Dealing with Oauth 2.0-facebook gem error 100: This authorization code has been used

Question

I have been working on setting up facebook authentication for my rails app and while testing, after logging-in with my facebook account, I keep getting this error:

Answer 1

This is due to Facebook changes that have been optional up until now but will roll out 12/5/12 for everyone. From the Developer Roadmap for the Dec '12 breaking changes:

New security restrictions for OAuth authorization codes We will only allow authorization codes to be exchanged for access tokens once and will require that they be exchanged for an access token within 10 minutes of their creation. This is in line with the OAuth 2.0 Spec which from the start has stated that "authorization codes MUST be short lived and single use". For more information, check out our Authentication documentation.

You'll need to update your app to account for this.

Cheers