gistfile1.txt

module Middleware
  class VersionEndpoint
    def initialize(app)
      @app = app
    end

    def call(env)
      # Return the latest git-sha in ENV if the request is exactly the version endpoint.
      if env['PATH_INFO'] == '/version'
        if version = source_version
          [200, {'Content-Type' => 'text/plain'}, [version]]
        else
          [404, {}, ['Not Found']]
        end
      else
        @app.call(env)
      end
    end

    ##
    # Easier to test.
    def source_version
      ENV['SOURCE_VERSION']
    end
  end
end