add Element for httpHandlers (ASP.NET Settings Schema)
Adds a handler to an application. A handler is an IHttpHandler or IHttpHandlerFactory interface that processes requests for specific URLs.
<configuration> Element
system.web Element (ASP.NET Settings Schema)
httpHandlers Element (ASP.NET Settings Schema)
add Element for httpHandlers (ASP.NET Settings Schema)
<add verb="verb list"
path="path/wildcard"
type="type,assemblyname"
validate="true|false" />
Attributes and Elements
The following sections describe attributes, child elements, and parent elements.
Attributes
Attribute |
Description |
|---|---|
path |
Required attribute. Specifies that the path attribute can contain either a single URL path or a simple wildcard string (for example, *.aspx). |
type |
Required attribute. Specifies a comma-separated class/assembly combination. ASP.NET searches for the assembly DLL first in the private \bin directory for the application, and then in the system assembly cache. |
verb |
Required attribute. Specifies that the verb list can be either a comma-separated list of HTTP verbs (for example, "GET, PUT, POST") or a start-script mapping (for example, the asterisk [*] wildcard character). |
validate |
Optional attribute. If false, ASP.NET will not try to load the class until the actual matching request comes. Potentially, this might delay the error but it does improve start-up time. |
Child Elements
None.
Parent Elements
Element |
Description |
|---|---|
configuration |
Specifies the root element in every configuration file that is used by the common language runtime and the .NET Framework applications. |
System.web |
Specifies the root element for the ASP.NET configuration section. |
httpHandlers |
Maps incoming requests to the appropriate IHttpHandler or IHttpHandlerFactory interface, according to the URL and the HTTP verb that is specified in the request. |
Remarks
The <httpHandlers> settings are inherited by subdirectives.
The <add> directives are processed in top-down, sequential order. If two or more <add> subdirectives specify the same verb/path combination, the final <add> overrides all others.
Microsoft Internet Information Services (IIS) has its own mode for mapping extensions to ISAPIs. For the settings for a given extension in this section to take effect, the extension must be mapped in IIS to ASP.NET ISAPI. For nonstandard extensions (something other than .aspx, .asmx, .asax, and so on), you must configure IIS.
Default Configuration
The following default add element is configured in the Machine.config file in the .NET Framework version 1.1.
<add verb="*" path="*.vjsproj" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.java" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.jsl" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="trace.axd" type="System.Web.Handlers.TraceHandler"/>
<add verb="*" path="*.aspx" type="System.Web.UI.PageHandlerFactory"/>
<add verb="*" path="*.ashx" type="System.Web.UI.SimpleHandlerFactory"/>
<add verb="*" path="*.asmx" type="System.Web.Services.Protocols.WebServiceHandlerFactory,
System.Web.Services, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
validate="false"/>
<add verb="*" path="*.rem" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory
System.Runtime.Remoting, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
validate="false"/>
<add verb="*" path="*.soap" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory,
System.Runtime.Remoting, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
validate="false"/>
<add verb="*" path="*.asax" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.ascx" type="System.Web.HttpForbiddenHandler"/>
<add verb="GET,HEAD" path="*.dll.config" type="System.Web.StaticFileHandler"/>
<add verb="GET,HEAD" path="*.exe.config" type="System.Web.StaticFileHandler"/>
<add verb="*" path="*.config" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.cs" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.csproj" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.vb" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.vbproj" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.webinfo" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.asp" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.licx" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.resx" type="System.Web.HttpForbiddenHandler"/>
<add verb="*" path="*.resources" type="System.Web.HttpForbiddenHandler"/>
<add verb="GET,HEAD" path="*" type="System.Web.StaticFileHandler"/>
<add verb="*" path="*" type="System.Web.HttpMethodNotAllowedHandler"/>
The following default add element is configured in the Machine.config file in the .NET Framework version 1.0.
<add verb="*" path="trace.axd" type="System.Web.Handlers.TraceHandler" />
<add verb="*" path="*.aspx" type="System.Web.UI.PageHandlerFactory" />
<add verb="*" path="*.ashx" type="System.Web.UI.SimpleHandlerFactory" />
<add verb="*" path="*.asmx" type="System.Web.Services.Protocols.WebServiceHandlerFactory,
System.Web.Services, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
validate="false"/>
<add verb="*" path="*.rem" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory,
System.Runtime.Remoting, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
validate="false"/>
<add verb="*" path="*.soap" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory,
System.Runtime.Remoting, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
validate="false"/>
<add verb="*" path="*.asax" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.ascx" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.config" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.cs" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.csproj" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.vb" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.vbproj" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.webinfo" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.asp" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.licx" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.resx" type="System.Web.HttpForbiddenHandler" />
<add verb="*" path="*.resources" type="System.Web.HttpForbiddenHandler" />
<add verb="GET,HEAD" path="*" type="System.Web.StaticFileHandler" />
<add verb="*" path="*" type="System.Web.HttpMethodNotAllowedHandler" />
The following default add element is configured in the root Web.config file in the .NET Framework version 2.0.
<add path="trace.axd" verb="*" type="System.Web.Handlers.TraceHandler" validate="True" />
<add path="WebResource.axd" verb="GET" type="System.Web.Handlers.AssemblyResourceLoader" validate="True" />
<add path="*.axd" verb="*" type="System.Web.HttpNotFoundHandler"
validate="True" />
<add path="*.aspx" verb="*" type="System.Web.UI.PageHandlerFactory" validate="True" />
<add path="*.ashx" verb="*" type="System.Web.UI.SimpleHandlerFactory" validate="True" />
<add path="*.asmx" verb="*" type="System.Web.Services.Protocols.WebServiceHandlerFactory,
System.Web.Services, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
validate="False" />
<add path="*.rem" verb="*" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory,
System.Runtime.Remoting, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
validate="False" />
<add path="*.soap" verb="*" type="System.Runtime.Remoting.Channels.Http.HttpRemotingHandlerFactory,
System.Runtime.Remoting, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
validate="False" />
<add path="*.asax" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.ascx" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.master" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.skin" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.browser" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.sitemap" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.dll.config" verb="GET,HEAD" type="System.Web.StaticFileHandler" validate="True" />
<add path="*.exe.config" verb="GET,HEAD" type="System.Web.StaticFileHandler" validate="True" />
<add path="*.config" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.cs" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.csproj" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.vb" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.vbproj" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.webinfo" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.licx" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.resx" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.resources" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.mdb" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.vjsproj" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.java" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.jsl" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.ldb" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.dsdgm" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.ssdgm" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.lsad" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.ssmap" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.cd" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.dsprototype" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.lsaprototype" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.sdm" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.sdmDocument" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.mdf" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*.ldf" verb="*" type="System.Web.HttpForbiddenHandler" validate="True" />
<add path="*" verb="GET,HEAD,POST" type="System.Web.DefaultHttpHandler" validate="True" />
<add path="*" verb="*" type="System.Web.HttpMethodNotAllowedHandler" validate="True" />
Example
The following code example demonstrates how to map all HTTP requests for files with the file name extension .New to the class MyHandler.New and for HTTP GET and HEAD requests for files with the file name extension .MyNewFileExtension to the class MyHandler.MNFEHandler. Both classes are in the assembly MyHandler that is in the file MyHandler.dll.
<configuration>
<system.web>
<httpHandlers>
<add verb="*"
path="*.New"
type="MyHandler.New,MyHandler"/>
<add verb="GET,HEAD"
path="*.MyNewFileExtension"
type="MyHandler.MNFEHandler,MyHandler.dll"/>
</httpHandlers>
</system.web>
</configuration>
Element Information
Configuration section handler |
|
Configuration member |
|
Configurable locations |
Machine.config Root-level Web.config Application-level Web.config Virtual or physical directory–level Web.config |
Requirements |
Microsoft Internet Information Services (IIS) version 5.0, 5.1, or 6.0 The .NET Framework version 1.0, 1.1, or 2.0 Microsoft Visual Studio 2003 or Visual Studio 2005 |
See Also
Tasks
How to: Lock ASP.NET Configuration Settings
Reference
httpHandlers Element (ASP.NET Settings Schema)
system.web Element (ASP.NET Settings Schema)
clear Element for httpHandlers (ASP.NET Settings Schema)
remove Element for httpHandlers (ASP.NET Settings Schema)
Concepts
ASP.NET Configuration Overview
ASP.NET Web Server Controls and Browser Capabilities
Securing ASP.NET Configuration
ASP.NET Configuration Scenarios
Other Resources
ASP.NET Configuration Settings