I am trying to run the quick start code of Real Time API of Google Drive. I believe I did everything right. But I am getting
Error: origin_mismatch
Request
You haven't given much detail about your application architecture, so i can only suggest a general answer. OAuth restricts which URLs can be referred to it. The list of permitted URLs is configured in the API console at https://code.google.com/apis/console. The URL is very fussy, so make sure you enter it exactly as it appears in the address bar.
As at Oct 2013, you can't use localhost. You have 2 choices.
However, I believe that it is now possible to configure localhost in the Google api console.