Opauth – “Login With Google, Twitter or Facebook” Made Easy
Authenticating users with well-known providers (like Google, Twitter or Facebook accounts) is widely used and an easy-to-use model for end-users.
However, when it comes to applying the feature, you need to deal with the requirements of each provider.
Opauth is an open source PHP library that removes the inconsistencies between providers and offers a standardized method for dealing with them.
Currently, 3 providers are almost plug 'n' play: Google, Twitter + Facebook and there are more to come. Also, there is support for dealing with any other Oauth provider.
Also, it integrates well with PHP frameworks including CakePHP, Yii and others to be added soon.