StackExchange OAuth and OpenID Authentication?

I have been having a goosey around the login functions of stackexchange, and I have noticed that depends on what you click, it adjusts a form with either OAuth information, or OpenID information in the form of the query which submits the form to a script inside of stackexchange, and I was wondering if anyone had the information for how the script would communicate with that particular service and use the returned information to login, as well as fetching additional information about that account from the se开发者_Python百科rvice.

If anyone has any scripts or snippets, PHP would be preferred.

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The Janrain OpenID Libraries are pretty good. They have a few quirks when it comes to extending them, but I think for your purposes they will be fine.

Facebook does NOT do OpenID. For Facebook you will need to use a different library (and that is something I have not done, so I cannot comment on it).