Allow get_success_url to access self. object in DeletionMixin

[anonymous]

Let's say I have object with parent set and once object is deleted, browser should be redirected to parent page.

Expected way to work is:

url(r'^object/(?P<pk>\d+)/delete/$', DeleteView.as_view(model=Object, success_url='/parent/%(parent_id)d/'), name='object_delete')

This can be achieved by evaluating success_url first and then deleting object:

class DeletionMixin(object):
    """
    A mixin providing the ability to delete objects
    """
    success_url = None

    def delete(self, request, *args, **kwargs):
        self.object = self.get_object()
        success_url = self.get_success_url()
        self.object.delete()
        return HttpResponseRedirect(success_url)

    # Add support for browsers which only accept GET and POST for now.
    def post(self, *args, **kwargs):
        return self.delete(*args, **kwargs)

    def get_success_url(self):
        if self.success_url:
            return self.success_url % self.object.__dict__
        else:
            raise ImproperlyConfigured(
                "No URL to redirect to. Provide a success_url.")

[Preston Holmes]

To simplify and clarify a bit:

the get_success_url should be able to see self.object when it is called - and so should happen before the object is deleted.

Seems completely reasonable, and should be backwards compatible.

see ​https://docs.djangoproject.com/en/dev/internals/contributing/ regarding patch format requirements

[anonymous]

Attached patch doesn't address an issue properly.
Please take a look at pull request - ​https://github.com/django/django/pull/417

[Preston Holmes]

I have no idea why the % dict pattern was chosen - I'd prefer to make the code consistent for now - but not overtly document it.

pull is more complete than the attached patch - not sure if it is the same author - but if not please note the convention of letting one person work on a feature at a time.

Tests are needed - committer could take care of a brief release note

[Nick Sandford]

Added tests, pull request here: ​https://github.com/django/django/pull/663/.

[Simon Charette]

Assigning to myself since I'm planning to commit this.

[Simon Charette]

Added a new patch based on nxvl and slurms work with a release note.

Tests were rewritten because they were not failing without the DeletionMixin.delete fix since self.object.slug is still accessible after deletion. It's not the case with self.object.id.

Also fixed some badly indented code while I was there.

[Simon Charette]

Someone else should review the wording of the release note.

[Tim Graham]

I've tweaked the release note a bit and also added documentation of this in the docs.

[Simon Charette <charette.s@…>]

In a10f3908042a71ec5ef81bf76f0f278ca5e7a596:

Fixed #19044 -- Made DeletionMixin interpolate its success_url.

Thanks to nxvl and slurms for the initial patch, ptone for the review
and timo for the documentation tweaks.