HOW TO: Rewrite URL / Implement URL Rewriting in ASP.NET

Solution

Reference articles:

• Tip/Trick: Url Rewriting with ASP.NET by Scott Guthrie - Examines four approaches: 1) Use Request.PathInfo Parameters Instead of QueryStrings; 2) Using an HttpModule to Perform URL Rewriting; 3) Using an HttpModule to Perform Extension-Less URL Rewriting with IIS7; 4) ISAPIRewrite to enable Extension-less URL Rewriting for IIS5 and IIS6; also discusses how to handle ASP.NET postbacks correctly with URL rewriting.

• URL Rewriting by Salman (CSharpFriends) - simple implementation of URL rewriting logic within the Application_BeginRequest() method of the Global.asax file.

• Search Engine Friendly URLs using ASP.NET (C#.NET) by Maziar Aflatoun (The UK Web Design Company) - similar to the above, but regular expression is used to match URLs.

• Rewrite.NET - A URL Rewriting Engine for .NET by Robert Chartier (15Seconds.com). Solution steps:
  • Create the HttpModule to process the web request and rewrite the URL
  • Add the handler in Web.config
  • Create a configuration section in Web.config to define URL mapping rules
  • Add extensibility by creating a rules engine interface
  • Write class or classes to implement rules engine interface
  • Add code to the HttpModule to dynamically load the desired rules from Web.config

• URL Rewriting in ASP.NET by Scott Mitchell (MSDN) - examines how to implement URL rewriting in a HTTP module; also explains how to handle postbacks.

• URL Rewriting with ASP.NET by Richard Birkby (CodeProject) - shows how legacy ASP sites can be upgraded to ASP.NET, while maintaining links from search engines. Solution steps:
  • Create the configuration section in Web.config for defining URL mapping rules
  • Write the configuration section handler class, incorporating the URL rewriting logic
  • Create a call to handler in Global.asax in Application_BeginRequest() method
  • Compile the code and install the rewriter assembly in the Global Assembly Cache (GAC)
  • Configure IIS to map non- .aspx files to the ASP.NET ISAPI extension

Related Resources

• Making Sense of ASP.NET Paths by Rick Strahl
• Fixing Microsoft's Bugs: URL Rewriting by Jesse Ezell
• Regular Expressions with .NET by Dan Appleman and Daniel Appleman
• UrlRewritingNet.UrlRewrite - an Open Source Component which allows you certainly to rewrite URLs with ASP.NET 2.0.
• Open Source URL Rewriter for .NET / IIS / ASP.NET