basecamp/google_sign_in

Name: google_sign_in

Owner: Basecamp

Description: Sign in (or up) with Google for Rails applications

Created: 2017-05-30 13:46:32.0

Updated: 2018-03-29 03:16:22.0

Pushed: 2018-03-02 14:48:12.0

Homepage: null

Size: 17

Language: Ruby

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README

Google Sign-In for Rails

Google Sign-In provides an easy and secure way to let users signin into and up for your service, without adding yet-another per-app email/password combination. Integrating it into your Rails app should be drop-in easy. This gem makes it so.

The only configuration needed is setting the Google client id for your application. Google has a tutorial on how to setup a client id.

Once you have your client id, create a config/initializers/google_sign_in_client_id.rb file with this: GoogleSignIn::Identity.client_id = <THAT CLIENT ID YOU GOT FROM GOOGLE>

Now you can use the sign-in integration on your signup or signin screen.

Example

Here's the most basic example:

p/views/layouts/application.html.erb
l>
d>
 Required for google_sign_in to add the Google JS assets and meta tags! %>
yield :head %>
ad>
y>
yield %>
dy>
ml>

p/views/sessions/new.html.erb
google_sign_in(url: session_path) do %>
You can replace this with whatever design you please for the button.
You should follow Google's brand guidelines for Google Sign-In, though:
https://developers.google.com/identity/branding-guidelines
= button_tag("Signin with Google") %>
nd %>

The url option is the URL that the hidden form will be submitted against along with the Google ID Token that's set after the user has picked the account and authenticated in the pop-up window Google provides.

You can then use that in a sessions controller like so:

s SessionsController < ApplicationController
f new
d

f create
if user = authenticate_via_google
  cookies.signed[:user_id] = user.id
  redirect_to user
else
  redirect_to new_session_url, alert: "authentication_failed"
end
d

ivate
def authenticate_via_google
  if params[:google_id_token].present?
    User.find_by google_id: GoogleSignIn::Identity.new(params[:google_id_token]).user_id
  end
end

(This example assumes that a user has already signed up for your service using Google Sign-In and that you're storing the Google user id in the User#google_id attribute).

That's it! You can checkout the GoogleSignIn::Identity class for the thin wrapping it provides around the decoding of the Google ID Token using the google-id-token library. Interrogating this identity object for profile details is particularly helpful when you use Google for signup, as you can get the name, email address, avatar url, and locale through it.

Compatibility with Turbolinks

Google's JavaScript doesn't play nice with Turbolinks. We've routed around the damage by adding a Turbolinks meta tag on whatever page google_sign_in is called to always do a full reload for that page. Note that this auto-compatibility feature requires Turbolinks 5.1+.

License

Google Sign-In for Rails is released under the MIT License.