Building Response object is a common way to return information from URL handler back to web framework for returning to client:
Django: https://docs.djangoproject.com/en/1.7/ref/request-response/#httpresponse-objects
Flask: http://werkzeug.pocoo.org/docs/0.9/wrappers/#werkzeug.wrappers.Response
Bottle: http://bottlepy.org/docs/dev/tutorial.html#tutorial-response
webapp2/WebOb: http://webapp-improved.appspot.com/api/webapp2.html#webapp2.Response