what is the exact purpose of http handlers and interfaces?

httphandler: does the mapping of incoming URLs. This is the last part of the http request. 
 
Ex: http://servername/project/trace.axd 
( The trace.axd file is being requested by the user. The URL checks for httphandler section name in the web.config,  
 
 
 
 
 
 
 
Then returns the particular file(trace.axd) 
 
Note: trace.axd of a particular file is stored in the root directory of that application.

Hi Binda,

I am sorry to say that you have provided us a wrong answer to the question :( .

Guys please refer to the following link to get a better insight of HTTP Handlers and HTTP Modules....

http://www.15seconds.com/issue/020417.htm

Hope this information is useful....Happy Programming !!!

Regards,

Raja

HTTP handlers is a process that runs in a response to request made to an asp.net web application

The most common handler is an ASP.NET page handler that processes .aspx files

other handlers are

Web service handler (*.asmx) ->HTTP handler for Web service pages created using ASP.NET.

like this...

ASP.NET maps HTTP requests to HttpHandlers. Each HttpHandler enables processing of individual HTTP URLs or groups of URL extensions within an application. HttpHandlers have the same functionality as ISAPI extensions with a much simpler programming model

Ex
1.Default HttpHandler for all ASP.NET pages ->ASP.NET Page Handler (*.aspx)
2.Default HttpHandler for all ASP.NET service pages->ASP.NET Service Handler (*.asmx)

An HttpHandler can be either synchronous or asynchronous. A synchronous handler does not return until it finishes processing the HTTP request for which it is called. An asynchronous handler usually launches a process that can be lengthy, and returns before that process finishes
After writing and compiling the code to implement an HttpHandler, you must register the handler using your application's Web.config file.

Handlers are used to process individual endpoint requests. Handlers enable the ASP.NET framework to process individual HTTP URLs or groups of URL extensions within an application. Unlike modules, only one handler is used to process a request. All handlers implement the IHttpHandler interface, which is located in the System.Web namespace. Handlers are somewhat analogous to Internet Server Application Programming Interface (ISAPI) extensions.