OmniAuth is a Ruby on Rails library that provides standardized multi-provider authentication for web applications. It makes login easy for user by allowing them to use usernames and passwords from other websites to log into your app. OmniAuth works on a number of providers, such as Amazon, Github, and Facebook. A full list of provider strategies can be viewed here: https://github.com/omniauth/omniauth/wiki/List-of-Strategies
Each strategy is released as its own ruby gem and all of them can be found on RubyGems.
👍🏽OmniAuth works with Ruby web projects, so you will need to have either Sinatra or Rails installed in your project before beginning👍🏽
For the purposes of this guide, we will be looking specifically at the Facebook strategy for OmniAuth Facebook log in, as it is one of the more popular and also one of the more complex user authentication processes. We will also be focusing on Rails, but most of the information will be the same or translatable for Sinatra projects.
😺NOTE: In code examples, things that say YOUR_APP, YOUR-APP, or YOUR_FACEBOOK_APP_ID (and the like) will need to be replaced with whatever your app is called (the directory name, most likely) or your Facebook App ID. If things aren’t working, be sure to check those!😺
First you will need to add the following line to your
Any additional OmniAuth strategies will need to be added individually. Be sure that you install it after the Rails or Sinatra gem in your Gemfile. After you have entered the gem, run
bundle install the the terminal (in your app’s directory!)
The database now needs to be migrated as well as letting Rails know what information will need to be required, which we will accomplish by the following command in the terminal (again in your app’s directory):
rails g migration AddOmniauthToUsers provider:string uid:string
Then you will need to migrate the database, which can be done in Rails by this command in the terminal:
Get Facebook Information
Next you will need to register your app with Facebook and get log in credentials. Go to https://developers.facebook.com/ and click on “Add A New App” in the dropdown in the upper right corner of the page. Enter the name you wish to display on your app, a contact email, and select a category that best fits what your app does.
Click on Settings on the left side of the page and here you will see your App ID and App Secret key.
For my project, I used a localhost alternative, lvh.me. lvh.me is a domain that is set up to point to 127.0.0.1, which is localhost. This made the Facebook callbacks easier to work with and I highly recommend using it, but if you prefer trying localhost directly, that’s up to you!
Add your app’s domain name in App Domains. I’ll be using lvh.me, followed by the port number. Click on ‘Add Platform’ at the bottom of the page and select ‘Website’ followed by entering your Site URL. The Site URL and the App Domain will need to match.
In the root directory of your Rails project find (or if you don’t have it yet, create) a
.env file. On a new line add
YOUR_APP_SECRET with your App Secret key. There are no spaces and no quotation marks, brackets, or braces.
You will now use the
OmniAuth::Builder Rack middleware to build the list of strategies and what needs your app has for the use authentication in
'YOUR_FACEBOOK_APP_ID' with the App ID on your Facebook Developer dashboard and keep the single quote marks intact.
👍🏽Your App Secret key should remain private, so if you are using a public Git service, such as Github, remember to add your .env file to .gitignore. 👍🏽
One other file that will need to be added, if you don’t already have it, is a
Add the following to that file:
Integrating OmniAuth Facebook Into Application
OmniAuth was intentionally designed to be extremely agnostic as far as what providers you use and what information you can get from those providers. In the Facebook API we can get several different pieces of information from the user’s profile.
As an example, if you wanted to get a user’s home town you would put in the same
Any additional requests can be added below as a separate line in the same middleware.
In the same
config/initializers/omniauth.rb, we will add a logger at the top of the file:
OmniAuth.config.logger = Rails.logger
This will allow us to view the logs of OmniAuth communicating between the app and the Facebook Graph API.
One way to utilize OmniAuth is by linking it in a button to ask users to log in:
Which gives us a button that looks like this, with some styling:
Trying It Out
Try clicking the button or link to log into the site. The first time I tried this, I got this error:
This error was solved by entering the correct site on the Facebook Developers and making sure the Facebook Login Settings are set correctly:
👍🏽Remember to restart your Rails server if nothing else is working!👍🏽
By now you should be able to log into your site using the Facebook OmniAuth gem. OmniAuth is an easy way to use the Facebook API in Ruby web applications.
More information about OmniAuth and the Facebook API can be viewed at:
The Github page for OmniAuth-Facebook: https://github.com/mkdynamic/omniauth-facebook
Using the Facebook API: https://developers.facebook.com/