Redirect from Generic View DetailView in Django

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 ou

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.

Answer 2

Developing on Rolo's answer and comments, I came up with the following generic view to serve this purpose:

from django import http
from django.views import generic


class CanonicalDetailView(generic.DetailView):
    """
        A DetailView which redirects to the absolute_url, if necessary.
    """
    def get_object(self, *args, **kwargs):
        # Return any previously-cached object
        if getattr(self, 'object', None):
            return self.object
        return super(CanonicalDetailView, self).get_object(*args, **kwargs)

    def get(self, *args, **kwargs):
        # Make sure to use the canonical URL
        self.object = self.get_object()
        obj_url = self.object.get_absolute_url()
        if self.request.path != obj_url:
            return http.HttpResponsePermanentRedirect(obj_url)
        return super(CanonicalDetailView, self).get(*args, **kwargs);

This is used in the same manner as the normal DetailView, and should work for any model which implements get_absolute_url correctly.