My custom middleware class seems to be skipping the process_exception stage during the response cycle
from django.utils.deprecation import MiddlewareMixin
class MyMiddleware(MiddlewareMixin):
def process_request(self, request):
print("Request!")
def process_response(self, request, response):
print("Response!")
return response
def process_exception(self, request, exception):
print("Exception!")
Middleware configured....
DJANGO_MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'corsheaders.middleware.CorsMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'debug_toolbar.middleware.DebugToolbarMiddleware',
]
LOCAL_MIDDLEWARE = [
'path.to.MyMiddleware',
]
MIDDLEWARE = DJANGO_MIDDLEWARE + LOCAL_MIDDLEWARE
and buried in my view code:
def some_view(request):
...
raise Exception("foo")
However when I hit the url I get this in the console log:
Request!
Internal Server Error: /my/url/
Traceback (most recent call last):
... long traceback ...
File "/path/to/my/views.py", line 184, in some_view
raise Exception("foo")
Exception: foo
ERROR django.request 2019-01-24 11:50:48,270 [exception.py handle_uncaught_exception 118] Internal Server Error: /my/url/
Traceback (most recent call last):
... long traceback ...
File "/path/to/my/views.py", line 184, in some_view
raise Exception("foo")
Exception: foo
Response!
As you can see, process_exception isn't called at all, process_request and process_response both. And for some reason the exception traceback is shown twice before my middleware's process_response is even hit. The response that is passed to process_response for my middleware is a standard Django 500 debug page suggesting that the exception has been handled already, but I was under the impression that having my middleware as the last in the list meant it should be the first to be accessed for the response cycle?
EDIT So on further playing, looks like this is somehow related to DjangoDebugToolbar, when I disable that and remove the middleware my middleware works fine. I'm puzzled by that because my middleware should be firing first.
EDIT 2 Specifically it appears to be the profiling panel? commenting it out fixes the issue... how bizzare
