OAuth 2.0 server in PHP, originally written for Open Dining. Supports IETF draft v9.

Source repo has sample servers implementations for PHP Data Objects and MongoDB. Easily adaptable to other storage engines.

PHP Data Objects supports a variety of databases, including MySQL, Microsoft SQL Server, SQLite, and Oracle, so you can try out the sample to see how it all works.

We're expanding the wiki to include more helpful documentation, but for now, your best bet is to view the oauth.php source -- it has lots of comments.

This project info taken from original page, oauth2-php on code.google.com