Custom Error Pages for django-cms - django

Question

Supposedly a trivial task to server 403/404/500 error pages when using django-cms. Followed instructions on an old forum post to create this:
from cms.views import details
def custom_404(request):
response = details(request, 'page-not-found')
response.status_code = 404
return response
...
Urls.py has some lines like this:
handler404 = 'error_pages.views.custom_404'
...
From traceback django cms can't locate 404 page:
File "/home/username/.virtualenvs/venv/lib/python2.7/site-packages/cms/views.py", line 22, in _handle_no_page
raise Http404('CMS: Page not found for "%s"' % slug)
Http404: CMS: Page not found for "page-not-found"
Obviously added the required custom pages in django-cms with the slug: 'page-not-found'. Am I missing something obvious? Running on production server with debug=False. Running django-cms 2.4.2 (edit)
Perhaps it is better to just serve plain ol' error messages with hardcoded stylesheets?

Answer 1

After walking into countless walls over-thinking the issues, I just went with using the basic 403/404/500 handlers:
from django.utils.functional import curry
from django.views.defaults import *
handler500 = curry(server_error, template_name='500.html')
handler404 = curry(page_not_found, template_name='404.html')
handler403 = curry(permission_denied, template_name='403.html')
Created the templates for each error and put in absolute URLs for the stylesheets.
Problem solved. Wasted a bunch of time on something this trivial.

Answer 2

Here is a working (with DEBUG at True or False) 404 handler:
def handler404(request):
if hasattr(request, '_current_page_cache'):
delattr(request, '_current_page_cache')
response = details(request, '404')
response.status_code = 404
return response

Answer 3

EDIT / Easy solution
After more searching and thinking, an easier solution would be to create the default/standard 404.html, and therein use django-cms static placeholders...as easy as it gets!
Original (still working) Answer
After struggling updating my handler404 from an old cms project, and not finding any infos on this topic, and the accepted answer not being a real solution to the problem, I investigated and found a version that works in django-cms 3.4.
Worth noting
delete the _current_page_cache on the request
set request.current_page, or cms_tags will not use your 404 page and render empty
call the main cms details view for rendering the page
finally, call response.render() (as mentioned in comments)
The view
def handler404(request):
if hasattr(request, '_current_page_cache'): # we'll hit the cache otherwise
delattr(request, '_current_page_cache')
page = get_page_from_request(request, '404')
request.current_page = page # templatags seem to use this.
response = details(request, '404') # the main cms view
if hasattr(response, 'render'): # 301/302 dont have it!
response.render() # didnt know about this, but it's needed
response.status_code = 404 # the obvious
return response