I'm trying to find information on securing a HTTP REST API in a Symfony project, but all I can find is information about using sfGuardPlugin. From what I can see, this plugin isn't very useful for web services. It tries to have user profile models (which aren't always that simple) and have "sign in" and "sign out" pages, which obviously are pointless for a stateless REST API. It does a lot more than I'll ever have need for and I what to keep it simple.
I want to know where to implement my own authorisation method (loosely based on Amazon S3's approach). I know how I want the authorisation method to actually work, I just don't know where I can put code in my Symfony app so that it runs before every request is processed, and lets approved requests continue but unsuccessful requests return a 403.
Any ideas? I can't imagine this is hard, I just don't know where to start looking.
I ended up finding what I was looking for by digging into the code for sfHttpAuthPlugin. What I was looking for was a "Filter". Some details and an example is described in the Askeet sample project.