Create permissions for proxy models

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import sys

from django.contrib.auth.management import _get_all_permissions
from django.contrib.auth.models import Permission
from django.contrib.contenttypes.management import update_contenttypes
from django.contrib.contenttypes.models import ContentType
from django.db import models
        
def create_proxy_permissions(app, created_models, verbosity, **kwargs):
    """
        Creates permissions for proxy models which are not created automatically
        by `django.contrib.auth.management.create_permissions`.
        see https://code.djangoproject.com/ticket/11154
        This method is inspired by `django.contrib.auth.managment.create_permissions`.
        
        Since we can't rely on `get_for_model' we must fallback to `get_by_natural_key`.
        However, this method doesn't automatically create missing `ContentType` so
        we must ensure all the model's `ContentType` are created before running this method.
        We do so by unregistering the `update_contenttypes` `post_syncdb` signal and calling
        it in here just before doing everything.
    """
    update_contenttypes(app, created_models, verbosity, **kwargs)
    app_models = models.get_models(app)
    # This will hold the permissions we're looking for as
    # (content_type, (codename, name))
    searched_perms = list()
    # The codenames and ctypes that should exist.
    ctypes = set()
    for model in app_models:
        opts = model._meta
        if opts.proxy:
            # We can't use `get_for_model` here since it doesn't return 
            # the correct `ContentType` for proxy models.
            # see https://code.djangoproject.com/ticket/17648
            app_label, model = opts.app_label, opts.object_name.lower()
            ctype = ContentType.objects.get_by_natural_key(app_label, model)
            ctypes.add(ctype)
            for perm in _get_all_permissions(opts):
                searched_perms.append((ctype, perm))
    
    # Find all the Permissions that have a content_type for a model we're
    # looking for. We don't need to check for codenames since we already have
    # a list of the ones we're going to create.
    all_perms = set(Permission.objects.filter(
        content_type__in=ctypes,
    ).values_list(
        "content_type", "codename"
    ))
    
    objs = [
        Permission(codename=codename, name=name, content_type=ctype)
        for ctype, (codename, name) in searched_perms
        if (ctype.pk, codename) not in all_perms
    ]
    Permission.objects.bulk_create(objs)
    if verbosity >= 2:
        for obj in objs:
            sys.stdout.write("Adding permission '%s'" % obj)
            
models.signals.post_syncdb.connect(create_proxy_permissions)
# see `create_proxy_permissions` docstring to understand why we unregister
# this signal handler.
models.signals.post_syncdb.disconnect(update_contenttypes)

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Comments

dkdndes (on March 1, 2012):

Hi,

I get in create_proxy_permissions Permission.objects.bulk_create(objs) AttributeError: 'PermissionManager' object has no attribute 'bulk_create'

Any idea?

Regards,

Peter

#

vbretsch (on March 2, 2012):

Hi Charettes,

i get the same error message 'dkdndes' described, when running a sync db command on a totally clean database.

Django code version is: (1, 3, 0, 'final', 0).

Am i doing something wrong?

Best regards, Volker

#

Nagyman (on March 5, 2012):

Unfortunately, bulk_create is new in the development version (1.4)

#

fspegni (on September 21, 2013):

Hi,

thanks for the useful snippet. I had to make 2 small modifications:

line 38:
    for perm in _get_all_permissions(opts, ctype):

line 30:
    app_models = django.db.models.get_models(app)

(in order to make the modified line 23 to work, I had to import django). Actually I don't know why your line 23 didn't work for me, but it raised me an exception like:

AttributeError: 'module' object has no attribute 'get_models'

to verify, in a django shell i run:

$ from django.db import models
$ models.get_models("foo")

and it executed it. nevertheless, the problem at line 38 seems a real bug (in django 1.5.1)

thanks again

#

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