Making it easier to customise models saved by the admin (e.g. add an "updated_by" field)

[Simon Willison]

A very common requirement for customising the admin is to
automatically update a created_by or updated_by field with the user
object that made changes to an object. This is currently way harder
than it should be: http://www.djangosnippets.org/snippets/903/

That's not elegant at all - it involves hiding form fields with
JavaScript and cramming extra data in to form.cleaned_data before it
is processed by the regular admin flow.

We can definitely do this better by providing a new customisation
hook. I've added my first attempt as a ticket here:

http://code.djangoproject.com/ticket/8005

It's not quite right yet but it's a reasonable start. Here's the
resulting ModelAdmin subclass code:

class ArticleAdmin(admin.ModelAdmin):

def save_model_add(self, request, form, formsets):
new_object = form.save(commit=False)
new_object.created_by = request.user
new_object.updated_by = request.user
new_object.save()

if formsets:
for formset in formsets:
formset.instance = new_object
formset.save()

return new_object

def save_model_change(self, request, form, formsets):
new_object = form.save(commit=False)
new_object.updated_by = request.user
new_object.save()

if formsets:
for formset in formsets:
formset.save()

return new_object

The formsets stuff needs to be separated out to avoid unnecessary code
duplication, but I think it's the right general approach. Thoughts?

[Julien Phalip]

That looks good, but it would be cool (and maybe simpler) to have
pre_save and post_save hooks. For example:

class ArticleAdmin(admin.ModelAdmin):

def pre_save(self, request, instance, add):
if add:
instance.created_by = request.user
instance.updated_by = request.user

Just a thought...

[Brian Rosner]

On Mon, Jul 28, 2008 at 7:29 AM, Simon Willison <si...@simonwillison.net> wrote:
> The formsets stuff needs to be separated out to avoid unnecessary code
> duplication, but I think it's the right general approach. Thoughts?

Based on the patches on the ticket I think this is a good route.
However, if we do the main form we must also do the formsets. They too
can work with save(commit=False) along with a formset.save_m2m()
method. This is also something that has seen several tickets before.
Specifically [1] which requires this re-factoring to make it possible.

[1]: http://code.djangoproject.com/ticket/5780

--
Brian Rosner
http://oebfare.com

[Joseph Kocherhans]

I've thought about this quite a bit, and it's essentially the approach
I was taking, so +1

I also wanted to add a save_formset method to the InlineAdmin class,
but the details turned out to be a little too tricky to work out in
the hour or so I had to spend on it.

Joseph