ASP.NET's built-in HTTP Handler and Module generates one HTTP request per file and loads these files sequentially when a browser loads a web page.
If a web page contains many files (such as scripts, styles, binary data, etc.), its loading can take a significant amount of time.
The DevExpress ASP.NET subscription includes the ASPxHttpHandlerModule (the DevExpress HTTP Handler and Module) that is implemented instead of the standard HTTP Resource handler and increases a web page’s loading speed.
The ASPxHttpHandlerModule can function as both a handler and a module.
The ASPxHttpHandlerModule has access to ASP.NET application lifecycle events (it is subscribed to an application's PreSendRequestHeaders and AuthenticateRequest events) and can assess incoming requests and modify outbound responses. For example, it can handle server-side exceptions and standard response redirection, as well as check authentication expiration.
The primary ASPxHttpHandlerModule features are listed below.
Process callback requests from DevExpress web controls, compress callbacks and resolve exceptional situations that may arise during callback processing. See Overview - Callback Exception Handling for more information.
Obtain binary data (DevExpress Gauges, Charts, and ASPxBinaryImage controls) from the server without loading the page's hierarchy.
When you create a custom assembly that contains DevExpress resources, set the WebResourceAssembly(assemblyID) attribute - to specify that the assembly can export resources via the ASPxHttpHandlerModule. Set the assemblyID attribute to a value greater than 100 to avoid conflicts (key values from 0 to 100 are reserved for DevExpress controls).