How to redirect in a Generic View

问题

I am using a generic view to render my blog post item:

class PostUpdateView(UpdateView, LoginRequiredMixin):
    model = Post
    # etc

I have a model method on the Post model that results in a boolean True or False:

@property
def can_edit(self):
    return self.displays_set.count() == 0 

If can_edit is False for the Post object, how can I refactor the view to redirect from my UpdateView to a different DetailView?

回答1:

Override the dispatch method, and check obj.can_edit there. That way the object will be checked for get and post requests.

class PostUpdateView(LoginRequiredMixin, UpdateView):
    model = Post

    def dispatch(self, *args, **kwargs):
        obj = self.get_object()
        if not obj.can_edit:
            return redirect('/readonly-view/')

        return super().dispatch(*args, **kwargs)

With this solution, get_object() is called twice so there is a duplicate SQL query. However this is probably worth it to keep the code simple.

回答2:

I would say that override dispatch method is best solution,
but if you want to avoid extra database hit, then you need to override get and post methods

def get(self, request, *args, **kwargs):
    self.object = self.get_object()
    if not obj.can_edit:
        return redirect('/readonly-view/')

    return self.render_to_response(self.get_context_data())

def post(self, request, *args, **kwargs):
    self.object = self.get_object()
    if not obj.can_edit:
        return redirect('/readonly-view/')

    form = self.get_form()
    if form.is_valid():
        return self.form_valid(form)
    else:
        return self.form_invalid(form)

来源：https://stackoverflow.com/questions/57724022/how-to-redirect-in-a-generic-view