts as qualifier (uniqueness)</param> /// <param name="url">the Url to the script resource</param> /// <param name="ScriptRenderModes">Determines where the script is rendered</param> public void RegisterClientScriptInclude(Control control, Type type, string url, ScriptRenderModes renderMode) { const string STR_ScriptResourceIndex = "__ScriptResourceIndex"; if (string.IsNullOrEmpty(url)) return; if (renderMode == ScriptRenderModes.Inherit) renderMode = DefaultScriptRenderMode; // Extract just the script filename string fileId = null; // Check resource IDs and try to match to mapped file resources // Used to allow scripts not to be loaded more than once whether // embedded manually (script tag) or via resources with ClientScriptProxy if (url.Contains(".axd?r=")) { string res = HttpUtility.UrlDecode( StringUtils.ExtractString(url, "?r=", "&", false, true) ); foreach (ScriptResourceAlias item in ScriptResourceAliases) { if (item.Resource == res) { fileId = item.Alias + ".js"; break; } } if (fileId == null) fileId = url.ToLower(); } else fileId = Path.GetFileName(url).ToLower(); // No dupes - ref script include only once const string identifier = "script_"; if (HttpContext.Current.Items.Contains( identifier + fileId ) ) return; HttpContext.Current.Items.Add(identifier + fileId, string.Empty); // just use script manager or ClientScriptManager if (control.Page.Header == null || renderMode == ScriptRenderModes.Script || renderMode == ScriptRenderModes.Inline) { RegisterClientScriptInclude(control, type,url, url); return; } // Retrieve script index in header int? index = HttpContext.Current.Items[STR_ScriptResourceIndex] as int?; if (index == null) index = 0; StringBuilder sb = new StringBuilder(256); url = WebUtils.ResolveUrl(url); // Embed in header sb.AppendLine("\r\n<script src=\"" + url + "\" type=\"text/javascript\"></script>"); if (renderMode == ScriptRenderModes.HeaderTop) { control.Page.Header.Controls.AddAt(index.Value, new LiteralControl(sb.ToString())); index++; } else if (renderMode == ScriptRenderModes.Header) control.Page.Header.Controls.Add(new LiteralControl(sb.ToString())); else if (renderMode == ScriptRenderModes.BottomOfPage) control.Page.Controls.AddAt(control.Page.Controls.Count-1, new LiteralControl(sb.ToString())); HttpContext.Current.Items[STR_ScriptResourceIndex] = index; } There’s a little more code here that deals with cleaning up the passed in Url and also some custom handling of script resources that run through the ScriptCompressionModule – any script resources loaded in this fashion are automatically cached based on the resource id. Raw urls extract just the filename from the URL and cache based on that. All of this to avoid doubling up of scripts if called multiple times by multiple instances of the same control for example or several controls that all load the same resources/includes. Finally RegisterClientScriptResource utilizes the previous method to wrap the WebResourceUrl as well as some custom functionality for the resource compression module: /// <summary> /// Returns a WebResource or ScriptResource URL for script resources that are to be /// embedded as script includes. /// </summary> /// <param name="control">Any control</param> /// <param name="type">A type in assembly where resources are located</param> /// <param name="resourceName">Name of the resource to load</param> /// <param name="renderMode">Determines where in the document the link is rendered</param> public void RegisterClientScriptResource(Control control, Type type, string resourceName, ScriptRenderModes renderMode) { string resourceUrl = GetClientScriptResourceUrl(control, type, resourceName); RegisterClientScriptInclude(control, type, resourceUrl, renderMode); } /// <summary> /// Works like GetWebResourceUrl but can be used with javascript resources /// to allow using of resource compression (if the module is loaded). /// </summary> /// <param name="control"></param> /// <param name="type"></param> /// <param name="resourceName"></param> /// <returns></returns> public string GetClientScriptResourceUrl(Control control, Type type, string resourceName) { #if IncludeScriptCompressionModuleSupport // If wwScriptCompression Module through Web.config is loaded use it to compress // script resources by using wcSC.axd Url the module intercepts if (ScriptCompressionModule.ScriptCompressionModuleActive) { string url = "~/wwSC.axd?r=" + HttpUtility.UrlEncode(resourceName); if (type.Assembly != GetType().Assembly) url += "&t=" + HttpUtility.UrlEncode(type.FullName); return WebUtils.ResolveUrl(url); } #endif return control.Page.ClientScript.GetWebResourceUrl(type, resourceName); } This code merely retrieves the resource URL and then simply calls back to RegisterClientScriptInclude with the URL to be embedded which means there’s nothing specific to deal with other than the custom compression module logic which is nice and easy. What else is there in ClientScriptProxy? ClientscriptProxy also provides a few other useful services beyond what I’ve already covered here: Transparent ScriptManager and ClientScript calls ClientScriptProxy includes a host of routines that help figure out whether a script manager is available or not and all functions in this class call the appropriate object – ScriptManager or ClientScript – that is available in the current page to ensure that scripts get embedded into pages properly. This is especially useful for control development where controls have no control over the scripting environment in place on the page. RegisterCssLink and RegisterCssResource Much like the script embedding functions these two methods allow embedding of CSS links. CSS links are appended to the header or to a form declared with runat=”server”. LoadControlScript Is a high level resource loading routine that can be used to easily switch between different script linking modes. It supports loading from a WebResource, a url or not loading anything at all. This is very useful if you build controls that deal with specification of resource urls/ids in a standard way. Check out the full Code You can check out the full code to the ClientScriptProxyClass here: ClientScriptProxy.cs ClientScriptProxy Documentation (class reference) Note that the ClientScriptProxy has a few dependencies in the West Wind Web Toolkit of which it is part of. ControlResources holds a few standard constants and script resource links and the ScriptCompressionModule which is referenced in a few of the script inclusion methods. There’s also another useful ScriptContainer companion control  to the ClientScriptProxy that allows scripts to be placed onto the page’s markup including the ability to specify the script location and script minification options. You can find all the dependencies in the West Wind Web Toolkit repository: West Wind Web Toolkit Repository West Wind Web Toolkit Home Page© Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  JavaScript  

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  • SQLAuthority News – SQL Server Technical Article – The Data Loading Performance Guide

    - by pinaldave
    The white paper describes load strategies for achieving high-speed data modifications of a Microsoft SQL Server database. “Bulk Load Methods” and “Other Minimally Logged and Metadata Operations” provide an overview of two key and interrelated concepts for high-speed data loading: bulk loading and metadata operations. After this background knowledge, white paper describe how these methods can be [...]

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  • Maintaining shared service in ASP.NET MVC Application

    - by kazimanzurrashid
    Depending on the application sometimes we have to maintain some shared service throughout our application. Let’s say you are developing a multi-blog supported blog engine where both the controller and view must know the currently visiting blog, it’s setting , user information and url generation service. In this post, I will show you how you can handle this kind of case in most convenient way. First, let see the most basic way, we can create our PostController in the following way: public class PostController : Controller { public PostController(dependencies...) { } public ActionResult Index(string blogName, int? page) { BlogInfo blog = blogSerivce.FindByName(blogName); if (blog == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindPublished(blog.Id, PagingCalculator.StartIndex(page, blog.PostPerPage), blog.PostPerPage); int count = postService.GetPublishedCount(blog.Id); UserInfo user = null; if (HttpContext.User.Identity.IsAuthenticated) { user = userService.FindByName(HttpContext.User.Identity.Name); } return View(new IndexViewModel(urlResolver, user, blog, posts, count, page)); } public ActionResult Archive(string blogName, int? page, ArchiveDate archiveDate) { BlogInfo blog = blogSerivce.FindByName(blogName); if (blog == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindArchived(blog.Id, archiveDate, PagingCalculator.StartIndex(page, blog.PostPerPage), blog.PostPerPage); int count = postService.GetArchivedCount(blog.Id, archiveDate); UserInfo user = null; if (HttpContext.User.Identity.IsAuthenticated) { user = userService.FindByName(HttpContext.User.Identity.Name); } return View(new ArchiveViewModel(urlResolver, user, blog, posts, count, page, achiveDate)); } public ActionResult Tag(string blogName, string tagSlug, int? page) { BlogInfo blog = blogSerivce.FindByName(blogName); if (blog == null) { return new NotFoundResult(); } TagInfo tag = tagService.FindBySlug(blog.Id, tagSlug); if (tag == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindPublishedByTag(blog.Id, tag.Id, PagingCalculator.StartIndex(page, blog.PostPerPage), blog.PostPerPage); int count = postService.GetPublishedCountByTag(tag.Id); UserInfo user = null; if (HttpContext.User.Identity.IsAuthenticated) { user = userService.FindByName(HttpContext.User.Identity.Name); } return View(new TagViewModel(urlResolver, user, blog, posts, count, page, tag)); } } As you can see the above code heavily depends upon the current blog and the blog retrieval code is duplicated in all of the action methods, once the blog is retrieved the same blog is passed in the view model. Other than the blog the view also needs the current user and url resolver to render it properly. One way to remove the duplicate blog retrieval code is to create a custom model binder which converts the blog from a blog name and use the blog a parameter in the action methods instead of the string blog name, but it only helps the first half in the above scenario, the action methods still have to pass the blog, user and url resolver etc in the view model. Now lets try to improve the the above code, first lets create a new class which would contain the shared services, lets name it as BlogContext: public class BlogContext { public BlogInfo Blog { get; set; } public UserInfo User { get; set; } public IUrlResolver UrlResolver { get; set; } } Next, we will create an interface, IContextAwareService: public interface IContextAwareService { BlogContext Context { get; set; } } The idea is, whoever needs these shared services needs to implement this interface, in our case both the controller and the view model, now we will create an action filter which will be responsible for populating the context: public class PopulateBlogContextAttribute : FilterAttribute, IActionFilter { private static string blogNameRouteParameter = "blogName"; private readonly IBlogService blogService; private readonly IUserService userService; private readonly BlogContext context; public PopulateBlogContextAttribute(IBlogService blogService, IUserService userService, IUrlResolver urlResolver) { Invariant.IsNotNull(blogService, "blogService"); Invariant.IsNotNull(userService, "userService"); Invariant.IsNotNull(urlResolver, "urlResolver"); this.blogService = blogService; this.userService = userService; context = new BlogContext { UrlResolver = urlResolver }; } public static string BlogNameRouteParameter { [DebuggerStepThrough] get { return blogNameRouteParameter; } [DebuggerStepThrough] set { blogNameRouteParameter = value; } } public void OnActionExecuting(ActionExecutingContext filterContext) { string blogName = (string) filterContext.Controller.ValueProvider.GetValue(BlogNameRouteParameter).ConvertTo(typeof(string), Culture.Current); if (!string.IsNullOrWhiteSpace(blogName)) { context.Blog = blogService.FindByName(blogName); } if (context.Blog == null) { filterContext.Result = new NotFoundResult(); return; } if (filterContext.HttpContext.User.Identity.IsAuthenticated) { context.User = userService.FindByName(filterContext.HttpContext.User.Identity.Name); } IContextAwareService controller = filterContext.Controller as IContextAwareService; if (controller != null) { controller.Context = context; } } public void OnActionExecuted(ActionExecutedContext filterContext) { Invariant.IsNotNull(filterContext, "filterContext"); if ((filterContext.Exception == null) || filterContext.ExceptionHandled) { IContextAwareService model = filterContext.Controller.ViewData.Model as IContextAwareService; if (model != null) { model.Context = context; } } } } As you can see we are populating the context in the OnActionExecuting, which executes just before the controllers action methods executes, so by the time our action methods executes the context is already populated, next we are are assigning the same context in the view model in OnActionExecuted method which executes just after we set the  model and return the view in our action methods. Now, lets change the view models so that it implements this interface: public class IndexViewModel : IContextAwareService { // More Codes } public class ArchiveViewModel : IContextAwareService { // More Codes } public class TagViewModel : IContextAwareService { // More Codes } and the controller: public class PostController : Controller, IContextAwareService { public PostController(dependencies...) { } public BlogContext Context { get; set; } public ActionResult Index(int? page) { IEnumerable<PostInfo> posts = postService.FindPublished(Context.Blog.Id, PagingCalculator.StartIndex(page, Context.Blog.PostPerPage), Context.Blog.PostPerPage); int count = postService.GetPublishedCount(Context.Blog.Id); return View(new IndexViewModel(posts, count, page)); } public ActionResult Archive(int? page, ArchiveDate archiveDate) { IEnumerable<PostInfo> posts = postService.FindArchived(Context.Blog.Id, archiveDate, PagingCalculator.StartIndex(page, Context.Blog.PostPerPage), Context.Blog.PostPerPage); int count = postService.GetArchivedCount(Context.Blog.Id, archiveDate); return View(new ArchiveViewModel(posts, count, page, achiveDate)); } public ActionResult Tag(string blogName, string tagSlug, int? page) { TagInfo tag = tagService.FindBySlug(Context.Blog.Id, tagSlug); if (tag == null) { return new NotFoundResult(); } IEnumerable<PostInfo> posts = postService.FindPublishedByTag(Context.Blog.Id, tag.Id, PagingCalculator.StartIndex(page, Context.Blog.PostPerPage), Context.Blog.PostPerPage); int count = postService.GetPublishedCountByTag(tag.Id); return View(new TagViewModel(posts, count, page, tag)); } } Now, the last thing where we have to glue everything, I will be using the AspNetMvcExtensibility to register the action filter (as there is no better way to inject the dependencies in action filters). public class RegisterFilters : RegisterFiltersBase { private static readonly Type controllerType = typeof(Controller); private static readonly Type contextAwareType = typeof(IContextAwareService); protected override void Register(IFilterRegistry registry) { TypeCatalog controllers = new TypeCatalogBuilder() .Add(GetType().Assembly) .Include(type => controllerType.IsAssignableFrom(type) && contextAwareType.IsAssignableFrom(type)); registry.Register<PopulateBlogContextAttribute>(controllers); } } Thoughts and Comments?

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  • Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 1

    - by shiju
    In this post, I will demonstrate web application development using ASP. NET MVC 3, Razor and EF code First. This post will also cover Dependency Injection using Unity 2.0 and generic Repository and Unit of Work for EF Code First. The following frameworks will be used for this step by step tutorial. ASP.NET MVC 3 EF Code First CTP 5 Unity 2.0 Define Domain Model Let’s create domain model for our simple web application Category class public class Category {     public int CategoryId { get; set; }     [Required(ErrorMessage = "Name Required")]     [StringLength(25, ErrorMessage = "Must be less than 25 characters")]     public string Name { get; set;}     public string Description { get; set; }     public virtual ICollection<Expense> Expenses { get; set; } }   Expense class public class Expense {             public int ExpenseId { get; set; }            public string  Transaction { get; set; }     public DateTime Date { get; set; }     public double Amount { get; set; }     public int CategoryId { get; set; }     public virtual Category Category { get; set; } } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. In this post, we will be focusing on CRUD operations for the entity Category and will be working on the Expense entity with a View Model object in the later post. And the source code for this application will be refactored over time. The above entities are very simple POCO (Plain Old CLR Object) classes and the entity Category is decorated with validation attributes in the System.ComponentModel.DataAnnotations namespace. Now we want to use these entities for defining model objects for the Entity Framework 4. Using the Code First approach of Entity Framework, we can first define the entities by simply writing POCO classes without any coupling with any API or database library. This approach lets you focus on domain model which will enable Domain-Driven Development for applications. EF code first support is currently enabled with a separate API that is runs on top of the Entity Framework 4. EF Code First is reached CTP 5 when I am writing this article. Creating Context Class for Entity Framework We have created our domain model and let’s create a class in order to working with Entity Framework Code First. For this, you have to download EF Code First CTP 5 and add reference to the assembly EntitFramework.dll. You can also use NuGet to download add reference to EEF Code First.    public class MyFinanceContext : DbContext {     public MyFinanceContext() : base("MyFinance") { }     public DbSet<Category> Categories { get; set; }     public DbSet<Expense> Expenses { get; set; }         }   The above class MyFinanceContext is derived from DbContext that can connect your model classes to a database. The MyFinanceContext class is mapping our Category and Expense class into database tables Categories and Expenses using DbSet<TEntity> where TEntity is any POCO class. When we are running the application at first time, it will automatically create the database. EF code-first look for a connection string in web.config or app.config that has the same name as the dbcontext class. If it is not find any connection string with the convention, it will automatically create database in local SQL Express database by default and the name of the database will be same name as the dbcontext class. You can also define the name of database in constructor of the the dbcontext class. Unlike NHibernate, we don’t have to use any XML based mapping files or Fluent interface for mapping between our model and database. The model classes of Code First are working on the basis of conventions and we can also use a fluent API to refine our model. The convention for primary key is ‘Id’ or ‘<class name>Id’.  If primary key properties are detected with type ‘int’, ‘long’ or ‘short’, they will automatically registered as identity columns in the database by default. Primary key detection is not case sensitive. We can define our model classes with validation attributes in the System.ComponentModel.DataAnnotations namespace and it automatically enforces validation rules when a model object is updated or saved. Generic Repository for EF Code First We have created model classes and dbcontext class. Now we have to create generic repository pattern for data persistence with EF code first. If you don’t know about the repository pattern, checkout Martin Fowler’s article on Repository Let’s create a generic repository to working with DbContext and DbSet generics. public interface IRepository<T> where T : class     {         void Add(T entity);         void Delete(T entity);         T GetById(long Id);         IEnumerable<T> All();     }   RepositoryBasse – Generic Repository class public abstract class RepositoryBase<T> where T : class { private MyFinanceContext database; private readonly IDbSet<T> dbset; protected RepositoryBase(IDatabaseFactory databaseFactory) {     DatabaseFactory = databaseFactory;     dbset = Database.Set<T>(); }   protected IDatabaseFactory DatabaseFactory {     get; private set; }   protected MyFinanceContext Database {     get { return database ?? (database = DatabaseFactory.Get()); } } public virtual void Add(T entity) {     dbset.Add(entity);            }        public virtual void Delete(T entity) {     dbset.Remove(entity); }   public virtual T GetById(long id) {     return dbset.Find(id); }   public virtual IEnumerable<T> All() {     return dbset.ToList(); } }   DatabaseFactory class public class DatabaseFactory : Disposable, IDatabaseFactory {     private MyFinanceContext database;     public MyFinanceContext Get()     {         return database ?? (database = new MyFinanceContext());     }     protected override void DisposeCore()     {         if (database != null)             database.Dispose();     } } Unit of Work If you are new to Unit of Work pattern, checkout Fowler’s article on Unit of Work . According to Martin Fowler, the Unit of Work pattern "maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency problems." Let’s create a class for handling Unit of Work   public interface IUnitOfWork {     void Commit(); }   UniOfWork class public class UnitOfWork : IUnitOfWork {     private readonly IDatabaseFactory databaseFactory;     private MyFinanceContext dataContext;       public UnitOfWork(IDatabaseFactory databaseFactory)     {         this.databaseFactory = databaseFactory;     }       protected MyFinanceContext DataContext     {         get { return dataContext ?? (dataContext = databaseFactory.Get()); }     }       public void Commit()     {         DataContext.Commit();     } }   The Commit method of the UnitOfWork will call the commit method of MyFinanceContext class and it will execute the SaveChanges method of DbContext class.   Repository class for Category In this post, we will be focusing on the persistence against Category entity and will working on other entities in later post. Let’s create a repository for handling CRUD operations for Category using derive from a generic Repository RepositoryBase<T>.   public class CategoryRepository: RepositoryBase<Category>, ICategoryRepository     {     public CategoryRepository(IDatabaseFactory databaseFactory)         : base(databaseFactory)         {         }                } public interface ICategoryRepository : IRepository<Category> { } If we need additional methods than generic repository for the Category, we can define in the CategoryRepository. Dependency Injection using Unity 2.0 If you are new to Inversion of Control/ Dependency Injection or Unity, please have a look on my articles at http://weblogs.asp.net/shijuvarghese/archive/tags/IoC/default.aspx. I want to create a custom lifetime manager for Unity to store container in the current HttpContext.   public class HttpContextLifetimeManager<T> : LifetimeManager, IDisposable {     public override object GetValue()     {         return HttpContext.Current.Items[typeof(T).AssemblyQualifiedName];     }     public override void RemoveValue()     {         HttpContext.Current.Items.Remove(typeof(T).AssemblyQualifiedName);     }     public override void SetValue(object newValue)     {         HttpContext.Current.Items[typeof(T).AssemblyQualifiedName] = newValue;     }     public void Dispose()     {         RemoveValue();     } }   Let’s create controller factory for Unity in the ASP.NET MVC 3 application. public class UnityControllerFactory : DefaultControllerFactory { IUnityContainer container; public UnityControllerFactory(IUnityContainer container) {     this.container = container; } protected override IController GetControllerInstance(RequestContext reqContext, Type controllerType) {     IController controller;     if (controllerType == null)         throw new HttpException(                 404, String.Format(                     "The controller for path '{0}' could not be found" +     "or it does not implement IController.",                 reqContext.HttpContext.Request.Path));       if (!typeof(IController).IsAssignableFrom(controllerType))         throw new ArgumentException(                 string.Format(                     "Type requested is not a controller: {0}",                     controllerType.Name),                     "controllerType");     try     {         controller= container.Resolve(controllerType) as IController;     }     catch (Exception ex)     {         throw new InvalidOperationException(String.Format(                                 "Error resolving controller {0}",                                 controllerType.Name), ex);     }     return controller; }   }   Configure contract and concrete types in Unity Let’s configure our contract and concrete types in Unity for resolving our dependencies.   private void ConfigureUnity() {     //Create UnityContainer               IUnityContainer container = new UnityContainer()                 .RegisterType<IDatabaseFactory, DatabaseFactory>(new HttpContextLifetimeManager<IDatabaseFactory>())     .RegisterType<IUnitOfWork, UnitOfWork>(new HttpContextLifetimeManager<IUnitOfWork>())     .RegisterType<ICategoryRepository, CategoryRepository>(new HttpContextLifetimeManager<ICategoryRepository>());                 //Set container for Controller Factory                ControllerBuilder.Current.SetControllerFactory(             new UnityControllerFactory(container)); }   In the above ConfigureUnity method, we are registering our types onto Unity container with custom lifetime manager HttpContextLifetimeManager. Let’s call ConfigureUnity method in the Global.asax.cs for set controller factory for Unity and configuring the types with Unity.   protected void Application_Start() {     AreaRegistration.RegisterAllAreas();     RegisterGlobalFilters(GlobalFilters.Filters);     RegisterRoutes(RouteTable.Routes);     ConfigureUnity(); }   Developing web application using ASP.NET MVC 3 We have created our domain model for our web application and also have created repositories and configured dependencies with Unity container. Now we have to create controller classes and views for doing CRUD operations against the Category entity. Let’s create controller class for Category Category Controller   public class CategoryController : Controller {     private readonly ICategoryRepository categoryRepository;     private readonly IUnitOfWork unitOfWork;           public CategoryController(ICategoryRepository categoryRepository, IUnitOfWork unitOfWork)     {         this.categoryRepository = categoryRepository;         this.unitOfWork = unitOfWork;     }       public ActionResult Index()     {         var categories = categoryRepository.All();         return View(categories);     }     [HttpGet]     public ActionResult Edit(int id)     {         var category = categoryRepository.GetById(id);         return View(category);     }       [HttpPost]     public ActionResult Edit(int id, FormCollection collection)     {         var category = categoryRepository.GetById(id);         if (TryUpdateModel(category))         {             unitOfWork.Commit();             return RedirectToAction("Index");         }         else return View(category);                 }       [HttpGet]     public ActionResult Create()     {         var category = new Category();         return View(category);     }           [HttpPost]     public ActionResult Create(Category category)     {         if (!ModelState.IsValid)         {             return View("Create", category);         }                     categoryRepository.Add(category);         unitOfWork.Commit();         return RedirectToAction("Index");     }       [HttpPost]     public ActionResult Delete(int  id)     {         var category = categoryRepository.GetById(id);         categoryRepository.Delete(category);         unitOfWork.Commit();         var categories = categoryRepository.All();         return PartialView("CategoryList", categories);       }        }   Creating Views in Razor Now we are going to create views in Razor for our ASP.NET MVC 3 application.  Let’s create a partial view CategoryList.cshtml for listing category information and providing link for Edit and Delete operations. CategoryList.cshtml @using MyFinance.Helpers; @using MyFinance.Domain; @model IEnumerable<Category>      <table>         <tr>         <th>Actions</th>         <th>Name</th>          <th>Description</th>         </tr>     @foreach (var item in Model) {             <tr>             <td>                 @Html.ActionLink("Edit", "Edit",new { id = item.CategoryId })                 @Ajax.ActionLink("Delete", "Delete", new { id = item.CategoryId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divCategoryList" })                           </td>             <td>                 @item.Name             </td>             <td>                 @item.Description             </td>         </tr>          }       </table>     <p>         @Html.ActionLink("Create New", "Create")     </p> The delete link is providing Ajax functionality using the Ajax.ActionLink. This will call an Ajax request for Delete action method in the CategoryCotroller class. In the Delete action method, it will return Partial View CategoryList after deleting the record. We are using CategoryList view for the Ajax functionality and also for Index view using for displaying list of category information. Let’s create Index view using partial view CategoryList  Index.chtml @model IEnumerable<MyFinance.Domain.Category> @{     ViewBag.Title = "Index"; }    <h2>Category List</h2>    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script>    <div id="divCategoryList">               @Html.Partial("CategoryList", Model) </div>   We can call the partial views using Html.Partial helper method. Now we are going to create View pages for insert and update functionality for the Category. Both view pages are sharing common user interface for entering the category information. So I want to create an EditorTemplate for the Category information. We have to create the EditorTemplate with the same name of entity object so that we can refer it on view pages using @Html.EditorFor(model => model) . So let’s create template with name Category. Let’s create view page for insert Category information   @model MyFinance.Domain.Category   @{     ViewBag.Title = "Save"; }   <h2>Create</h2>   <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>   @using (Html.BeginForm()) {     @Html.ValidationSummary(true)     <fieldset>         <legend>Category</legend>                @Html.EditorFor(model => model)               <p>             <input type="submit" value="Create" />         </p>     </fieldset> }   <div>     @Html.ActionLink("Back to List", "Index") </div> ViewStart file In Razor views, we can add a file named _viewstart.cshtml in the views directory  and this will be shared among the all views with in the Views directory. The below code in the _viewstart.cshtml, sets the Layout page for every Views in the Views folder.      @{     Layout = "~/Views/Shared/_Layout.cshtml"; }   Source Code You can download the source code from http://efmvc.codeplex.com/ . The source will be refactored on over time.   Summary In this post, we have created a simple web application using ASP.NET MVC 3 and EF Code First. We have discussed on technologies and practices such as ASP.NET MVC 3, Razor, EF Code First, Unity 2, generic Repository and Unit of Work. In my later posts, I will modify the application and will be discussed on more things. Stay tuned to my blog  for more posts on step by step application building.

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  • Do unit tests sometimes break encapsulation?

    - by user1288851
    I very often hear the following: "If you want to test private methods, you'd better put that in another class and expose it." While sometimes that's the case and we have a hiding concept inside our class, other times you end up with classes that have the same attributes (or, worst, every attribute of one class become a argument on a method in the other class) and exposes functionality that is, in fact, implementation detail. Specially on TDD, when you refactor a class with public methods out of a previous tested class, that class is now part of your interface, but has no tests to it (since you refactored it, and is a implementation detail). Now, I may be not finding an obvious better answer, but if my answer is the "correct", that means that sometimes writting unit tests can break encapsulation, and divide the same responsibility into different classes. A simple example would be testing a setter method when a getter is not actually needed for anything in the real code. Please when aswering don't provide simple answers to specific cases I may have written. Rather, try to explain more of the generic case and theoretical approach. And this is neither language specific. Thanks in advance. EDIT: The answer given by Matthew Flynn was really insightful, but didn't quite answer the question. Altough he made the fair point that you either don't test private methods or extract them because they really are other concern and responsibility (or at least that was what I could understand from his answer), I think there are situations where unit testing private methods is useful. My primary example is when you have a class that has one responsibility but the output (or input) that it gives (takes) is just to complex. For example, a hashing function. There's no good way to break a hashing function apart and mantain cohesion and encapsulation. However, testing a hashing function can be really tough, since you would need to calculate by hand (you can't use code calculation to test code calculation!) the hashing, and test multiple cases where the hash changes. In that way (and this may be a question worth of its own topic) I think private method testing is the best way to handle it. Now, I'm not sure if I should ask another question, or ask it here, but are there any better way to test such complex output (input)? OBS: Please, if you think I should ask another question on that topic, leave a comment. :)

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  • Video on Architecture and Code Quality using Visual Studio 2012&ndash;interview with Marcel de Vries and Terje Sandstrom by Adam Cogan

    - by terje
    Find the video HERE. Adam Cogan did a great Web TV interview with Marcel de Vries and myself on the topics of architecture and code quality.  It was real fun participating in this session.  Although we know each other from the MVP ALM community,  Marcel, Adam and I haven’t worked together before. It was very interesting to see how we agreed on so many terms, and how alike we where thinking.  The basics of ensuring you have a good architecture and how you could document it is one thing.  Also, the same agreement on the importance of having a high quality code base, and how we used the Visual Studio 2012 tools, and some others (NDepend for example)  to measure and ensure that the code quality was where it should be.  As the tools, methods and thinking popped up during the interview it was a lot of “Hey !  I do that too!”.  The tools are not only for “after the fact” work, but we use them during the coding.  That way the tools becomes an integrated part of our coding work, and helps us to find issues we may have overlooked.  The video has a bunch of call outs, pinpointing important things to remember. These are also listed on the corresponding web page. I haven’t seen that touch before, but really liked this way of doing it – it makes it much easier to spot the highlights.  Titus Maclaren and Raj Dhatt from SSW have done a terrific job producing this video.  And thanks to Lei Xu for doing the camera and recording job.  Thanks guys ! Also, if you are at TechEd Amsterdam 2012, go and listen to Adam Cogan in his session on “A modern architecture review: Using the new code review tools” Friday 29th, 10.15-11.30 and Marcel de Vries session on “Intellitrace, what is it and how can I use it to my benefit” Wednesday 27th, 5-6.15 The highlights points out some important practices.  I’ll elaborate on a few of them here: Add instructions on how to compile the solution.  You do this by adding a text file with instructions to the solution, and keep it under source control.  These instructions should contain what is needed on top of a standard install of Visual Studio.  I do a lot of code reviews, and more often that not, I am not even able to compile the program, because they have used some tool or library that needs to be installed.  The same applies to any new developer who enters into the team, so do this to increase your productivity when the team changes, or a team member switches computer. Don’t forget to document what you have to configure on the computer, the IIS being a common one. The more automatic you can do this, the better.  Use NuGet to get down libraries. When the text document gets more than say, half a page, with a bunch of different things to do, convert it into a powershell script instead.  The metrics warning levels.  These are very conservatively set by Microsoft.  You rarely see anything but green, and besides, you should have color scales for each of the metrics.  I have a blog post describing a more appropriate set of levels, based on both research work and industry “best practices”.  The essential limits are: Cyclomatic complexity and coupling:  Higher numbers are worse On method levels: Green :  From 0 to 10 Yellow:  From 10 to 20  (some say 15).   Acceptable, but have a look to see if there is something unneeded here. Red: From 20 to 40:   Action required, get these down. Bleeding Red: Above 40   This is the real red alert.  Immediate action!  (My invention, as people have asked what do I do when I have cyclomatic complexity of 150.  The only answer I could think of was: RUN! ) Maintainability index:  Lower numbers are worse, scale from 0 to 100. On method levels: Green:  60 to 100 Yellow:  40 – 60.    You will always have methods here too, accept the higher ones, take a look at those who are down to the lower limit.  Check up against the other metrics.) Red:  20 – 40:  Action required, fix these. Bleeding red:  Below 20.  Immediate action required. When doing metrics analysis, you should leave the generated code out.  You do this by adding attributes, unfortunately Microsoft has “forgotten” to add these to all their stuff, so you might have to add them to some of the code.  It most cases it can be done so that it is not overwritten by a new round of code generation.  Take a look a my blog post here for details on how to do that. Class level metrics might also be useful, at least for coupling and maintenance.  But it is much more difficult to set any fixed limits on those.  Any metric aggregations on higher level tend to be pretty useless, as the number of methods vary pretty much, and there are little science on what number of methods can be regarded as good or bad.  NDepend have a recommendation, but they say it may vary too.  And in these days of data binding, the number might be pretty high, as properties counts as methods.  However, if you take the worst case situations, classes with more than 20 methods are suspicious, and coupling and cyclomatic complexity go red above 20, so any classes with more than 20x20 = 400 for these measures should be checked over. In the video we mention the SOLID principles, coined by “Uncle Bob” (Richard Martin). One of them, the Dependency Inversion principle we discuss in the video.  It is important to note that this principle is NOT on whether you should use a Dependency Inversion Container or not, it is about how you design the interfaces and interactions between your classes.  The Dependency Inversion Container is just one technique which is based on this principle, but which main purpose is to isolate things you would like to change at runtime, for example if you implement a plug in architecture.  Overuse of a Dependency Inversion Container is however, NOT a good thing.  It should be used for a purpose and not as a general DI solution.  The general DI solution and thinking however is useful far beyond the DIC.   You should always “program to an abstraction”, and not to the concreteness.  We also talk a bit about the GRASP patterns, a term coined by Craig Larman in his book Applying UML and design patterns. GRASP patterns stand for General Responsibility Assignment Software Patterns and describe fundamental principles of object design and responsibility assignment.  What I find great with these patterns is that they is another way to focus on the responsibility of a class.  One of the things I most often found that is broken in software designs, is that the class lack responsibility, and as a result there are a lot of classes mucking around in the internals of the other classes.  We also discuss the term “Code Smells”.  This term was invented by Kent Beck and Martin Fowler when they worked with Fowler’s “Refactoring” book. A code smell is a set of “bad” coding practices, which are the drivers behind a corresponding set of refactorings.  Here is a good list of the smells, and their corresponding refactor patterns. See also this.

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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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  • Do I suffer from encapsulation overuse?

    - by Florenc
    I have noticed something in my code in various projects that seems like code smell to me and something bad to do, but I can't deal with it. While trying to write "clean code" I tend to over-use private methods in order to make my code easier to read. The problem is that the code is indeed cleaner but it's also more difficult to test (yeah I know I can test private methods...) and in general it seems a bad habit to me. Here's an example of a class that reads some data from a .csv file and returns a group of customers (another object with various fields and attributes). public class GroupOfCustomersImporter { //... Call fields .... public GroupOfCustomersImporter(String filePath) { this.filePath = filePath; customers = new HashSet<Customer>(); createCSVReader(); read(); constructTTRP_Instance(); } private void createCSVReader() { //.... } private void read() { //.... Reades the file and initializes the class attributes } private void readFirstLine(String[] inputLine) { //.... Method used by the read() method } private void readSecondLine(String[] inputLine) { //.... Method used by the read() method } private void readCustomerLine(String[] inputLine) { //.... Method used by the read() method } private void constructGroupOfCustomers() { //this.groupOfCustomers = new GroupOfCustomers(**attributes of the class**); } public GroupOfCustomers getConstructedGroupOfCustomers() { return this.GroupOfCustomers; } } As you can see the class has only a constructor which calls some private methods to get the job done, I know that's not a good practice not a good practice in general but I prefer to encapsulate all the functionality in the class instead of making the methods public in which case a client should work this way: GroupOfCustomersImporter importer = new GroupOfCustomersImporter(filepath) importer.createCSVReader(); read(); GroupOfCustomer group = constructGoupOfCustomerInstance(); I prefer this because I don't want to put useless lines of code in the client's side code bothering the client class with implementation details. So, Is this actually a bad habit? If yes, how can I avoid it? Please note that the above is just a simple example. Imagine the same situation happening in something a little bit more complex.

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  • Exchange server not serving mobile devices - how to troubleshoot?

    - by chickeninabiscuit
    Our exchange server has suddenly stopped serving mobile devices. Attempts to connect result in our ActiveSync server returning HTTP 500. It is serving outlook clients fine. Our server is Windows 2003 SBS 6.5 SP2 There are no abnormal events in the system log. I ran the "Exchange ActiveSync with AutoDiscover" at https://www.testexchangeconnectivity.com/ I've notice an abnormality in the exchange properties, Log File Directory shows: Access denied. Facility: Win32 ID no: 80070005 Exchange System Manager As shown in the following image: I think it may be related to a recent issue we had here: http://serverfault.com/questions/40222/windows-server-2003-suddenly-unable-to-connect-to-anything We followed a procedure to reinstall TCP/IP: http://support.microsoft.com/kb/325356 I've run the "exchange activesync" connectivity test at testexchangeconnectivity.com: Attempting to Resolve the host name mail.immersive.com.au in DNS. Host successfully Resolved Additional Details IP(s) returned: 221.133.203.229 Testing TCP Port 443 on host mail.immersive.com.au to ensure it is listening/open. The port was opened successfully. Testing SSL Certificate for validity. The certificate passed all validation requirements. Test Steps Validating certificate name Successfully validated the certificate name Additional Details Found hostname mail.immersive.com.au in Certificate Subject Common name Validating certificate trust for Windows Mobile Devices Certificate is trusted and all certificates are present in chain Additional Details Certificate is trusted for Windows Mobile 5 and Later platforms. Root = [email protected], CN=Thawte Server CA, OU=Certification Services Division, O=Thawte Consulting cc, L=Cape Town, S=Western Cape, C=ZA Testing certificate date to ensure validity Date Validation passed. The certificate is not expired. Additional Details Certificate is valid: NotBefore = 1/5/2009 4:00:00 PM, NotAfter = 1/11/2010 3:59:59 PM Testing Http Authentication Methods for URL https://mail.immersive.com.au/Microsoft-Server-Activesync/ Http Authentication Methods are correct Additional Details Found all expected authentication methods and no disallowed methods. Methods Found: Basic Attempting an Activesync session with server Errors were encountered while testing the ActiveSync session Test Steps Attempting to send OPTIONS command to server OPTIONS response was successfully received and is valid Additional Details Headers received: MicrosoftOfficeWebServer: 5.0_Pub Pragma: no-cache Public: OPTIONS, POST Allow: OPTIONS, POST MS-Server-ActiveSync: 6.5.7638.1 MS-ASProtocolVersions: 1.0,2.0,2.1,2.5 MS-ASProtocolCommands: Sync,SendMail,SmartForward,SmartReply,GetAttachment,GetHierarchy,CreateCollection,DeleteCollection,MoveCollection,FolderSync,FolderCreate,FolderDelete,FolderUpdate,MoveItems,GetItemEstimate,MeetingResponse,ResolveRecipients,ValidateCert,Provision,Search,Notify,Ping Content-Length: 0 Date: Thu, 16 Jul 2009 01:07:27 GMT Server: Microsoft-IIS/6.0 X-Powered-By: ASP.NET Attempting FolderSync command on ActiveSync session FolderSync command test failed Tell me more about this issue and how to resolve it Additional Details Exchange

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  • Interesting links week #5

    - by erwin21
    Below a list of interesting links that I found this week: Frontend: Useful jQuery Tutorials - January 2011 50 Useful CSS3 Tutorials Development: 5 Helpful DateTime Extension Methods Helpful DateTime extension methods for dealing with Time Zones SEO: 30 (New) SEO Terms You Have to Know in 2011 URL Design 6 Must Have Google Chrome SEO Extensions Interested in more interesting links follow me at twitter http://twitter.com/erwingriekspoor

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  • Looking into ASP.Net MVC 4.0 Mobile Development - part 2

    - by nikolaosk
    In this post I will be continuing my discussion on ASP.Net MVC 4.0 mobile development. You can have a look at my first post on the subject here . Make sure you read it and understand it well before you move one reading the remaining of this post. I will not be writing any code in this post. I will try to explain a few concepts related to the MVC 4.0 mobile functionality. In this post I will be looking into the Browser Overriding feature in ASP.Net MVC 4.0. By that I mean that we override the user agent for a given user session. This is very useful feature for people who visit a site through a device and they experience the mobile version of the site, but what they really want is the option to be able to switch to the desktop view. "Why they might want to do that?", you might wonder.Well first of all the users of our ASP.Net MVC 4.0 application will appreciate that they have the option to switch views while some others will think that they will enjoy more the contents of our website with the "desktop view" since the mobile device they view our site has a quite large display.  Obviously this is only one site. These are just different views that are rendered.To put it simply, browser overriding lets our application treat requests as if they were coming from a different browser rather than the one they are actually from. In order to do that programmatically we must have a look at the System.Web.WebPages namespace and the classes in it. Most specifically the class BrowserHelpers. Have a look at the picture below   In this class we see some extension methods for HttpContext class.These methods are called extensions-helpers methods and we use them to switch to one browser from another thus overriding the current/actual browser. These APIs have effect on layout,views and partial views and will not affect any other ASP.Net Request.Browser related functionality.The overridden browser is stored in a cookie. Let me explain what some of these methods do. SetOverriddenBrowser() -  let us set the user agent string to specific value GetOverriddenBrowser() -  let us get the overridden value ClearOverriddenBrowser() -  let us remove any overridden user agent for the current request   To recap, in our ASP.Net MVC 4.0 applications when our application is viewed in our mobile devices, we can have a link like "Desktop View" for all those who desperately want to see the site with in full desktop-browser version.We then can specify a browser type override. My controller class (snippet of code) that is responsible for handling the switching could be something like that. public class SwitchViewController : Controller{ public RedirectResult SwitchView(bool mobile, string returnUrl){if (Request.Browser.IsMobileDevice == mobile)HttpContext.ClearOverriddenBrowser();elseHttpContext.SetOverriddenBrowser(mobile ? BrowserOverride.Mobile : BrowserOverride.Desktop);return Redirect(returnUrl);}} Hope it helps!!!!

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  • C#/.NET Little Wonders: The Timeout static class

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. When I started the “Little Wonders” series, I really wanted to pay homage to parts of the .NET Framework that are often small but can help in big ways.  The item I have to discuss today really is a very small item in the .NET BCL, but once again I feel it can help make the intention of code much clearer and thus is worthy of note. The Problem - Magic numbers aren’t very readable or maintainable In my first Little Wonders Post (Five Little Wonders That Make Code Better) I mention the TimeSpan factory methods which, I feel, really help the readability of constructed TimeSpan instances. Just to quickly recap that discussion, ask yourself what the TimeSpan specified in each case below is 1: // Five minutes? Five Seconds? 2: var fiveWhat1 = new TimeSpan(0, 0, 5); 3: var fiveWhat2 = new TimeSpan(0, 0, 5, 0); 4: var fiveWhat3 = new TimeSpan(0, 0, 5, 0, 0); You’d think they’d all be the same unit of time, right?  After all, most overloads tend to tack additional arguments on the end.  But this is not the case with TimeSpan, where the constructor forms are:     TimeSpan(int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds); Notice how in the 4 and 5 parameter version we suddenly have the parameter days slipping in front of hours?  This can make reading constructors like those above much harder.  Fortunately, there are TimeSpan factory methods to help make your intention crystal clear: 1: // Ah! Much clearer! 2: var fiveSeconds = TimeSpan.FromSeconds(5); These are great because they remove all ambiguity from the reader!  So in short, magic numbers in constructors and methods can be ambiguous, and anything we can do to clean up the intention of the developer will make the code much easier to read and maintain. Timeout – Readable identifiers for infinite timeout values In a similar way to TimeSpan, let’s consider specifying timeouts for some of .NET’s (or our own) many methods that allow you to specify timeout periods. For example, in the TPL Task class, there is a family of Wait() methods that can take TimeSpan or int for timeouts.  Typically, if you want to specify an infinite timeout, you’d just call the version that doesn’t take a timeout parameter at all: 1: myTask.Wait(); // infinite wait But there are versions that take the int or TimeSpan for timeout as well: 1: // Wait for 100 ms 2: myTask.Wait(100); 3:  4: // Wait for 5 seconds 5: myTask.Wait(TimeSpan.FromSeconds(5); Now, if we want to specify an infinite timeout to wait on the Task, we could pass –1 (or a TimeSpan set to –1 ms), which what the .NET BCL methods with timeouts use to represent an infinite timeout: 1: // Also infinite timeouts, but harder to read/maintain 2: myTask.Wait(-1); 3: myTask.Wait(TimeSpan.FromMilliseconds(-1)); However, these are not as readable or maintainable.  If you were writing this code, you might make the mistake of thinking 0 or int.MaxValue was an infinite timeout, and you’d be incorrect.  Also, reading the code above it isn’t as clear that –1 is infinite unless you happen to know that is the specified behavior. To make the code like this easier to read and maintain, there is a static class called Timeout in the System.Threading namespace which contains definition for infinite timeouts specified as both int and TimeSpan forms: Timeout.Infinite An integer constant with a value of –1 Timeout.InfiniteTimeSpan A static readonly TimeSpan which represents –1 ms (only available in .NET 4.5+) This makes our calls to Task.Wait() (or any other calls with timeouts) much more clear: 1: // intention to wait indefinitely is quite clear now 2: myTask.Wait(Timeout.Infinite); 3: myTask.Wait(Timeout.InfiniteTimeSpan); But wait, you may say, why would we care at all?  Why not use the version of Wait() that takes no arguments?  Good question!  When you’re directly calling the method with an infinite timeout that’s what you’d most likely do, but what if you are just passing along a timeout specified by a caller from higher up?  Or perhaps storing a timeout value from a configuration file, and want to default it to infinite? For example, perhaps you are designing a communications module and want to be able to shutdown gracefully, but if you can’t gracefully finish in a specified amount of time you want to force the connection closed.  You could create a Shutdown() method in your class, and take a TimeSpan or an int for the amount of time to wait for a clean shutdown – perhaps waiting for client to acknowledge – before terminating the connection.  So, assume we had a pub/sub system with a class to broadcast messages: 1: // Some class to broadcast messages to connected clients 2: public class Broadcaster 3: { 4: // ... 5:  6: // Shutdown connection to clients, wait for ack back from clients 7: // until all acks received or timeout, whichever happens first 8: public void Shutdown(int timeout) 9: { 10: // Kick off a task here to send shutdown request to clients and wait 11: // for the task to finish below for the specified time... 12:  13: if (!shutdownTask.Wait(timeout)) 14: { 15: // If Wait() returns false, we timed out and task 16: // did not join in time. 17: } 18: } 19: } We could even add an overload to allow us to use TimeSpan instead of int, to give our callers the flexibility to specify timeouts either way: 1: // overload to allow them to specify Timeout in TimeSpan, would 2: // just call the int version passing in the TotalMilliseconds... 3: public void Shutdown(TimeSpan timeout) 4: { 5: Shutdown(timeout.TotalMilliseconds); 6: } Notice in case of this class, we don’t assume the caller wants infinite timeouts, we choose to rely on them to tell us how long to wait.  So now, if they choose an infinite timeout, they could use the –1, which is more cryptic, or use Timeout class to make the intention clear: 1: // shutdown the broadcaster, waiting until all clients ack back 2: // without timing out. 3: myBroadcaster.Shutdown(Timeout.Infinite); We could even add a default argument using the int parameter version so that specifying no arguments to Shutdown() assumes an infinite timeout: 1: // Modified original Shutdown() method to add a default of 2: // Timeout.Infinite, works because Timeout.Infinite is a compile 3: // time constant. 4: public void Shutdown(int timeout = Timeout.Infinite) 5: { 6: // same code as before 7: } Note that you can’t default the ShutDown(TimeSpan) overload with Timeout.InfiniteTimeSpan since it is not a compile-time constant.  The only acceptable default for a TimeSpan parameter would be default(TimeSpan) which is zero milliseconds, which specified no wait, not infinite wait. Summary While Timeout.Infinite and Timeout.InfiniteTimeSpan are not earth-shattering classes in terms of functionality, they do give you very handy and readable constant values that you can use in your programs to help increase readability and maintainability when specifying infinite timeouts for various timeouts in the BCL and your own applications. Technorati Tags: C#,CSharp,.NET,Little Wonders,Timeout,Task

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  • .NET Security Part 2

    - by Simon Cooper
    So, how do you create partial-trust appdomains? Where do you come across them? There are two main situations in which your assembly runs as partially-trusted using the Microsoft .NET stack: Creating a CLR assembly in SQL Server with anything other than the UNSAFE permission set. The permissions available in each permission set are given here. Loading an assembly in ASP.NET in any trust level other than Full. Information on ASP.NET trust levels can be found here. You can configure the specific permissions available to assemblies using ASP.NET policy files. Alternatively, you can create your own partially-trusted appdomain in code and directly control the permissions and the full-trust API available to the assemblies you load into the appdomain. This is the scenario I’ll be concentrating on in this post. Creating a partially-trusted appdomain There is a single overload of AppDomain.CreateDomain that allows you to specify the permissions granted to assemblies in that appdomain – this one. This is the only call that allows you to specify a PermissionSet for the domain. All the other calls simply use the permissions of the calling code. If the permissions are restricted, then the resulting appdomain is referred to as a sandboxed domain. There are three things you need to create a sandboxed domain: The specific permissions granted to all assemblies in the domain. The application base (aka working directory) of the domain. The list of assemblies that have full-trust if they are loaded into the sandboxed domain. The third item is what allows us to have a fully-trusted API that is callable by partially-trusted code. I’ll be looking at the details of this in a later post. Granting permissions to the appdomain Firstly, the permissions granted to the appdomain. This is encapsulated in a PermissionSet object, initialized either with no permissions or full-trust permissions. For sandboxed appdomains, the PermissionSet is initialized with no permissions, then you add permissions you want assemblies loaded into that appdomain to have by default: PermissionSet restrictedPerms = new PermissionSet(PermissionState.None); // all assemblies need Execution permission to run at all restrictedPerms.AddPermission( new SecurityPermission(SecurityPermissionFlag.Execution)); // grant general read access to C:\config.xml restrictedPerms.AddPermission( new FileIOPermission(FileIOPermissionAccess.Read, @"C:\config.xml")); // grant permission to perform DNS lookups restrictedPerms.AddPermission( new DnsPermission(PermissionState.Unrestricted)); It’s important to point out that the permissions granted to an appdomain, and so to all assemblies loaded into that appdomain, are usable without needing to go through any SafeCritical code (see my last post if you’re unsure what SafeCritical code is). That is, partially-trusted code loaded into an appdomain with the above permissions (and so running under the Transparent security level) is able to create and manipulate a FileStream object to read from C:\config.xml directly. It is only for operations requiring permissions that are not granted to the appdomain that partially-trusted code is required to call a SafeCritical method that then asserts the missing permissions and performs the operation safely on behalf of the partially-trusted code. The application base of the domain This is simply set as a property on an AppDomainSetup object, and is used as the default directory assemblies are loaded from: AppDomainSetup appDomainSetup = new AppDomainSetup { ApplicationBase = @"C:\temp\sandbox", }; If you’ve read the documentation around sandboxed appdomains, you’ll notice that it mentions a security hole if this parameter is set correctly. I’ll be looking at this, and other pitfalls, that will break the sandbox when using sandboxed appdomains, in a later post. Full-trust assemblies in the appdomain Finally, we need the strong names of the assemblies that, when loaded into the appdomain, will be run as full-trust, irregardless of the permissions specified on the appdomain. These assemblies will contain methods and classes decorated with SafeCritical and Critical attributes. I’ll be covering the details of creating full-trust APIs for partial-trust appdomains in a later post. This is how you get the strongnames of an assembly to be executed as full-trust in the sandbox: // get the Assembly object for the assembly Assembly assemblyWithApi = ... // get the StrongName from the assembly's collection of evidence StrongName apiStrongName = assemblyWithApi.Evidence.GetHostEvidence<StrongName>(); Creating the sandboxed appdomain So, putting these three together, you create the appdomain like so: AppDomain sandbox = AppDomain.CreateDomain( "Sandbox", null, appDomainSetup, restrictedPerms, apiStrongName); You can then load and execute assemblies in this appdomain like any other. For example, to load an assembly into the appdomain and get an instance of the Sandboxed.Entrypoint class, implementing IEntrypoint, you do this: IEntrypoint o = (IEntrypoint)sandbox.CreateInstanceFromAndUnwrap( "C:\temp\sandbox\SandboxedAssembly.dll", "Sandboxed.Entrypoint"); // call method the Execute method on this object within the sandbox o.Execute(); The second parameter to CreateDomain is for security evidence used in the appdomain. This was a feature of the .NET 2 security model, and has been (mostly) obsoleted in the .NET 4 model. Unless the evidence is needed elsewhere (eg. isolated storage), you can pass in null for this parameter. Conclusion That’s the basics of sandboxed appdomains. The most important object is the PermissionSet that defines the permissions available to assemblies running in the appdomain; it is this object that defines the appdomain as full or partial-trust. The appdomain also needs a default directory used for assembly lookups as the ApplicationBase parameter, and you can specify an optional list of the strongnames of assemblies that will be given full-trust permissions if they are loaded into the sandboxed appdomain. Next time, I’ll be looking closer at full-trust assemblies running in a sandboxed appdomain, and what you need to do to make an API available to partial-trust code.

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  • Should I choose Doctrine 2 or Propel 1.5/1.6, and why?

    - by Billy ONeal
    I'd like to hear from those who have used Doctrine 2 (or later) and Propel 1.5 (or later). Most comparisons between these two object relational mappers are based on old versions -- Doctrine 1 versus Propel 1.3/1.4, and both ORMs went through significant redesigns in their recent revisions. For example, most of the criticism of Propel seems to center around the "ModelName Peer" classes, which are deprecated in 1.5 in any case. Here's what I've accumulated so far (And I've tried to make this list as balanced as possible...): Propel Pros Extremely IDE friendly, because actual code is generated, instead of relying on PHP magic methods. This means IDE features like code completion are actually helpful. Fast (In terms of database usage -- no runtime introspection is done on the database) Clean migration between schema versions (at least in the 1.6 beta) Can generate PHP 5.3 models (i.e. namespaces) Easy to chain a lot of things into a single database query with things like useXxx methods. (See the "code completion" video above) Cons Requires an extra build step, namely building the model classes. Generated code needs rebuilt whenever Propel version is changed, a setting is changed, or the schema changes. This might be unintuitive to some and custom methods applied to the model are lost. (I think?) Some useful features (i.e. version behavior, schema migrations) are in beta status. Doctrine Pros More popular Doctrine Query Language can express potentially more complicated relationships between data than easily possible with Propel's ActiveRecord strategy. Easier to add reusable behaviors when compared with Propel. DocBlock based commenting for building the schema is embedded in the actual PHP instead of a separate XML file. Uses PHP 5.3 Namespaces everywhere Cons Requires learning an entirely new programming language (Doctrine Query Language) Implemented in terms of "magic methods" in several places, making IDE autocomplete worthless. Requires database introspection and thus is slightly slower than Propel by default; caching can remove this but the caching adds considerable complexity. Fewer behaviors are included in the core codebase. Several features Propel provides out of the box (such as Nested Set) are available only through extensions. Freakin' HUGE :) This I have gleaned though only through reading the documentation available for both tools -- I've not actually built anything yet. I'd like to hear from those who have used both tools though, to share their experience on pros/cons of each library, and what their recommendation is at this point :)

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  • ASP.NET MVC 2: Strongly Typed Html Helpers

    In this article, Scott examines the usage of Strongly Typed Html Helpers included with ASP.NET MVC 2. He begins with a short description of the existing HTML Helper method in ASP.NET MVC 1 and discusses the new methods, providing screenshots and a detailed listing of these new methods.

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  • C++ Programming: Implementation of the Licensing System For a Software Product

    This article is devoted to the development of the key licensing system for the applications. In the theoretical part of the article, we will examine the cryptography methods, which can be used while implementing the licensing system. Also we will discuss all pros and cons of these methods and select the possible ones for using in the application. In the practical part of the article, we will provide the implementation of the simplest licensing system, which guaranties the protection from cracking even if a hacker knows the source code of an algorithm.

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  • How do I make code bound to an ORM testable?

    - by RPK
    In Test Driven Development, how do I make code bound to an ORM testable? I am using a Micro-ORM (PetaPoco) and I have several methods that interact with the database like: AddCustomer UpdateRecord etc. I want to know how to write a test for these methods. I searched YouTube for videos on writing a test for DAL, but I didn't find any. I want to know which method or class is testable and how to write a test before writing the code itself.

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  • How to develop "Client script library" for ASP.net controls and how do these work?

    - by Niranjan Kala
    I have been working on .Net platform for 2 years and right now I am working on DevExpress controls for 6 months. All these control have client-side Events which are under some ClientScript nameSpace of particular control, Which specify ClientInstanceName, methods and properties accessible at client side. For example Button1 is ClientInstanceName and Button1.Text is a property, with methods like these: Button1.SetValue(); Button1.GetValue(); In ASP.Net Controls, buttons have the ClientClick event that fires before the Server Side Click event. I have inspected and goggled to extend client side functionality in asp.net controls. For example: create a ClientInstanceName property for controls or CheckedChanged event for CheckBox / RadioButton control. I have tried using these MSDN articles: Injecting Client-Side Script from an ASP.NET Server Control Working with Client-Side Script I got much information and ideas from these articles on how to implement/extend these. All are working in the client side. protected override void AddAttributesToRender(HtmlTextWriter writer) { base.AddAttributesToRender(writer); string script = @"return confirm(""%%POPUP_MESSAGE%%"");"; script = script.Replace("%%POPUP_MESSAGE%%", this.PopupMessage.Replace("\"", "\\\"")); writer.AddAttribute(HtmlTextWriterAttribute.Onclick, script); } Here It is just setting up attribute to the button. but all client side interaction no control from server. Here is that I want to know: How can I implement such functionality to create methods, properties etc. on client side. For example I am creating a PopControl as in the above code snippet same behavior as like Ajax ModalPopupExtender That have OK Button related properties. Ajax Controls can be directed to perform work from server side code e.g. Popup1.show(); How can I do this with such client enabled controls implemented controls as windows do? I am learning creation of Ajax Controls but I do not want to use ScriptManager or depend on another control. Just some extension to standard controls. I am expecting for ideas and implementation methods for such functionality.

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  • May I use full-texted feed for my News Reader app?

    - by Mahdi Ghiasi
    I'm creating a news reader app. (Users will choose sources, but not the exact feed addresses. for example, they can choose Gizmodo but they will not see the exact url of Gizmodo's feed) Some of sources are giving partial feeds, and user must go to their website to read the complete article. My question is, May I make a fulltext version of their feed (for example, using this service) and use it instead of their feed in my News reader categories? Am I legally/ethically allowed to do this? What about using some other service like Readability? (Readability gives HTML page instead of feed as input, but anyway, output will be clean article without any advertises or such) Please note that some of these partial feeds may have some advertises inside, but the fulltext feed generators usually remove that advertises.

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  • What type of code is suitable for unit testing?

    - by RPK
    In Test Driven Development, what type of code is testable? I am using a Micro-ORM (PetaPoco) and I have several methods that interact with the database like: AddCustomer UpdateRecord etc. I want to know how to write a test for these methods. I searched YouTube for videos on writing a test for DAL, but I didn't find any. I want to know which method or class is testable and how to write a test before writing the code itself.

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  • Game physics / 2D Collision detection AS3

    - by Jery
    I know there are some methods you can use like hittestPoint and so on, but I want to see where my movieclip colliedes with another another movieclip. Any other methods I can use? by any chance does somebody know some a good introduction to game physics? Im asking because I coded a small engine and pretty much the whole code is spagetti code thats why I would like to know how you can setup something like this properly

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  • PageMethods In ASP.NET AJAX

    Page Methods is a new mechanism in ASP.NET applications where the server code can be bound to ASP.NET pages. It is an easy way to communicate asynchronously with the server using ASP.NET AJAX technologies. It is an alternate to calling the page which is reliable and carries a low risk. It is basically used to expose the web methods to the client script.

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  • Are #regions an antipattern or code smell?

    - by Craig
    In C# code it allows the #region/#endregion keywords to made areas of code collapsible in the editor. Whenever I am doing this though I find it is to hide large chunks of code that could probably be refactored into other classes or methods. For example I have seen methods that contain 500 lines of code with 3 or 4 regions just to make it manageable. So is judicious use of regions a sign of trouble? It seems to be to me.

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  • Should main method be only consists of object creations and method calls?

    - by crucified soul
    A friend of mine told me that, the best practice is class containing main method should be named Main and only contains main method. Also main method should only parse inputs, create other objects and call other methods. The Main class and main method shouldn't do anything else. Basically what he is saying that class containing main method should be like: public class Main { public static void main(String[] args) { //parse inputs //create other objects //call methods } } Is it the best practice?

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