The website i am working now needs to have Facebook Login. I found 3 modules which could implement that feature.
Facebook Connect requires the Facebook PHP SDK and the configuration is quite user friendly and this is also the module which i used.
Facebook OAuth provides an API for authentication and does not need the Facebook PHP SDK. It fits for Drupal developesr who wants higher level of customization.
Drupal for Facebook seems to target Facebook application development. I didn’t tried it.
So let’s take a look on how to implement the Facbook Login feature with Facebook Connect.
1. Download and extract the Facebook PHP SDK @ sites/all/libraries.
2. Download and enable the module.
3. Enter the Facebook Application ID, the Application Secret as well as the Connect url @ admin/config/people/fbconnect.
4. Also set the urls @ admin/config/people/fbconnect/fb-app.
Now you could find the Facebook Login button on the login page and the Drupal login block.
Reference: Drupal module – Facebook Connect