Question

I’m using Django’s class based DetailView generic view to look up an object for display. Under certain circumstances, rather than displaying the object, I wish to back out and issue a HTTP rediect instead. I can’t see how I go about doing this. It’s for when a user hits an object in my app, but without using the canonical URL. So, for example, on StackOverflow URLs take the form:

http://stackoverflow.com/<content_type>/<pk>/<seo_friendly_slug>

eg:

http://stackoverflow.com/questions/5661806/django-debug-toolbar-with-django-cms-and-django-1-3

You can actually type anything as the seo_friendly_slug part and it will redirect you to the correct canonical URL for the object looked up via the PK.

I wish to do the same in my DetailView. Retrieve the object, check that it’s the canonical URL, and if not redirect to the item’s get_absolute_url URL.

I can’t return an HttpResponseRedirect in get_object, as it’s expecting the looked up object. I can’t seem to return it from get_context_data, as it’s just expecting context data.

Maybe I just need to write a manual view, but I wondered if anyone knew if it was possible?

Thanks!

Ludo.

Answer 1

This isn’t a natural fit for DetailView. To do this you need to override the get method of BaseDetailView, which looks like:

class BaseDetailView(SingleObjectMixin, View):
    def get(self, request, **kwargs):
        self.object = self.get_object()
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)

So in your class you’d need to provide a new get method which did the URL check between fetching the object and setting up the context. Something like:

def get(self, request, **kwargs):
    self.object = self.get_object()
    if self.request.path != self.object.get_absolute_url():
        return HttpResponseRedirect(self.object.get_absolute_url())
    else:
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)

As you end up overriding so much of the functionality it becomes questionable whether it’s worth actually using a generic view for this, but youknow.