[imp] custom_login.php / auto-login to imp w/ Horde 3.0 / IMP 4.0 beta

[Liam Hoekenga]

> You probably rather want a transparent authentication driver and hordeauth
> in IMP, just like you described below.
>
> How does authenticating agains the imap server work? With the kerberos user
> from REMOTE_USER and an empty/any password?

Yes.  With IMP 3.x and my modified version of redirect.php, I've been 
doing this:

     if (!isset($_POST['imapuser'])) {
         $_POST['imapuser'] = $_SERVER['REMOTE_USER'];
         $_POST['pass'] = $_SERVER['REMOTE_USER'];
         ...

> IMP with hordauth needs a password if I'm not wrong, so you have to 
> provide some.

I made a copy of horde/lib/Horde/Auth/http.php, calling it "cosign.php" 
and did..

     function transparent()
     {
         if (!empty($_SERVER['REMOTE_USER']) &&
             !empty($_SERVER['REMOTE_USER'])) {
             $this->setAuth($_SERVER['REMOTE_USER'],
                            array('password' => $_SERVER['REMOTE_USER'],
                                  'transparent' => 1));
             return true;
         }

         $this->_setAuthError(AUTH_REASON_MESSAGE,
                 _("HTTP Authentication not found."));
         return false;
     }

Basically... the Horde username is *always* going to be the same as 
$_SERVER['REMOTE_USER'] (set by our SSO), and the password is never needed 
for IMAP authentication, so it can be set (somehow) to anything we want.

Liam