Step by Step Guide to Building an Auth0 API Integration in Ruby

Introduction

Hey there, fellow Ruby enthusiast! Ready to supercharge your app with some rock-solid authentication? Let's dive into integrating Auth0 into your Ruby project. Auth0 is a powerhouse when it comes to handling user authentication and authorization, and trust me, it'll make your life a whole lot easier.

Prerequisites

Before we jump in, make sure you've got:

• Ruby 2.7+ installed
• The auth0 and jwt gems
• An Auth0 account (if you don't have one, go grab it – it's free to start!)

Setting up the project

First things first, let's get our project off the ground:

mkdir auth0-ruby-api
cd auth0-ruby-api
bundle init

Now, crack open that Gemfile and add:

gem 'auth0'
gem 'jwt'

Run bundle install, and we're off to the races!

Configuring Auth0

Head over to your Auth0 dashboard and create a new API. Jot down your API identifier and signing secret – we'll need those in a bit.

Implementing Auth0 authentication

Let's create an Auth0 client:

require 'auth0'

auth0_client = Auth0Client.new(
  client_id: ENV['AUTH0_CLIENT_ID'],
  client_secret: ENV['AUTH0_CLIENT_SECRET'],
  domain: ENV['AUTH0_DOMAIN']
)

Pro tip: Use environment variables for those sensitive credentials. Your future self will thank you!

Building the API integration

Now, let's set up a simple Sinatra app to showcase our API:

require 'sinatra'
require 'jwt'

before do
  auth_header = request.env['HTTP_AUTHORIZATION']
  if auth_header
    token = auth_header.split(' ').last
    begin
      @decoded_token = JWT.decode(token, ENV['AUTH0_API_SECRET'], true, { algorithm: 'HS256' })
    rescue JWT::DecodeError
      halt 401, 'Invalid token'
    end
  else
    halt 401, 'No token provided'
  end
end

get '/api/protected' do
  'If you're seeing this, you're authenticated!'
end

Making authenticated requests

To hit your shiny new endpoint, you'll need to include the access token in your request header:

require 'httparty'

token = auth0_client.get_token
response = HTTParty.get('http://localhost:4567/api/protected',
  headers: { 'Authorization' => "Bearer #{token}" }
)
puts response.body

Error handling and best practices

Always validate tokens on the server-side, and never trust the client. Also, keep your secrets secret – use environment variables or a secure key management system.

Testing the integration

Don't forget to test! Here's a quick RSpec example to get you started:

require 'rspec'
require 'rack/test'

describe 'API' do
  include Rack::Test::Methods

  def app
    Sinatra::Application
  end

  it 'returns 401 without a token' do
    get '/api/protected'
    expect(last_response.status).to eq 401
  end

  it 'returns 200 with a valid token' do
    header 'Authorization', "Bearer #{valid_token}"
    get '/api/protected'
    expect(last_response.status).to eq 200
  end
end

Conclusion

And there you have it! You've just built a robust Auth0 API integration in Ruby. Remember, this is just scratching the surface – Auth0 has a ton of features to explore.

Keep coding, stay curious, and may your tokens always be valid! 🚀

For more in-depth info, check out the Auth0 Ruby SDK docs and the JWT gem documentation.