Sharing google oauth verification code between android client and rails server

Question

I'm trying to setup a sign in via google+ within our mobile app.

So we have a Android client that fetchs a verification code for the oauth google api.

It then sends the verification_code back to rails and rails is responsible for getting the access token / refresh token pair and then talking to the api.

I'm having issue with validation the verification_code.

At first it would return

{
  "error" : "redirect_uri_mismatch"
}

So after reading a bit it seems that we should not specify a redirect_uri for android tokens but when I try to set redirect_uri to nil it fails with

{
  "error" : "invalid_request",
  "error_description" : "Missing parameter: redirect_uri"
}

I also tried by setting it to an empty string instead of nil and got the uri_mismatch again.

I tried to do a regular auth with a verification code obtained with the oauth playground and it works from there.

A bit of code

@authorization = CLIENT_SECRETS.to_authorization
@authorization.clear_credentials!
@authorization.grant_type = 'authorization_code'
@authorization.code = authorization_code
@authorization.redirect_uri = nil
@authorization.fetch_access_token!

Any help would be appreciated!

Answer 1

Ok so actually it was kinda of hidden but I found it.

So you need to set the redirect uri to the "out of band" uri set up within the credentials.

urn:ietf:wg:oauth:2.0:oob

The Client doesn't actually sets it to that value but I guess google defaults it to it.

The current signet gem does not allow redirect_uri to be set to that value so I added a PR to the main repo, In the mean time I'm using my fork and it works fine.

https://github.com/google/signet/pull/35

Answer 2

The Redirect URIs you send needs to match the one that you have set up in google apis console.

APIs & auth -> credentials