Eld

gem "eld"

Eld.configure do |c|
  c.firebase_id = "FIREBASE_PROJECT_ID"
end

decoded_token = Eld.authenticate("FIREBASE_ACCESS_TOKEN")
# =>
{
  "iss" => "https://securetoken.google.com/fire-auth-67d5f",
  "aud" => "fire-auth-67d5f",
  "auth_time" => 1679606435,
  "user_id" => "Z02vuFq6RAU1NqVrWrdLAjyiqJ83",
  "sub" => "Z02vuFq6RAU1NqVrWrdLAjyiqJ83",
  "iat" => 1679606435,
  "exp" => 1679610035,
  "email" => "test@test.com",
  "email_verified" => false,
  "firebase" => {
    "identities" => {
      "email" => ["test@test.com"]
    },
    "sign_in_provider"=>"password"
  }
}

user = User.new(decoded_token)

Eld.configure do |c|
  # Use one or more Firebase projects
  c.firebase_id = "FIREBASE_PROJECT_ID"
  # c.firebase_id = ["FIREBASE_PROJECT_ID_1", "FIREBASE_PROJECT_ID_2"]

  # Use Redis to cache (recommended)
  # By default we use Eld::Cache::Memory
  # You can also create your own cache implementation.
  c.cache = Eld::Cache::Redis.new(
    client: Redis.new, # Your redis client
    cache_key: "eld/certificates" # Optional: This is the default key
  )

  # Use your own authenticator
  # See Eld::Authenticator for an example implementation.
  c.authenticator = CustomAuthenticator
end

Eld::Certificate.refresh

class CustomAuthenticator < Eld::Authenticator
  # The default behavior is to return the decoded token
  # You could add additional behavior like finding or instantiating
  # a user.
  def respond(decoded_token)
    User.find_by(uid: decoded_token['user_id'])
  end

  # The default authenticator swallows JWT errors
  # You might want to handle them on your own.
  def handle_error(error)
    ReportError.call(error)
    false
  end
end

# Set a new default authenticator
Eld.authenticator = CustomAuthenticator
Eld.authenticate(token)
# => User(uid: "1231231")

# Instantiate your own authenticator
authenticator = CustomAuthenticator.new(firebase_id: "FIREBASE_PROJECT_ID")
authenticator.authenticate(token)
# => User(uid: "1231231")

class ApplicationController < ActionController::Base
  before_action :authenticate_user!
  helper_method :current_user

  def authenticate_user!
    @current_user = nil

    token = request.headers["X-Access-Token"]
    decoded_token = Eld.authenticate(token)

    if payload
      # Find a User from DB?
      # Find or create a User?
      @current_user = User.find_by(uid: decoded_token['user_id'])

      # Wrap data in a User object?
      @current_user = User.new(decoded_token)
    end

    head :unauthorized unless @current_user
  end

  def current_user
    @current_user
  end
end