Beyond web logs

Microsoft Office SharePoint Server 2007 has been redesigned completely when it comes to integrating with ASP.NET 2.0; it is now built on top of ASP.NET 2.0 and is far more reliant on the features provided by the ASP.NET 2.0 infrastructure.

In Microsoft Office SharePoint Server 2007, incoming requests are always handled first by the ASP.NET runtime. The SharePoint ISAPI filter has been removed, and instead the Microsoft  Office SharePoint Server 2007 infrastructure relies on ASP.NET 2.0 by defining HTTP modules and HTTP handlers responsible for handling SharePoint related requests.

In the web.config file of a SharePoint web application, you will notice that the <httpHandlers>
section contains an HTTP handler called Microsoft.SharePoint.ApplicationRuntime. SPHttpHandler. This handler ensures that the SPHttpHandler will eventually handle all requests for all file types (for instance, .aspx, .txt, .doc, or .docx files). You can find the web.config file by following these steps:

1. Open a command prompt and type the following command: inetmgr. This opens Internet Information Services (IIS) Manager.
2. Expand the [server name] (local computer) node.
3. Expand the Web Sites node.
4. Right-click the SharePoint web application and choose Properties. This opens the [web application] Properties window.
5. Click the Home Directory tab and copy the value of the Local path text field.
6. Open an instance of Windows Explorer and navigate to the path found in the previous step.
7. Open the web.config file found in this folder in any text editor.

When the ASP.NET engine is finished processing a request, it calls the SharePoint Virtual Path Provider (also known as the WSS File provider or SPVirtualPathProvider). ASP.NET 2.0 introduces the concept of virtual path providers, which are pluggable components that integrate with ASP.NET and can be used to parse .aspx pages. The SharePoint Virtual Path Provider is able to retrieve .aspx pages from a SQL Server database with full-text extensions and does not suffer from the limited functionality regarding page parsing found in SharePoint 2003. Microsoft Office SharePoint Server 2007 supports two types of pages: uncustomized and customized. Uncustomized pages are page templates that are located on the file system of the web server. Customized pages are modified page templates that are written to a SharePoint content database. One task the SharePoint Virtual Path Provider is responsible for when handling a page request is deciding whether the page is located on the file system or in a content database. The SafeMode parser optionally parses pages that are retrieved from the database.

After the SharePoint Virtual Path Provider has had the opportunity to handle (but not compile) a page, it returns the result to the ASP.NET engine that compiles the page, which then asks the virtual path provider to fetch the page layout class, which is also compiled. The ASP.NET engine adds SharePoint context data to the web metadata and then retrieves the master page associated to the SharePoint page. The master page is compiled, and a response is returned to the client. Following Figure shows an overview of the page-handling process in Microsoft Office SharePoint Server 2007.