ASP. NET and IIS Server 7.0 Integration

In earlier versions of IIS servers, developers needed to write ISAPI extensions/filters to expand server functions. Besides being difficult to write, ISAPI is also very limited in terms of how to access the server and allow developers to customize.

For example, you cannot implement URL rewriting code in ISAPI extensions (Note: ASP. NET is implemented in the form of ISAPI extensions ). If you write long-running code into an ISAPI filter, the result is that you will occupy the I/O thread of the web server (this is why we do not allow the managed code to run in the Request Filter execution phase ).

A major architectural change we made to the core IIS server processing engine in IIS Server 7 is through a new modular request pipeline architecture to achieve extremely rich scalability.

You can now register an HTTP Extensibility Module with the web server to write code anywhere in the lifecycle of any HTTP request. These expansion modules can be written using native C ++ code or. NET managed code (you can use the existing ASP. NET System. Web. IHttpModule interface ).

All built-in IIS Server 7 functions (authentication, authorization, static file supply, directory list support, classic ASP, logging, etc ), currently, this public and modular pipeline API is used for implementation. This means that you can replace/extend these functions with your own implementations except for any of the S7 "built-in" functions of these IIS servers.

ASP. NET on IIS Server 7.0 has also changed from implementing ISAPI to directly accessing the module of IIS Server 7 pipeline.