[OpenID] How to detect if a user is already logged

[Martin Atkins]

thomas Armstrong wrote:
> Hi.
> 
> I'm using "PHP OpenID Server by JanRain" as an OpenID server. It works
> ok and I can use web tools which require OpenID.
> 
> However, I'm creating another webtool and I want it to detect if a
> user is already logged in my server without typying their OpenID URL
> before.
> 
> Is there any protocolo already defined? I know that some web sites use
> a JavaScript redirection and a token system.
> 

I'm not sure I've understood your question fully, but here are some ideas:

  * Have the consumer site remember the user's OpenID Identifier in a 
cookie so that next time they arrive you can transparently log them in. 
Jyte uses this technique. They would still need to enter the identifier 
the first time, but subsequent visits would be automatic as long as the 
user stays logged in to the server.

  * If you're running both the consumer and the server, you could 
theoretically allow the two to collude to make sign-in automatic. 
Obviously this would only work as long as the client is using your 
OpenID server.