1. DJANGO
MIDDLEWARE
Creating a custom
@andreagrandi
Andrea Grandi

2. DJANGO ARCHITECTURE

3. AVAILABLE HOOKS
• process_request(request)
• process_view(
request, view_func, view_args, view_kwargs)
• process_exception(request, response)
• process_template_response(request, response)
• process_response(request, response)
(during a request)
(during a response)

4. THINGS TO KNOW WHEN YOU WRITE A MIDDLEWARE
• You need to write a class that just inherit from object
• The order in settings.py is important: middlewares are processed from top to
bottom during a request and from bottom to top during a response.
• You don’t need to implement all the available methods of a middleware. For
example you can just implement process_request and
process_template_response
• If you implement process_request and you decide to return an HttpResponse,
all the other middlewares, views etc… will be ignored and only your response
will be returned

5. EXAMPLE: BENCHMARKMIDDLEWARE
from datetime import datetime
class BenchmarkMiddleware(object):
def process_request(self, request):
request._request_time = datetime.now()
def process_template_response(self, request, response):
response_time = request._request_time - datetime.now()
response.context_data['response_time'] = abs(response_time)
return response

6. REFERENCES
Complete example:
https://github.com/andreagrandi/benchmark-middleware-example
Documentation:
• https://docs.djangoproject.com/en/1.8/topics/http/middleware/
• http://agiliq.com/blog/2015/07/understanding-django-middlewares/
• http://code.runnable.com/UrSGolK00ygpAAAQ/creating-a-custom-
middleware-for-python-and-django

7. Thanks!