templateresponse

At times, you need to perform some postprocessing after a view has been rendered. It could be some serious work, in which case you’d better arrange for it to be carried over by a separate thread, a separate process or even a separate server, or it could be just a quick update of the database. In either case, you need to ensure that whatever has to be done does not influence the response.

Of course, in a manually  implemented view, rendering to the response need not be the last action. You can always write:

def my_view(request):
    do_some_work()
    response = render_to_response('my_view.html')
    do_extra_work()
    return response

But, when using a class-based generic view, you might be left wondering for a while, especially if you happen to focus too much on the wrong part of the documentation.

Turns out that the answer is quite simple and elegant. Class-based generic views return a new kind of response introduced in Django 1.3, the TemplateResponse, which provides a hook to perform extra work after the template has been rendered. Armed with that knowledge, you can easily write a generic mixin like this:

class PostprocessorMixin(object):
    def get(*args, **kwargs):
        resp = super(PostprocessorMixin, self).get(*args, **kwargs)
        resp.add_post_render_callback(self.postprocess)
        return resp

When you later need to perform extra work after rendering the response, mix this in your custom derived views and implement your postprocessing in postprocess.