An HTTP handler is a process that runs on server to response to a
particular type of request. HTTP handlers can be referred to as endpoint
also. A typical example of HTTP handlers is when ASP.net page handler
which is used by asp.net engine to process the request that come for
.aspx files.
Built In HTTP Handlers in ASP.net
| Handler |
Description |
| ASP.net Page Handler (*.aspx) |
A default page handler for all ASP.net
pages. |
| Web Service handler(*.mspx) |
The default HTTP handler for Web service
pages created as .asmx files in ASP.NET. |
|
Generic Web handler (*.ashx)
|
The default HTTP handler for all Web
handlers that do not have a UI and that include the @ WebHandler
directive. |
|
Trace handler (trace.axd)
|
A handler that displays current page trace
information. For details, see How to: View ASP.NET Trace Information
with the Trace Viewer. |
How to Create A Custom HTTP Handler
To create a custom HTTP Handler you need to implement either
IHttpHandler or IHttpAsyncHandler for synchronous and asynchronous
handlers. Both these interfaces expose two methods called IsReusable and
ProcessRequest. ProcessRequest method is the place where you write code
for handling request of your custom handler. The IsReusable property
specifies whether the IHttpHandlerFactory object (the object that
actually calls the appropriate handler) can put the handler in a pool
and reuse it to increase performance. If the handler cannot be pooled,
the factory must create a new instance of the handler every time that
the handler is needed.
Public Class CustomHand
Implements IHttpHandler
Public ReadOnly Property IsReusable() As Boolean Implements System.Web.IHttpHandler.IsReusable
Get
End Get
End Property
Public Sub ProcessRequest(ByVal context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest
End Sub
End Class
Mapping File Extension in IIS
By Default IIS is going to respond to file extension that is for
custom handler. If you created a new file extension for HTTP Handler
then you have to explicitly register the file extension in IIS and have
to add a mapping entry in web.config file for your custom handler.