redirect_uri_mismatch with OmniAuth Google oauth2 on Heroku

Question

I'm trying to setup a simple Rails application with OmniAuth using google auth.

When running the application on heroku, I get the following error when I try to access the oauth route, either directly or via redirect:

redirect_uri_mismatch

Request details:

access_type=offline
client_id=631910956855-pbglluk1ofb6vjmub9a0fucs8b0r5map.apps.googleusercontent.com
redirect_uri=http://stock-scraper-rails.herokuapp.com/auth/google_oauth2/callback
response_type=code
scope=email profile
state=94be59d4d241b70c83406ce59c36e7fc8d50279c

Works perfectly fine locally. I tried using a ngrok tunnel, and it also works.

Full url: https://accounts.google.com/o/oauth2/auth?access_type=offline&client_id=631910956855-pbglluk1ofb6vjmub9a0fucs8b0r5map.apps.googleusercontent.com&redirect_uri=https%3A%2F%2Fstock-scraper-rails.herokuapp.com%2Fauth%2Fgoogle_oauth2%2Fcallback&response_type=code&scope=email+profile&state=ac4cf27b4e2b534d854136ad25a102e2c1ff772d07dc84b8

My app is hosted on http://stock-scraper-rails.herokuapp.com You could go to /auth/google_oauth2 to see the error yourself.

I've search a bit but couldn't solve the problem. Here's what I already tried/did, but didn't solve the problem:

added domain to authorized domains
some answers to similar problems suggested waiting, because sometimes it takes google a while for google to update changes to domain. However, I have waited several hours already and the error persists
double/triple checked if my environment variables where correct on Heroku
checked Heroku log; there's no error there
setting OmniAuth.config.full_host manually

Callback route:

get '/auth/google_oauth2/callback', to: 'auth#oauth_callback'

I'm not using devise, by the way. Currently I simply want the controller do store some data in the session:

class AuthController < ApplicationController

  def oauth_callback
    authentication_google_data = request.env['omniauth.auth'].except(:extra)
    user_email = authentication_google_data['info']['email']
    # rest ommited
  end
end

OmniAuth configuration:

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :google_oauth2, ENV['GOOGLE_CLIENT_ID'], ENV['GOOGLE_CLIENT_SECRET']
end

Relevant gems versions:

rails (6.0.2.1)
omniauth (1.9.0)
omniauth-google-oauth2 (0.8.0)
omniauth-oauth2 (1.6.0)

Also tried to downgrade omniauth-oauth to 1.3.1, because read that there was a version causing a similar issue, with no success.

Any other ideas on what I could try would be very helpful :)

cesartalves cesartalves · Accepted Answer · 2020-03-04T13:21:32

I figured out what the problem was. On the google developer console for my app, on OAuth 2.0 Client IDs, I had created an ID with type "Other" instead of "Web application".

Creating a new one on https://console.cloud.google.com/apis/credentials?project=myproject with the type "Web application" and adding the callback url (both http and https) to Authorized redirect URIs solved the problem.

redirect_uri_mismatch with OmniAuth Google oauth2 on Heroku

1 Answers