Before class-based views, decorators were the only way to change the behavior of function-based views. Being wrappers around a function, they cannot change the inner working of the view, and thus effectively treat them as black boxes.

A decorator is function that takes a function and returns the decorated function. Confused? There is some syntactic sugar to help you. Use the annotation notation @, as shown in the following login_required decorator example:

@login_required
def simple_view(request):
    return HttpResponse()

The following code is exactly same as above:

def simple_view(request):
    return HttpResponse()

simple_view = login_required(simple_view)

Since login_required wraps around the view, a wrapper function gets the control first. If the user was not logged in, then it redirects to settings.LOGIN_URL. Otherwise, it executes simple_view as if it did not exist.

Decorators are less flexible than mixins. However, they are simpler. You can use both decorators and mixins in...