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: }
IIS will remove the If-Modified-Since header when redirecting to asp.net via the 404 page, other headers will remain intact.
I.e.
User sends If-Modified-Since: {date}, IIS strips it out, then redirects to 404 page. asp.net can then read any other header, like User Agent.
I am not sure why IIS would exhibit this behaviour.
Hai nice article Omer but i am getting an error like Cannot write virtual directory when using with IIS5.0 can u help on this
Very nice, was having a headache trying to come up with a solution for this. Thanks for the post.
One comment, is it really necessary to ToString() the Request.URL.Query? Seems it returns a string already?
-pete
Hi Omar, great solution. Is it possible the querystring wont be fired sometimes?
I absolutly love you ;o)!!! Good solution to a very annoying problem!!
I have a requirement to Inspect, the HttpMethod, From my client I am using a “POST”, but by the time it reaches the Module it has been changed to a “GET”. How can you ensure that the Post get passed properly?
Thanks,
OMG awesome, it took me exactly 5 min to solve a problem i had for a week. Url Rewritting is just a pain in the ass!!!
Thanks a lot Omar
This is a good approach. Sending 404s to aspnet seems much better than sending every request.
I am using this on local machine in IIS 5.1 it is working fine, but when i upload it on pre production with IIS6.0 t is not working.
please suggest
Sir, I’ve used same procedure. But again this is NOT Working. Can u just suggest me. Should i use Mapping. Using Shared server.
Sir,
I have implemented this solution in one of our site, It’s seems fine but for some user it showing 404.aspx page that we had set in IIS(while debugging i come to know that Begin_request event is not fire for some request), Could you please tell me the reason behind this Strange behaviour.
Regards,
Abdul Muheet
For what type of requests Begin_Request is not firing? WCF Service? HTML page?
Thanks for your reply Sir, Actually I had implemented it for aspx 2.0 website, For some machines it working fine but some users are complaining that they are getting the 404.aspx page. For Testing this I wrote a code that append current requested URL in txt file on Application_BeginRequest event in global.asax file, So when anyone request any page that URL will be appended in txt file, but for some users this event will not fire at all and url not appeneded on file, Is this Event fire at the start of the Application or for every request of each n every users this will be execute?, Please help me. Jazakallah..
Regards,
Abdul Muheet
Hi Sir,
I have figured it out it wasn’t Application_BeginRequest issue it was occured when someone type site URL without the www and i am replace http://www.sitename.com in my code. So now the issue has been resolved. Thanks
I could kiss you! Thank you! I *knew* this was possible, and have spent ages looking for it. Have asked on forums on how to do this, and got nowhere. (Favoured response there, if any, was MVC and URL ReWriter moduile – yuk.) The simplest answer is always the best.