Http Handler And Http Module

Http Module and Http Handler

 

. Relation

 

.Page Event Pipe

 

For Http Module:

 

1. ·        for each request, all http modules will be go through .
2. ·        if have multiple modules ,execute order ?  for example :

 

Module A, which subscribes toEndRequest

Module B, which subscribes toBeginRequest and EndRequest

Module C, which subscribes toAuthenticateRequest

The order of execution will be:

 

Module B, BeginRequest

Module C, AuthenticateRequest

Module A, EndRequest

Module B, EndRequest

 

For Http Handler

 

for each request , only ONE handler will be mapped to do some logic, depending on the configuration in web.config.

 

.configuration :

 

for http module :

 

<system.webServer><modules>      <addname="urlRewrittingModule"type="WebCode.asp.net.HttpModule.UrlRewriterModule"/></modules></system.webServer>

 

for http handler:

 

 

<system.webServer><handlers>      <addverb="*" name="urlRewritingHandler" path="*.aspx"type="WebCode.asp.net.HttpHandler.UrlRewriterHandler"/></handlers></system.webServer>

 

when use

 

Http Handler

Whenever want to handle some request but no need the UI page

 

Http Module

Authentication ,Application  log , Auditing , URLRewriting

 

code example :

 

http module(using http module to rewrite url) :

 

public class UrlRewriterModule : IHttpModule    {        public voidDispose()        {            //clean-upcode here.        }         public voidInit(HttpApplication context)        {           context.AuthenticateRequest += ContextOnAuthenticateRequest;           context.BeginRequest += ContextOnBeginRequest;           context.AuthorizeRequest += context_AuthorizeRequest;           context.PreRequestHandlerExecute += ContextOnPreRequestHandlerExecute;           context.PostRequestHandlerExecute += ContextOnPostRequestHandlerExecute;           context.EndRequest += ContextOnEndRequest;        }         #region BEFOREhandler        private void ContextOnPreRequestHandlerExecute(objectsender, EventArgs eventArgs)        {        }        private voidcontext_AuthorizeRequest(object sender, EventArgs e)        {        }        private voidContextOnBeginRequest(object sender, EventArgs eventArgs)        {            //test URLrewritten            varcontext = ((HttpApplication)sender).Context;            if(context.Request.RawUrl.Contains("ExploreRedirect"))            {               context.RewritePath("ExploreRedirect.aspx","","SN="+ Guid.NewGuid());            }        }        private voidContextOnAuthenticateRequest(object sender, EventArgs eventArgs)        {        }        #endregion        #region AFTERhandler        private voidContextOnEndRequest(object sender, EventArgs eventArgs)        {        }        private voidContextOnPostRequestHandlerExecute(object sender, EventArgs eventArgs)        {        }        #endregion    } 

 

http handler:

 

  

public classUrlRewriterHandler : IHttpAsyncHandler    {        public voidProcessRequest(HttpContext context)        {           //dosomething                 }         privateAction<HttpContext> _process;        public boolIsReusable { get; private set; }         publicIAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, objectextraData)        {            _process =ProcessRequest;            return_process.BeginInvoke(context, cb, extraData);        }         public voidEndProcessRequest(IAsyncResult result)        {           _process.EndInvoke(result);        }    }