Facebook signed_request无效

Question

So I've been fiddling about with creating a Facebook Page App and am running into an obstacle.

The API Documentation ( https://developers.facebook.com/docs/reference/login/signed-request/ ) indicates that it is a json encoded base64 encoded string, but I've found that more often then not it doesn't decode (PHP) properly.

Example String

[signed_request] => ccskn7MGtWvG9XXAU5F8nE61aFy-PP-2Jmvz35iwtOo.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImlzc3VlZF9hdCI6MTM4NjEyNTk5NCwicGFnZSI6eyJpZCI6IjM5ODYxMDQ0MDIxNDI2NiIsImxpa2VkIjpmYWxzZSwiYWRtaW4iOnRydWV9LCJ1c2VyIjp7ImNvdW50cnkiOiJ1cyIsImxvY2FsZSI6ImVuX1VTIiwiYWdlIjp7Im1pbiI6MjF9fX0

I did find this other question ( Invalid base64 in Facebook signed_request documentation example ), but after trying to add padding, still not gibberish results.

Any help is appreciated.

Answer 1

To parse the signed_request , first it must be split at the first dot . character, and then in the second part you have to replace the characters - and _ by + and / respectively – and after that base64-decode it.

As for your question, where this is documented – in the document that is linked right on top of the document that you mentioned, here: https://developers.facebook.com/docs/facebook-login/using-login-with-games/#parsingsr