How to auto-redirect URLs by patterns in ASP.NET / IIS 6?

Question

I thought it should be a simple straight-forward matter but after struggling with it for too much time I'm gonna have to seek for help.

What I need is to redirect all requests for my web application that match the following pattern - "^(http://[^/]+/blogs/[^/.]+)/?$" to the path of "$1/Default.aspx".

(Using English rather than Regex: http://myapp/blogs/randomdirthatdoesntexist -> http://myapp/blogs/randomdirthatdoesntexist/default.aspx)

The sub-directories in "blogs" do not physically exist, instead a 3rd party product deals with the requests to randomdir/Default.aspx", but when you go to "randomdir/" you get 404 not found, which is what I'm trying to fix.

I tried to use global.asax and also HttpHandler, but I couldn't get either of them to fire up on the requests to those 404 paths.

So, in short, what should I do to redirect paths of non-existing directories?

Thanks.

score 1 · Accepted Answer · answered Mar 09 '11 at 11:41

I accomplished something similar to this by setting the Error Page for 404s in IIS to a page you create. This page is able to access the page which is being requested, and perform some additional logic. So the 404 for randomdirthatdoesntexist/ still happens, but the 404 handler notices this and redirects to randomdirthatdoesntexist/default.aspx.

I dug out my old code and tweaked it a little to do what you need in an over-simplified fashion, but I don't have IIS6 anywhere to test:

protected void Page_Load(object sender, EventArgs e)
{
    String sQueryString = Request.RawUrl.Substring(Request.FilePath.Length);
    Regex rx = new Regex(@"^\?(?<errorcode>\d+);(?<args>.*)$", RegexOptions.ExplicitCapture | RegexOptions.Compiled);
    Match m = rx.Match(sQueryString);


    if (m.Success)
    {
        if (m.Groups["errorcode"].Value == "404")
        {
            String sArgs = m.Groups["args"].Value;
            Uri requestedUri = new Uri(sArgs);

            // You can now check the value of uri and perform redirection...
            if (requestedUri.ToString().EndsWith("/"))
            {
                Response.Redirect(requestedUri + "Default.aspx")
            }
        }
    }
    Response.StatusCode = 404;
}

Thanks, I ended up referring the 404 and 403 error pages in IIS to my HttpHandler, works like a charm — yellowblood, Mar 09 '11 at 13:15

score 0 · Answer 2 · edited May 23 '17 at 12:19

0

Use a Custom HttpModule, or Http Handler, which sits in early enough in the Http Request pipeline to direct your requests appropriately before any possible 404 response is determined.

See my own SO Q&A; Server.Transfer or Server.RewritePath for more details.

edited May 23 '17 at 12:19

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answered Mar 09 '11 at 11:40

Dave Anderson

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I didn't understand from this answer how am I supposed to put my HttpHandler earlier in the pipeline. – yellowblood Mar 09 '11 at 13:16
@yellowblood You add the HttpModule in the web.config and it can have custom code in Application_BeginRequest to alter the destination on the server of the HttpRequest using Server.Transfer. This is how URL rewriting often works. There is also Application_EndRequest which can modify the response just prior to it going back to the client. This article might give you a better idea; http://www.4guysfromrolla.com/articles/011404-1.aspx – Dave Anderson Mar 10 '11 at 01:57
Thanks for clearing that up, if I will ever face this issue again this seems like a better way of doing it. – yellowblood Mar 10 '11 at 11:06

How to auto-redirect URLs by patterns in ASP.NET / IIS 6?

2 Answers2