HTTP Handlers and HTTP Modules

HTTP Handler

- refered as endpoint

- runs in response to request made in application

- modules that handle the response

- common page handler = *.aspx, web service handler = *.asmx

- typical uses : RSS feeds, Image server

HTTP Modules

- called on every request made by application

- function handle the content

- examine incoming and outgoing request + take action based on request

- typical uses : security, statistic & logging, custom header & footer

- also uses to implement various application features, which includes forms authentication, caching, session state, and client script services.

Starting point :

IHttpHandler

- HTTPHandler (synchronous handler)

- Not return until HTTP request called process finished.

IHttpModule

- HTTPModule

IHttpAsyncHandler

- Asynchronous handlers

- runs process independently sending response to user.

- must implement the BeginProcessRequest & EndProcessRequest method

Source code puts in App_Code folder, when compiled put in Bin folder

Developed using IIS 6.0, can be used in IIS 7.0 (with a little/no change)

Creating HTTP modules

1) implements IHttpModule interface

2) write handler for Init method

* append something to response, uses EndRequest event

* perform custom authentication logic, uses AuthenticationRequest event

3) Write the code that you used.

4) Implement Dispose method for cleanup (optional)

5) Register module in Web.config

Creating HTTP handler
creating a class that implements the interface.