call

# File actionpack/lib/action_dispatch/middleware/show_exceptions.rb, line 45
    def call(env)
      status, headers, body = @app.call(env)

      # Only this middleware cares about RoutingError. So, let's just raise
      # it here.
      # TODO: refactor this middleware to handle the X-Cascade scenario without
      # having to raise an exception.
      if headers['X-Cascade'] == 'pass'
        raise ActionController::RoutingError, "No route matches #{env['PATH_INFO'].inspect}"
      end

      [status, headers, body]
    rescue Exception => exception
      raise exception if env['action_dispatch.show_exceptions'] == false
      render_exception(env, exception)
    end