System.Web Namespace IHttpHandlerFactory Interface
Returns an instance of a class that implements the IHttpHandler interface.
[ VB ]
Function GetHandler ( _
ByVal context As HttpContext, _
ByVal requestType As String, _
ByVal url As String, _
ByVal pathTranslated As String _
) As IHttpHandler
[ C# ]
IHttpHandler GetHandler (
HttpContext context,
string requestType,
string url,
string pathTranslated
);
[ C++ ]
IHttpHandler* GetHandler (
HttpContext* context,
String* requestType,
String* url,
String* pathTranslated
);
[ JScript ]
function GetHandler (
context : HttpContext,
requestType : String,
url : String,
pathTranslated : String
) : IHttpHandler;
- context
- An instance of the HttpContext class that provides references to intrinsic server objects ( For example, Request, Response, Session, and Server ) used to service HTTP requests.
- requestType
- The HTTP data transfer method ( GET or POST ) that the client uses.
- url
- The RawUrl of the requested resource.
- pathTranslated
- The PhysicalApplicationPath to the requested resource.
A new IHttpHandler object that processes the request.
The following example creates custom handler objects in response to a client request for a page named either abc.aspx or xyz.aspx. The handler factory class named hwf creates the appropriate handler object depending on the page requested.
[ VB ]
' Name this Visual Basic file HandlerFactoryTest.vb and compile it with
' the command line: vbc /t:Library /r:System.Web.dll HandlerFactoryTest.vb.
' Copy HandlerFactoryTest.dll to your \bin directory.
Imports System
Imports System.Web
Namespace test
' Factory class that creates a handler object based on a request
' for either abc.aspx or xyz.aspx as specified in the Web.config file.
Public Class myFactory
Implements IHttpHandlerFactory
Public Overridable Function GetHandler ( context As HttpContext, _
requestType As String, url As String, pathTranslated As String ) _
As IHttpHandler _
Implements IHttpHandlerFactory.GetHandler
Dim fname As String = url.Substring ( url.LastIndexOf ( "/"c ) + 1 )
Dim cname As String = fname.Substring ( 0, fname.IndexOf ( "."c ) )
Dim className As String = "test." & cname
Dim h As Object = Nothing
Try ' to create the handler object.
' Create by calling class abc or class xyz.
h = Activator.CreateInstance ( Type.GetType ( className ) )
Catch e As Exception
Throw New HttpException ( "Factory couldn't create instance " & _
"of type " & className, e )
End Try
Return CType ( h, IHttpHandler )
End Function
' This is a must override method.
Public Overridable Sub ReleaseHandler ( handler As IHttpHandler ) _
Implements IHttpHandlerFactory.ReleaseHandler
End Sub
End Class
' Class definition for abc.aspx handler.
Public Class abc
Implements IHttpHandler
Public Overridable Sub ProcessRequest ( context As HttpContext ) _
Implements IHttpHandler.ProcessRequest
context.Response.Write ( "<html><body>" )
context.Response.Write ( "<p>ABC Handler</p>" & _
Microsoft.VisualBasic.ControlChars.CrLf )
context.Response.Write ( "</body></html>" )
End Sub
Public Overridable ReadOnly Property IsReusable ( ) As Boolean _
Implements IHttpHandler.IsReusable
Get
Return True
End Get
End Property
End Class
' Class definition for xyz.aspx handler.
Public Class xyz
Implements IHttpHandler
Public Overridable Sub ProcessRequest ( context As HttpContext ) _
Implements IHttpHandler.ProcessRequest
context.Response.Write ( "<html><body>" )
context.Response.Write ( "<p>XYZ Handler</p>" & _
Microsoft.VisualBasic.ControlChars.CrLf )
context.Response.Write ( "</body></html>" )
End Sub
Public Overridable ReadOnly Property IsReusable ( ) As Boolean _
Implements IHttpHandler.IsReusable
Get
Return True
End Get
End Property
End Class
End Namespace
[ C# ]
// Name this C# file HandlerFactoryTest.cs and compile it with the
// command line: csc /t:Library /r:System.Web.dll HandlerFactoryTest.cs.
// Copy HandlerFactoryTest.dll to your \bin directory.
namespace test
{
using System;
using System.Web;
// Factory class that creates a handler object based on a request
// for either abc.aspx or xyz.aspx as specified in the Web.config file.
public class myFactory : IHttpHandlerFactory
{
public virtual IHttpHandler GetHandler ( HttpContext context,
String requestType,
String url,
String pathTranslated )
{
String fname = url.Substring ( url.LastIndexOf ( '/' ) +1 );
String cname = fname.Substring ( 0, fname.IndexOf ( '.' ) );
String className = "test." + cname;
Object h = null;
// Try to create the handler object.
try
{
// Create the handler by calling class abc or class xyz.
h = Activator.CreateInstance ( Type.GetType ( className ) );
}
catch ( Exception e )
{
throw new HttpException ( "Factory couldn't create instance " +
"of type " + className, e );
}
return ( IHttpHandler ) h;
}
// This is a must override method.
public virtual void ReleaseHandler ( IHttpHandler handler )
{
}
}
// Class definition for abc.aspx handler.
public class abc : IHttpHandler
{
public virtual void ProcessRequest ( HttpContext context )
{
context.Response.Write ( "<html><body>" );
context.Response.Write ( "<p>ABC Handler</p>\n" );
context.Response.Write ( "</body></html>" );
}
public virtual bool IsReusable
{
get { return true; }
}
}
// Class definition for xyz.aspx handler.
public class xyz : IHttpHandler
{
public virtual void ProcessRequest ( HttpContext context )
{
context.Response.Write ( "<html><body>" );
context.Response.Write ( "<p>XYZ Handler</p>\n" );
context.Response.Write ( "</body></html>" );
}
public virtual bool IsReusable
{
get { return true; }
}
}
}
To use the above handler factory, add the following lines to the Web.config file.
<configuration>
<system.web>
<httpHandlers>
<add verb="*" path="abc.aspx" type="test.myFactory,HandlerFactoryTest" />
<add verb="*" path="xyz.aspx" type="test.myFactory,HandlerFactoryTest" />
</httpHandlers>
</system.web>
</configuration>
IHttpHandlerFactory Members
