Serve extensionless URL from ASP.NET without using ISAPI module or IIS 6 Wildcard mapping

29 Apr 2007 at 11:22

Omar AL Zabir

Blog Posts

If you want to serve extensionless URL from ASP.NET 2.0 like the following:

  • www.store.com/books
  • www.store.com/books/asp.net2.0
  • www.forum.com/post/how-to-serve-extensionless-url

You cannot, unless you use some third party ISAPI module or use IIS 6.0 Wildcard mapping feature. Third party ISAPI module needs to be installed on the server directly. If you don’t have a dedicated server or a VPS, you cannot do this. IIS 6.0 Wildcard mapping makes each and every request go through ASP.NET 2.0 ISAPI handler including Urls with .gif, .css, .js, .html etc. So, it suffers from scalability problem. Some independent research shows there’s 30% drop in performance in IIS 6.0 when you use wildcard mapping. So, this is not a good solution either.

Here’s an approach which works without using ISAPI module or wildcard mapping in IIS 6.0. When you request extensionless URL, you get HTTP 404. This means IIS receives the request but it serves the page configured for HTTP 404. It does not send the request to ASP.NET ISAPI. So, if you can forward all HTTP 404 to ASP.NET, you can serve such extensionless URL. In order to forward HTTP 404 to ASP.NET ISAPI, all you need to do is configure IIS to redirect to some .aspx extension on HTTP 404.

Benefits of this approach:

  • No thirdparty ISAPI module required
  • No Wildcard mapping thus no performance sacrifice

Here’s how to configure 404 redirection in IIS 6.0:

On IIS 6.0 change 404 default page to /404.aspx and the type to “URL”. On IIS 7.0, change 404 default page to /404.aspx and the type to “ExecuteURL”. Also, change the default error response to “Custom error pages”.

When you will request an URL like “www.shop.com/products/books” it will redirect to “www.shop.com/404.aspx?404;http://www.shop.com/products/books”. From Global.asax BeginRequest event, capture this URL and see whether it’s an extensionless URL request. If it is, do your URL rewriting stuff for such extensionless URL.

   1: protected void Application_BeginRequest(object sender, EventArgs e)

   2: {

   3:     string url = HttpContext.Current.Request.Url.AbsolutePath;

   4:

   5:     // HTTP 404 redirection for extensionless URL or some missing file

   6:     if (url.Contains("404.aspx"))

   7:     {

   8:         // On 404 redirection, query string contains the original URL in this format:

   9:         // 404;http://localhost:80/Http404Test/OmarALZabir

  10:

  11:         string[] urlInfo404 = Request.Url.Query.ToString().Split(';');

  12:         if (urlInfo404.Length > 1)

  13:         {

  14:             string originalUrl = urlInfo404[1];

  15:

  16:             string[] urlParts = originalUrl.Split('?');

  17:

  18:             string queryString = string.Empty;

  19:             string requestedFile = string.Empty;

  20:

  21:             if (urlParts.Length > 1)

  22:             {

  23:                 requestedFile = urlParts[0];

  24:                 queryString = urlParts[1];

  25:             }

  26:             else

  27:             {

  28:                 requestedFile = urlParts[0];

  29:             }

  30:

  31:             if( requestedFile.IndexOf('.') > 0 )

  32:             {

  33:                 // There's some extension, so this is not an extensionless URL.

  34:                 // Don't handle such URL because these are really missing files

  35:             }

  36:             else

  37:             {

  38:                 // Extensionless URL. Use your URL rewriting logic to handle such URL

  39:                 // I will just add .aspx extension to the extension less URL.

  40:                 HttpContext.Current.RewritePath(requestedFile + ".aspx?" + queryString);

  41:             }

  42:         }

  43:     }

  44: }
Digg This
Reddit This
Stumble Now!
Buzz This
Vote on DZone
Share on Facebook
Bookmark this on Delicious
Kick It on DotNetKicks.com
Shout it
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

No related posts.

If there were, in the heavens and the earth, other gods besides The God, there would have been confusion in both! But glory to The God, The Lord of the Throne: (High is He) above What they attribute to Him! (Quran 21:22)

←
→

15 Comments

Leave a Reply

 

Get Adobe Flash playerPlugin by wpburn.com wordpress themes