What is the difference between 'classic' and 'integrated' pipeline mode in IIS7?
回答1
Classic mode (the only mode in IIS6 and below) is a mode where IIS only works with ISAPI extensions and ISAPI filters directly. In fact, in this mode, ASP.NET is just an ISAPI extension (aspnet_isapi.dll) and an ISAPI filter (aspnet_filter.dll). IIS just treats ASP.NET as an external plugin implemented in ISAPI and works with it like a black box (and only when it's needs to give out the request to ASP.NET). In this mode, ASP.NET is not much different from PHP or other technologies for IIS.
Integrated mode, on the other hand, is a new mode in IIS7 where IIS pipeline is tightly integrated (i.e. is just the same) as ASP.NET request pipeline. ASP.NET can see every request it wants to and manipulate things along the way. ASP.NET is no longer treated as an external plugin. It's completely blended and integrated in IIS. In this mode, ASP.NET HttpModules basically have nearly as much power as an ISAPI filter would have had and ASP.NET HttpHandlers can have nearly equivalent capability as an ISAPI extension could have. In this mode, ASP.NET is basically a part of IIS.
Internet Server Application Programming Interface (ISAPI), is an API developed to provide the application developers with a powerful way to extend the functionality of Internet Information Server (IIS).
回答2
Integrated application pool mode
When an application pool is in Integrated mode, you can take advantage of the integrated request-processing architecture of IIS and ASP.NET. When a worker process in an application pool receives a request, the request passes through an ordered list of events. Each event calls the necessary native and managed modules to process portions of the request and to generate the response.
There are several benefits to running application pools in Integrated mode. First the request-processing models of IIS and ASP.NET are integrated into a unified process model. This model eliminates steps that were previously duplicated in IIS and ASP.NET, such as authentication. Additionally, Integrated mode enables the availability of managed features to all content types.
Classic application pool mode
When an application pool is in Classic mode, IIS 7.0 handles requests as in IIS 6.0 worker process isolation mode. ASP.NET requests first go through native processing steps in IIS and are then routed to Aspnet_isapi.dll for processing of managed code in the managed runtime. Finally, the request is routed back through IIS to send the response.
This separation of the IIS and ASP.NET request-processing models results in duplication of some processing steps, such as authentication and authorization. Additionally, managed code features, such as forms authentication, are only available to ASP.NET applications or applications for which you have script mapped all requests to be handled by aspnet_isapi.dll.
Be sure to test your existing applications for compatibility in Integrated mode before upgrading a production environment to IIS 7.0 and assigning applications to application pools in Integrated mode. You should only add an application to an application pool in Classic mode if the application fails to work in Integrated mode. For example, your application might rely on an authentication token passed from IIS to the managed runtime, and, due to the new architecture in IIS 7.0, the process breaks your application.
Taken from: What is the difference between DefaultAppPool and Classic .NET AppPool in IIS7?
Original source: Introduction to IIS Architecture
ASP.NET 2.0 Breaking Changes on IIS 7.0
Introduction
ASP.NET 2.0 applications on IIS 7.0 and above are hosted using the ASP.NET Integrated mode by default. This new mode enables a myriad of exciting scenarios, including using valuable ASP.NET features such as Forms Authentication for your entire Web site, and developing new ASP.NET modules to do things such as URL rewriting, authorization, logging, and more at the IIS level. For more information about the ASP.NET Integration in IIS, see: ASP.NET Integration with IIS7 and Above.
While making ASP.NET applications more powerful in IIS 7.0 and above, we also worked diligently勤勉地 to ensure that existing ASP.NET applications continue to work when migrated to this new platform. This was a major challenge for us as we re-architected the entire core engine of ASP.NET, and in the end we were highly successful in meeting it. As a result, most ASP.NET applications should work without change.
This article lists the changes in behavior that you may encounter when deploying your ASP.NET applications on IIS 7.0 and above on Windows Vista SP1 and Windows Server 2008. Except where noted, these breaking changes occur only when using the default ASP.NET Integrated mode.