Django get_context_data

Question

Is it possible to 'skip' a code in get_context_data?

I have this parent class and wrote a child class everytime I context.update({}) I want to skip or not run certain key in the parent class, cause it is affecting the performance, especially when parent class has multiple queries inside them, and I don't want them in the child but certain key, val in the parent?

class Parent(ListView):
      ...
      context = super(Parent, self).get_context_data(**kwargs)
      queryset = Model.objects.all()
      context.update({
        "queries": querset,
        "grades": [1.75, 3.0]

      })
      return context

Class Child(Parent):
      context = super(Child, self).get_context_data(**kwargs)

      context.update({
        "migrate": True,

      })
      return context

here in the example Parent class inherits in ListView that has an object_list and I context.update "queries". When In Child class I want to skip/prevent from running in Child get_context_data the object_list and queries, I want only some of like 'grades' to be inherit in the child class, cause it is slowing specially when Parents queryset and object_list has thousands of queries.

Answer 1

You could use some kind of template method pattern for that, but with a default behavior within Parent instead of an abstract method.

class Parent(ListView):

    def get_context_data(self, **kwargs):
        context = super(Parent, self).get_context_data(**kwargs)
        queryset = self.get_custom_queryset()
        context.update({
            "queries": querset,
            "grades": [1.75, 3.0]

        })
        return context

    def get_custom_queryset(self):
        return Model.objects.all()


class Child(Parent):

    def get_context_data(self, **kwargs):
        context = super(Child, self).get_context_data(**kwargs)

        context.update({
            "migrate": True,
        })
        return context

    def get_custom_queryset(self):
        pass