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Django Class Based View: checking an object in dispatch

Is there an established way to validate an object in dispatch without additional call to the database when self.get_object()

called later in get / post?

Here's what I have so far (modified slightly for this question):

class CourseUpdateView(UpdateView):
    def dispatch(self, request, *args, **kwargs):

        self.request = request
        self.kwargs = kwargs
        self.object = self.get_object()

        if self.object.is_online:
            messages.warning(request, "Sorry this one can't be updated")
            return redirect("course:detail", pk=self.kwargs['pk'])

        # this is going to call self.get_object again isn't it?
        return UpdateView.dispatch(self, request, *args, **kwargs)
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1 answer


You can cache the result get_object()

.

Here's a trivial example:



class CourseUpdateView(UpdateView):
    # [...] your dispatch method

    def get_object(self):
        # it doesn't matter how many times get_object is called per request
        # it should not do more than one request
        if not hasattr(self, '_object'):
            self._object = super(CourseUpdateView, self).get_object()
        return self._object
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