ASP.NET in a Nutshell

Name

IHttpHandler

Synopsis

This interface is required to process HTTP requests. It’s implemented by the System.Web.UI.Page and HttpApplication classes, but you can use IHttpHandler to create a custom HttpHandler for a lower-level programming model. You can still access the HttpContext object (and, through its properties, built in objects like HttpRequest and HttpResponse), but you cannot use the higher-level Page abstraction. Common uses of handlers include filters and CGI-like applications, especially those returning binary data.

When using the IHttpHandler interface, you must implement the ProcessRequest() method and IsReusable property. The ProcessRequest() method receives an HttpContext object, which gives you access to ASP.NET’s built-in objects. Use the IsReusable property to declare whether a single instance of your handler can serve multiple requests.

You will also need to modify <httphandlers> section of the web.config file to make your custom handler a target for HTTP requests. You can map requests based on the requested page, file type, or HTTP method (GET, PUT, or POST). If you want to create a handler that can process all requests, you should create a custom HttpModule using the IHttpModule interface.

Public Interface IHttpHandler
                  ' Public Instance Properties
   Public ReadOnly Property IsReusable As Boolean  
' Public Instance Methods
   Public Sub ProcessRequest(ByVal context As HttpContext) 
End Interface