Configuring OmniAuth with Devise

OmniWhat??

OmniAuth. It’s a gem for Ruby on Rails. And it’s great, for you and your users!

You can learn more about it here, but basically it allows your users to sign up/log in to your app using a third-party provider (e.g. Facebook, Google, Github, etc.) Now your lazy users don’t have to type as much or remember multiple passwords. Best of all, you can leave your users’ sensitive information in the hands of their advanced technology instead.

And What’s Devise again?

Another Rails gem. It sprinkles fairy dust all over your User model and makes your life 10x easier if you have lots of authentication needs. Otherwise, it’s unnecessary and can do more harm than good.

Got it. So how can I use both of these at the same time??

You’ve created a Rails application with an MVC framework and now you’re ready to configure OmniAuth with Devise.

Step 1.

Add the appropriate gems to your Gemfile and then run bundle install.

In this example I’d like my users to have the option of logging in with Facebook. You can have a different provider or have multiple different ones, all of which will need to be installed by a separate gem.

Step 2.

Set Up Devise. Enter the following commands in your terminal:

$ rails generate devise:install
$ rails generate devise User
$ rake db:migrate

Great! Now you have a User class and all of the associated sign in/sign up forms.

Step 3.

If you want to require your users to have an account and be logged in before accessing the views in your app, add the following code to your Application Controller:

Step 4.

Add columns to your User table in order to support OmniAuth. Run the following commands in your terminal:

$ rails g migration AddColumnsToUsers provider uid
$ rake db:migrate

Step 5.

Register your app at your provider’s website. This process might be different depending on your provider, but Google will have all your answers. Put this when prompted to enter a callback URL: http://localhost:3000/users/auth/[provider_name]/callback

Step 6.

Identify the Client ID and Client Secret from the provider and add them to /config/initializers/devise.rb:

Step 7.

Update your User model so that it looks like so:

The .from_omniauth makes the user information from the provider account accessible throughout the rest of your app.

Step 8.

Create a new controller to pass along the Omniauth callbacks. Create a new file called callbacks_controller.rb:

Step 9.

Specify the name of this new controller in your routes:

Now fire up your server and bask in the glory!