Android – validating Android’s authToken on third party server

accountmanagerandroidgoogle-apipicasa

I'm writing an Android application, which uses AccountManager to get the token. From an android app I'm able to interact with Google Picasa – it works fine.

What I would like to achieve is the following: send some text + authToken to my third party server, then check if the token is correct before saving the text. Now the question is: is it possible to determine if the authToken of a particular token is correct solely on the token itself (and maybe email address).

I've already programmed the server part, which accepts the token (send from android application), then issues a request to an URL address:

https://accounts.google.com/o/oauth2/tokeninfo?access_token=%token_here%

What I get back is the following JSON:

{
  "error" : "invalid_token"
}

But the link here http://oauthssodemo.appspot.com/step/4 states that if a token is correct I should receive a different JSON response. Can you tell me what I'm doing wrong: I believe that the way to check token's validity really isn't that simple, but I should rather implement the whole openid or something. Even if that is the case, how can I check whether the token send by android app is correct, so I can save the 'text' part of the message.

Thank you.

Best Solution

Stop using AccountManager and start using Google Play service’s GoogleAuthUtil class, then it gets easy. See http://android-developers.blogspot.ca/2013/01/verifying-back-end-calls-from-android.html

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