Those interested in the Apigility project from Zend might want to check out this new post from Ralph Schindler on how it handles authentication and authorization for all of the requests.
Apigility takes a lightweight, layered, yet extensible approach to solving both problems of authentication and authorization. The infrastructure is already in place and ready to be configured to use, or for more advanced use cases: to be extended. Many of these feature can be easily explored through the Apigility user interface.
He gets into authentication first, defining it briefly before getting into the Apigility-specific implementation. He talks about the three methods (HTTP basic, HTTP digest and OAuth2) and mentions where it falls in the execution as well as some screenshots of its setup. Following this he talks about the other half of the equation, authorization. He covers the "Authentication" header, the identity types and where you can find the configuration settings. He finishes off the post with an in-depth look at the different components, events and services/models that make up the authentication and authorization system and make it work.