Rack Middleware

middleware.rb

class ApiKeyValidator
  def initialize(app)
    @app = app
  end
  
  def call(env)
    request = Rack::Request.new(env)
    
    if request.has_header?('X-API-KEY') && request.get_header('X-API-KEY') == ENV['API_KEY']
      return @app.call(env)
    end
    
    [401, {'Content-Type' => 'text/plain'}, ['Unauthorized']]
  end
end