Django exception middleware: TypeError: object() takes no parameters

I'm using Django 1.10 and trying to catch all exceptions with exception middleware.

The code below causes an internal server error:

mw_instance = middleware(handler)
TypeError: object() takes no parameters

views.py

from django.http import HttpResponse

def my_view(request):
    x = 1/0 # cause an exception
    return HttpResponse("ok")
    

settings.py

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',
    'myproject.middleware.ExceptionMiddleware',  
    
]

middleware.py

from django.http import HttpResponse

class ExceptionMiddleware(object):
    def process_exception(self, request, exception): 
        return HttpResponse("in exception")

I have seen these https://stackoverflow.com/questions/39457381/object-takes-no-parameters-in-django-1-10 and other questions talking about middleware versus middleware_classes, but I'm not sure how that applies to this case, or what I'd actually need to change to fix the issue.

Since you are using the new MIDDLEWARE settings, your Middleware class must accept a get_response argument: https://docs.djangoproject.com/en/1.10/topics/http/middleware/#writing-your-own-middleware

You could write your class like this:

from django.http import HttpResponse

class ExceptionMiddleware(object):
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        return self.get_response(request)

    def process_exception(self, request, exception): 
        return HttpResponse("in exception")

You could also use the MiddlewareMixin to make your Middleware compatible with pre-1.10 and post-1.10 Django versions: https://docs.djangoproject.com/en/1.10/topics/http/middleware/#upgrading-pre-django-1-10-style-middleware

from django.http import HttpResponse
from django.utils.deprecation import MiddlewareMixin

class ExceptionMiddleware(MiddlewareMixin):
    def process_exception(self, request, exception):
        return HttpResponse("in exception")

in the newer version of Django, the middleware should be written like this

import datetime
from django.core.cache import cache
from django.conf import settings
from django.utils.deprecation import MiddlewareMixin

class ActiveUserMiddleware(MiddlewareMixin):

    def process_request(self, request):
        current_user = request.user
        if request.user.is_authenticated:
            now = datetime.datetime.now()
            cache.set('seen_%s' % (current_user.username), now, 
                           settings.USER_LASTSEEN_TIMEOUT)