问题
I am getting the following error ("Error: HTTP status code: 400") now that I have updated to facebook SDK 3.1 as of yesterday, 10/9. But everything is completely functional as far as connecting with facebook, I just see this error message every time I start a facebook session on my app. I have seen a few people commenting on this, but I can't determine from them if this is going to be a real problem or not. Does anyone know definitively if this is going to cause a problem? And if so, how to fix it? Thanks!
回答1:
The original issue was resolved by Facebook just after the 3.1 SDK was released.
But some are still having issues, if you have this issue you should check the login flow, and look at facebooks examples, after that if you are still having issues this could be a hint to a solution.
I got the 400 error when I do not have authorization to get to my information. The strange thing is that I get an accessToken and even a valid login (this is because I structured my code, with the help according to Scrumptious example and did a valid login when the Session state is open).
The FBSessionState is only opened for like a second and then it changes to closed with an 400 Error.
With iOS6 native login you get the permission alert when you ask for it, and then the phone remember that choice for 24 hours. But if the user logs in to the facebook home-page and then deletes permission for the application the phone will not recognize that the user has deleted the permissions for 24 hours, since it remembers the that the phone has already asked it and approved it (in the 24-hour window), regardless if you re-install the app or not.
I found this out after some hours of debugging, since I allowed the application from the Settings in iOS, but I could not post, and since I deleted the permission from the facebook privacy, and the alert would not show again there was nothing I could do but to manually give me permissions via a debug tool or wait 24 hours so I could accept the facebook-permission alert again.
来源：https://stackoverflow.com/questions/12805743/facebook-sdk-3-1-error-http-status-code-400