MSDN Magazine - January 2008 - (Page 66)

Figure 1 WebResource and ScriptResource References type=”text/javascript”> handler will be cached by the browser as long as the URI does not change. This means that if the assembly that serves the resource changes, its date/time stamp will change and the ScriptManager will generate a different URI (because there will be a different t parameter value) and the cached value will be replaced. The d parameter is encrypted so it makes no sense to the naked eye. However, the System.Web.UI.Page class has internal static methods—DecryptString and EncryptString—that allow the Page to build and un-build these strings. The decrypted version of the d parameter (wLnl3WuFAiWB3W8aelty5A2) in WebResource in Figure 1 is s|WebForms.js. The vertical bar is simply used to delimit different values in the string. The “s” indicates that the data is script, and “WebForms.js” is the name of the resource to retrieve. The WebForms.js resource is retrieved from System.Web.dll. The ScriptResource d parameters make for more interesting reading. The d parameters shown in Figure 1 are encrypted versions of this string ZSystem.Web.Extensions,1.0.61025.0,31bf3856ad364e35|MicrosoftAjax.js|en The decrypted version of this d parameter is ZAJAXEnabledWebApplicationI18N1|AJAXEnabledWebApplicationI18N1.DisplayFunctions.js|. It indicates that the ScriptResource HTTP handler should retrieve the AJAXEnabledWebApplicationI18N1.DisplayFunctions.js resource from the AJAXEnabledWebApplicationI18N1 assembly. Recall that we set the Build Action of this resource to embedded resource so it will be embedded in the assembly. It is also worth noting that the culture (at the end of the decrypted d parameter) is empty. When the browser’s language is set to fr, the culture value in the d parameter is set to fr. The final pieces of this jigsaw puzzle should fall into place if you consider the Z value at the beginning of the d parameter. Instead of Z for compressed, you might find a u, which indicates that the result should be returned uncompressed. So if you change this value to a u, rebuild the parameter (uAJAXEnabledWebApplicationI18N1|AJAXEnabledWebApplicationI18N1.DisplayFunctions.js|), encrypt it, and then call the ScriptResource HTTP handler directly, like this: http://localhost:49573/ScriptResource.axd?d=t9iZ-3-wfmF_ qcNwBHaQrktF2T3rVGzj376NN7kvehJFET0JsrpDTsYt9i KmZpSmrU1GjtTCo9PIQmuAmMNNkN2Yc_ipVH7JL-jt_hmL9_v8 HtplfhERvz-WsOUxZ-1k0&t=633137261664170000 Then you can see exactly what the handler is returning. Here’s the uncompressed, intelligible result: // JScript File function displayAlert() { window.alert(DisplayFunctionsResources.Greeting); return false; } DisplayFunctionsResources={ “Greeting”:”Hello World” }; and this string: ZSystem.Web.Extensions,1.0.61025.0,31bf3856ad364e35| MicrosoftAjaxWebForms.js|en The first character (Z) indicates that the result should be returned in GZip compressed format. The next paramThe result returned by eter is the fully qualified the HTTP handler will assembly name where the resource can be found be cached by the browser (the ASP.NET AJAX Sysas long as the URI does tem.Web.Extensions.dll in not change. this example). The parameter following that is the name of the resource to retrieve (in this instance, MicrosoftAjax.js), and the final parameter is the culture for which it should be retrieved (en for English in this case). If you view the HTML source for the sample application, you will see a third ScriptResource that is generated as a result of including the ScriptReference element in the ScriptManager. It looks like the following: <script src=”/ScriptResource.axd?d=SIfun5XG8AZLQEDQrC3E6MU4JIgMj1Y2u4fjk0_keEO3Avx4Kbf3v3a WEvpImtLlh3gxoqTDlXW5ZBtINnuNCTcGSSWUdsCxEJu9l3X fPtkrSmJXLzRqze5gVmu6Xzz0&t=633137261664170000” You can see that this is an amalgamation of the original DisplayFunctions.js file plus a JavaScript serialization of the DisplayFunctionsResources.resx. This amalgamation is serialized on request by the ScriptResource HTTP handler. Notice that the name of the JavaScript class is DisplayFunctionsResources. At first, you might think this is the name of the corresponding .resx file. However, this is a deliberate coincidence on my part. Recall the ScriptResource assembly reference from above: [assembly: System.Web.UI.ScriptResource (“AJAXEnabledWebApplicationI18N1.DisplayFunctions.js”, “AJAXEnabledWebApplicationI18N1.DisplayFunctionsResources”, “DisplayFunctionsResources”)] The final parameter (DisplayFunctionsResources) is the name of the JavaScript class that the ScriptResource HTTP handler generates. I chose this name because I think it is helpful to use the same name for the class and the file name, as this is the convention used by strongly typed resource classes. However, you can make these names different if you prefer. When you go ahead and switch the culture to fr, the ScriptResource HTTP handler returns an amalgamation using the DisplayFunctionResources.fr.resx resources (courtesy of the ResourceManager behavior that has existed since the release of the .NET Framework 1.0): 66 msdnmagazine aJaX world ready

Table of Contents Feed for the Digital Edition of MSDN Magazine - January 2008

MSDN Magazine - January 2008 Contents Toolbox CLR Inside Out Data Points Advanced Basics Cutting Edge IIS 7.0 - Enhance Your Apps with the Integrated ASP.NET Pipeline World Ready - Around the World with ASP.NET AJAX Applications WCF Syndication - HTTP Programming with WCF and the .NET Framework 3.5 Wicked Code Foundations Extreme ASP.NET {End Bracket}

MSDN Magazine - January 2008

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