def call(env)
      return receive(env) if env["PATH_INFO"] == RECEIVE_PATH
      return retrieve(env) if env["PATH_INFO"] == RETRIEVE_PATH
      @app.call(env)
    end
def call(env)
      return receive(env) if env["PATH_INFO"] == RECEIVE_PATH
      return retrieve(env) if env["PATH_INFO"] == RETRIEVE_PATH
      @app.call(env)
    end
Create a new instance of the middleware.

 @param [#call] app the next rack application in the chain.
 @param [Hash] options
 @option options [String] :store the file where the middleware
   will store the received PGTs until they are retrieved.

 Handles a single request in the manner specified in the class
 overview.

 @param [Hash] env the rack environment for the request.

 @return [Array] an appropriate rack response.