[Django]-Adding new custom permissions in Django

If you want “manage.py migrate” to do everything (without calling syncdb –all). You need to create new permissions with a migration:

user@host> manage.py datamigration myapp add_perm_foo --freeze=contenttypes --freeze=auth

Edit the created file:

class Migration(DataMigration):

    def forwards(self, orm):
        "Write your forwards methods here."
        ct, created = orm['contenttypes.ContentType'].objects.get_or_create(
            model='mymodel', app_label='myapp') # model must be lowercase!
        perm, created = orm['auth.permission'].objects.get_or_create(
            content_type=ct, codename='mymodel_foo', defaults=dict(name=u'Verbose Name'))

This worked for me:

./manage.py update_permissions

It is a django-extensions thing.

You can connect to the post_migrate signal in order to update the permissions after migration. I use the following code, slightly modified from Dev with Passion and originally from django-extensions.

# Add to your project-level __init__.py

from south.signals import post_migrate

def update_permissions_after_migration(app,**kwargs):
    """
    Update app permission just after every migration.
    This is based on app django_extensions update_permissions management command.
    """
    from django.conf import settings
    from django.db.models import get_app, get_models
    from django.contrib.auth.management import create_permissions

    create_permissions(get_app(app), get_models(), 2 if settings.DEBUG else 0)

post_migrate.connect(update_permissions_after_migration)

When i runnning migration with following code

ct, created = orm['contenttypes.ContentType'].objects.get_or_create(model='mymodel',     app_label='myapp') # model must bei lowercase!
perm, created = orm['auth.permission'].objects.get_or_create(content_type=ct, codename='mymodel_foo')

I getting folloving error

File "C:\Python26\lib\site-packages\south-0.7.3-py2.6.egg\south\orm.py", line 170, in  __getitem__
raise KeyError("The model '%s' from the app '%s' is not available in this migration." % (model, app))
KeyError: "The model 'contenttype' from the app 'contenttypes' is not available in this migration."

To prevent this error, i modified the code

from django.contrib.contenttypes.models import ContentType
from django.contrib.auth.models import Permission

class Migration(DataMigration):

    def forwards(self, orm):
        "Write your forwards methods here."
        ct = ContentType.objects.get(model='mymodel', app_label='myapp') 
        perm, created = Permission.objects.get_or_create(content_type=ct, codename='mymodel_foo')
        if created:
            perm.name=u'my permission description'
            perm.save()