Middleware not executed by Django - django

Question

I am trying to include a middleware in a Django project, but it seems the middleware is not being executed by Django. The idea is to impersonate another user account when having app-administrator privileges.
The MIDDLEWARE section of my settings.py file looks like this:
MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'mird_project.monitor.middleware.impersonateMiddleware.ImpersonateMiddleware',
]
The middleware class looks like this:
from .models import Usuario
class ImpersonateMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
response = self.get_response(request)
return response
def process_request(self, request):
us_obj = Usuario.objects.all().filter(id_usuario=request.user.username).first()
tipo = us_obj.tipo.id_tipo
if tipo == "AD" and "__impersonate" in request.GET:
request.session['impersonate_id'] = request.GET["__impersonate"]
elif "__unimpersonate" in request.GET:
del request.session['impersonate_id']
if tipo == "AD" and 'impersonate_id' in request.session:
request.user = Usuario.objects.get(id_usuario=request.session['impersonate_id'])
return None
I inserted an assert False, request inside the process_request method so that it would abort execution with an exception and show me what request contained. It never even got executed, so I assume the middleware never gets executed. It doesn't throw any kind of error and the impersonation mechanism just displays the same administrator user in the site.
Any ideas why the middleware isn't being called?

Answer 1

It looks like you are mixing old and new style middleware APIs. The process_request() method is pre-Django 1.10 and won't get called automatically unless your middleware class uses MiddlewareMixin.
You'll need to call process_request() yourself from the __call__() method:
def __call__(self, request):
self.process_request(request) # Call process_request()
response = self.get_response(request)
return response
Or alternatively you could inherit from MiddlewareMixin so that process_request() is called by Django. However it would only make sense to do that if you need to make the middleware backwards compatible.