How to make ASP.NET authentication persist the Url Fragment when redirecting to the login page?

Question

After I inserted the configuration below in my Web.Config

<authentication mode="Forms">
  <forms name="appNameAuth"
   path="/" loginUrl="login.aspx" protection="All" timeout="30">
    <credentials passwordFormat="Clear">
      <user name="user" password="password" />
    </credentials>
  </forms>
</authentication>
<authorization>
  <deny users="?" />
</authorization>

All requests to

Menu.aspx#fragment

are redirected to

login.aspx?ReturnUrl=/Menu.aspx

and I expected it to be redirected to

login.aspx?ReturnUrl=/Menu.aspx#fragment

How to achieve the desired behavior?

Answer 1

That #fragment anchor tag is a client side (browser) component of the URL. It doesn't get sent to the WebServer as far as I know so the server-side has no clue about it as part the redirect.

EDIT

Can you check your IIS logs and confirm that because I'm 99% sure that that's not the case.

From a quick test on my local machine.

1. Attempt to browse to

   http://localhost/formstest/private.aspx#test

2. Get Redirected

   http://localhost/formstest/login.aspx?redirect=http%3a%2f%2flocahost%2fformstest%2fprivate.aspx#test

   (Notice the # is not escaped as part of the redirect url.

3. Check IIS for first hit.

   2010-04-12 13:36:45 W3SVCxxx 127.0.0.1 GET /formstest/private.aspx 80 - DETAILS SNIPPED - 302 0 0

   (Notice the 302 Redirect and the absense of the #test token on the URL

4. Check IIS for the redirect hit.

   2010-04-12 13:36:46 W3SVCxxx 127.0.0.1 GET /formstest/login.aspx redirect=http%3a%2f%2flocahost%2fformstest%2fprivate.aspx 80 - DETAILS SNIPPED - 200 0 0

   (There's your 200 OK HTTP Response and still no #test

Like I said, the server doesn't know anything about the #anchor. It's only on the client side regardless of whether you put it in before or after the request is made, or whether you update it with JQuery... it doesn't go to the server.

Answer 2

The only solution I have found so far is to use a Rewrite rule to encode the # character to %23.

Thanks Claudio!