Mixins are the essence of DRY code in class-based views. Like model mixins, a view mixin takes advantage of Python's multiple inheritance to easily reuse chunks of functionality. They are often parent-less classes in Python 3 (or derived from object in Python 2 since they are new-style classes).
Mixins intercept the processing of views at well-defined places. For example, most generic views use get_context_data to set the context dictionary. A derived class or mixin can insert an additional context variable, such as feed that contains a user's feed of posts. Here is how that mixin would look like:
class FeedMixin:
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context["feed"] = models.Post.objects.viewable_posts(
self.request.user)
return context
The get_context_data...
