RestFB: Facebook HTTP 400 error not specific enough

I'm using RestFB in order to connect our online photo sharing app to Facebook. But sometimes, Facebook is simply returning HTTP 400 errors to s开发者_运维知识库ome queries. After investigation, the reasons can vary (number of posts on the wall limit reached, access token invalidated by user or even response time to long), but fact is: I don't know how to catch which error happened. That's a real issue, because obviously, the processing should not be the same: if the access token is invalidated, I would like to prompt the user in order to let him accept the application again, but if the FB plateform is simply unresponsive, I could for example try again after some time. Any clue?

I'm Mark Allen (RestFB maintainer). Version 1.6 should address this bug.