Ask a question. Quick access. Search related threads. Remove From My Forums. Answered by:. This can prevent thread blocking and can improve performance because only a limited number of threads can execute at the same time. If many users request synchronous HTTP handlers that rely on external processes, the operating system can run out of threads, because many threads are blocked and are waiting for an external process. When you create an asynchronous handler, you must implement the IHttpAsyncHandler interface.
You must also implement the BeginProcessRequest method in order to initiate an asynchronous call that processes individual HTTP requests. In addition, you must implement the EndProcessRequest method to run cleanup code when the process ends. A custom handler factory can give you finer control over how HTTP requests are processed by creating different handlers based on run-time conditions. To register a custom extension for a handler factory, follow the steps for registering a custom extension for a handler.
HTTP modules are called as part of the request pipeline and have access to life-cycle events throughout the request. HTTP modules therefore let you examine incoming requests and take action based on the request. They also let you examine the outgoing response and modify it. In IIS 6. NET request pipeline is separate from the Web server request pipeline. NET request pipeline and the Web server request pipeline can be integrated into a common request pipeline.
The unified pipeline has several benefits for ASP. NET developers. For example, it lets managed-code modules receive pipeline notifications for all requests, even if the requests are not for ASP. NET resources. However, if you want, you can run IIS 7. For more information, see ASP.
However, they are written in managed code and are fully integrated with the life cycle of an ASP. NET application. NET uses modules to implement various application features, which includes forms authentication, caching, session state, and client script services.
In each case, when those services are enabled, the module is called as part of a request and performs tasks that are outside the scope of any single page request. Modules can consume application events and can raise events that can be handled in the Global. For more information about application events, see ASP. An HTTP handler returns a response to a request that is identified by a file name extension or family of file name extensions.
In contrast, an HTTP module is invoked for all requests and responses. It subscribes to event notifications in the request pipeline and lets you run code in registered event handlers. The tasks that a module is used for are general to an application and to all requests for resources in the application. Modules must be registered to receive notifications from the request pipeline. When ASP. NET creates an instance of the HttpApplication class that represents your application, instances of any modules that have been registered are created.
When a module is created, its Init method is called and the module initializes itself. We can change the ContentType of the file and the Response content. Modify your Handler. Test handler. Here we test the new configuration and ASHX file on the local machine. Now click the green arrow to run your website on the development server.
You should see the image in your browser. This is the result of the handler. Add functionality. The example here so far is relatively useless.
All it does is allow us to pipe an image through an ASHX handler. You can add any functionality logging code or referrer logic to the handler in the C language.
Also, developers commonly need to use the QueryString collection on the Request. You can use the Request. The code is the same. What this does. The above code receives requests and then returns a different file based on the QueryString collection value.
It will return one of two images from the two query strings. The strings it returns are shown. Test query string. Does all this work? Yes, but it is always important to test. Open your browser. And on the path, add query strings like those shown above.
NET file that is not a typical web forms page. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
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