Django class based view mixins

mixin.py

# -*- coding: utf-8 -*-
from django.contrib.auth.decorators import login_required
from django.utils.cache import patch_response_headers
from django.utils.decorators import method_decorator
from django.views.decorators.cache import cache_page, never_cache
from django.views.decorators.csrf import csrf_exempt


class NeverCacheMixin(object):
    @method_decorator(never_cache)
    def dispatch(self, *args, **kwargs):
        return super(NeverCacheMixin, self).dispatch(*args, **kwargs)


class LoginRequiredMixin(object):
    @method_decorator(login_required)
    def dispatch(self, *args, **kwargs):
        return super(LoginRequiredMixin, self).dispatch(*args, **kwargs)


class CSRFExemptMixin(object):
    @method_decorator(csrf_exempt)
    def dispatch(self, *args, **kwargs):
        return super(CSRFExemptMixin, self).dispatch(*args, **kwargs)


class CacheMixin(object):
    cache_timeout = 60

    def get_cache_timeout(self):
        return self.cache_timeout

    def dispatch(self, *args, **kwargs):
        return cache_page(self.get_cache_timeout())(super(CacheMixin, self).dispatch)(*args, **kwargs)


class CacheControlMixin(object):
    cache_timeout = 60

    def get_cache_timeout(self):
        return self.cache_timeout

    def dispatch(self, *args, **kwargs):
        response = super(CacheControlMixin, self).dispatch(*args, **kwargs)
        patch_response_headers(response, self.get_cache_timeout())
        return response


class JitterCacheMixin(CacheControlMixin):
    cache_range = [40, 80]

    def get_cache_range(self):
        return self.cache_range

    def get_cache_timeout(self):
        return random.randint(*self.get_cache_range())

views.py

# -*- coding: utf-8 -*-
from django.views.generic.detail import DetailView


class ArticleView(CacheMixin, DetailView):
    cache_timeout = 90
    template_name = "article_detail.html"
    queryset = Article.objects.articles()
    context_object_name = "article"

got these mixins in a lib anywhere? :)

You shouldn't override dispatch, but the class method as_view()

See the docs, which have just been written and also the just-closed issue where we discussed it.

The reason you shouldn't override dispatch is because things break if dispatch doesn't always accept a compatible set of params

This is nice - but wouldn't it be better if the CacheControlMixin called cache_control() in the same way you call cache_page in CacheMixin? This enables things like setting cache_control(private=True, public=False) and other options that the cache_control header providers. The timeout is only one of many things the cache_control can set.

@pjrobertson I'm still confused - there seems to be two documented ways to make a login_required mixin:

• Overriding as_view
• Overriding dispatch

Is one of these examples incorrect?

What's the difference between CacheMixin and CacheControlMixin?, how could I clear the generated cache?. For example, would be nice to clear the cache when you're updating the article. Thank you in advance.

class CacheMixin(object):
    cache_timeout = 60

    def dispatch(self, *args, **kwargs):
        return cache_page(self.cache_timeout)(
            super(CacheMixin, self).dispatch)(*args, **kwargs)

Seems simpler. If get_cache_timeout is to allow be overwritten, maybe adding the argument request improves it usage. Nice list of mixins :)

You shouldn't override dispatch, but the class method as_view()

See the docs, which have just been written and also the just-closed issue where we discussed it.

The reason you shouldn't override dispatch is because things break if dispatch doesn't always accept a compatible set of params

I followed the link, and read the documentation, but they instruct and show one to decorate the dispatch method:
https://docs.djangoproject.com/en/2.2/topics/class-based-views/intro/#decorating-the-class
Are you sure about .as_view()?