How to decode base64 url in python?

Question

For Facebook fbml Apps Facebook is sending in a signed_request parameter explained here:

http://developers.facebook.com/docs/authentication/canvas

They have

Answer 1

Alternative to @dae.eklen's solution, you can append === to it:

s = 'iEPX-SQWIR3p67lj_0zigSWTKHg'
base64.urlsafe_b64decode(s + '===')

This works because Python only complains about missing padding, but not extra padding.