Question

Is it possible to get a signed in django user (that calls model’s delete method) in a callback connected to pre_delete signal?

Answer 1

The pre_delete signal doesn’t pass the request instance, but you can add a decorator, that adds it, and to use that decorator on a view, which deletes the specified Model.

Assuming that this is the callback function:

def pre_delete_cb(sender, instance, using, **kwargs):
    pass

which is being added in the decorator:

from django.db.models.signals import pre_delete
from functools import wraps
from django.utils.decorators import available_attrs

def pre_delete_dec(cb, sender):
    def decorator(view_func):
        @wraps(view_func, assigned=available_attrs(view_func))
        def _wrapped_view(request, *args, **kwargs):
            cb.request = request  # here we add the request to the callback function
            pre_delete.connect(cb, sender=sender)  # and connecting the real pre_delete to the callback
            return view_func(request, *args, **kwargs)
        return _wrapped_view
    return decorator

And use the decorator on the view in the way you call it – instead of pre_delete.connect(pre_delete_cb, MyModel), use:

@pre_delete_dec(pre_delete_cb, MyModel)
def myview(request):

and then in the callback you’ll have access to the request as:

def pre_delete_cb(sender, instance, using, **kwargs):
    current_user = pre_delete_cb.request.user

You can add this on global level, not just per view – using a Middleware:

from django.db.models.signals import pre_delete

def pre_delete_cb(sender, instance, using, **kwargs):
    current_user = pre_delete_cb.request.user

class PreDeleteMiddleware(object):
    def process_view(self, request, view_func, view_args, view_kwargs):
        pre_delete_cb.request = request
        from myapp.models import MyModel
        pre_delete.connect(pre_delete_cb, sender=MyModel)