HTTP Handler and HTTP Module

1. What is Http Handlers?

1. ASP.NET HttpHandler is a class that implements the System.Web.IHttpHandler interface.
2. HTTPHandlers are used by ASP.NET to handle the specific requests based on extensions.
3. There is one Handler for a specific request but there could be N number of modules for that.
4. The class should have a method ProcessRequest and a property called IsReusable.
5. Web.config settings

  <configuration>

     <system.web>

        <httpHandlers>

           <add verb="*" path="*.sync" type="MyHandler.SyncHandler, MyHandler" />

        </httpHandlers>

     </system.web>

  </configuration>

       

 In the verb="*" attribute, we instruct the handler to process a request that uses any verb (for example, POST, HEAD, GET, and so on).

 If you want this handler to process only the POST request, change this to verb="POST".

 In the path="*.sync" attribute, we instruct the handler to process any incoming requests for files with the .sync extension.

 In the type="MyHandler.SyncHandler, MyHandler" attribute, we instruct the handler that processes the request to implement in the MyHandler.SyncHandler

 namespace, and this class resides in the MyHandler assembly.

       6.ASP.NET offers a few default HTTP handlers:

•   Page Handler (.aspx): handles Web pages
•   User Control Handler (.ascx): handles Web user control pages
•   Web Service Handler (.asmx): handles Web service pages
•   Trace Handler (trace.axd): handles trace functionality

2.What is Http Modules?  

1. ASP.NET Http Modules is a class that implements the System.Web.IHTTPModule interface.
2. Http Modules are used by ASP.NET to handle the requests based on events.
3. There are N number of modules one for a specific Handler for that.
4. The class should have two methods Init and Dispose.
5. Web.config settings

  <system.web>

    <httpModules>

      <add name="MyModule"type="MyModule.SyncModule, MyModule" />

    </httpModules>

  </system.web>

     6.  The built-in modules in ASP.NET are:

•   Output Cache Module
•   Windows Authentication Module
•   Forms Authentication Module
•   Passport Authentication Module
•   URL Authorization Module
•   File Authorization Module

3. Difference between Http Handlers and Http Modules

• HTTP handlers are the end point objects in ASP.NET pipeline.
• HTTP Modules are objects which participate the pipeline but they work before and after the HTTP Handler.
• HTTP Handlers are extensions based.
• HTTP Modules are events based.
• There is one Handlers for a specific request.
• There are many handlers for a specific request.
• Implements the System.Web.IHttpHandler interface.
• Implements the System.Web.IHTTPModule interface.

4. Processing Sequence of Http Handlers and Http Modules

In the asp.net request pipe line, http Module comes first.