[Mediawiki-l] Problem implementing single-sign on for Wiki - values not visible in $_SESSION?

[Giles Thomas]

Hi all,

I am trying to implement a single sign-on system so that users of our 
site can register once and then edit our wiki and post to our phpBB 
forums without having to re-register and re-login.  I have the phpBB 
side of it working pretty well, but I'm having problems with my 
MediaWiki authentication plugin, and I was hoping someone might be able 
to point me in the right direction.

By way of background, my knowledge of PHP is pretty limited - Python, 
Java and C# are where my experience lies. 

In order to implement the plugin, I started with Jeremiah Orem's 
HttpAuth extension and switched the references to 
$_SERVER['PHP_AUTH_USER'] so that they looked at the "screenName" field 
on my own user objects, which I had stored in the PHP $_SESSION global .

My problem is that the user objects are not visible from the 
AutoAuthenticate hook that I've written.

My existing login page stores the ResolverUser object in the session 
with this code:

  function SetLoggedInUser($user)
  {
    session_start();
    $_SESSION['resolveruser'] = $user;
  }
*
*I register the AutoAuthenticate hook like this (in LocalSettings.php):

   require_once("$IP/extensions/ResolverAuthPlugin.php");
  $wgAuth = new ResolverAuthPlugin();
  $wgHooks['AutoAuthenticate'][] = array($wgAuth,'autoAuthenticate');

In the autoAuthenticate method of ResolverAuthPlugin, I call a function 
to get the user so that I can create a MediaWiki user if necessary:

  function GetLoggedInUser()
  {
    session_start();
    return $_SESSION['resolveruser'];
  }

But the user I get back is null.  If I go to any other page that calls 
the GetLoggedInUser() function, I get the correct value back, so I know 
it's there.  Perhaps there's some scoping issue with session values that 
I don't understand?  I am also suspicious of my multiple calls to 
session_start(), but they've been there for a while and haven't caused 
problems before...

Any hints or tips would be much appreciated; if this is off-topic for 
the list, my apologies and I'd be grateful to hear where the right place 
for questions like this is.


Regards,

Giles

-- 
Giles Thomas
MD & CTO, Resolver Systems Ltd.
giles.thomas at resolversystems.com
+44 (0) 20 7253 6372

17a Clerkenwell Road, London EC1M 5RD, UK
VAT No.: GB 893 5643 79 
Registered in England and Wales as company number 5467329.
Registered address: 843 Finchley Road, London NW11 8NA, UK