from django.contrib.contenttypes.models import ContentType

from django.dispatch import dispatcher

from django.db.models import get_apps, get_models, signals

from django.utils.encoding import smart_unicode

def update_contenttypes(app, created_models, verbosity=2):

    """

    Creates content types for models in the given app, removing any model

    entries that no longer have a matching model class.

    """

    ContentType.objects.clear_cache()

    content_types = list(ContentType.objects.filter(app_label=app.__name__.split('.')[-2]))

    app_models = get_models(app)

    if not app_models:

        return

    for klass in app_models:

        opts = klass._meta

        try:

            ct = ContentType.objects.get(app_label=opts.app_label,

                                         model=opts.object_name.lower())

            content_types.remove(ct)

        except ContentType.DoesNotExist:

            ct = ContentType(name=smart_unicode(opts.verbose_name_raw),

                app_label=opts.app_label, model=opts.object_name.lower())

            ct.save()

            if verbosity >= 2:

                print "Adding content type '%s | %s'" % (ct.app_label, ct.model)

    # The presence of any remaining content types means the supplied app has an

    # undefined model and can safely be removed, which cascades to also remove

    # related permissions.

    for ct in content_types:

        if verbosity >= 2:

            print "Deleting stale content type '%s | %s'" % (ct.app_label, ct.model)

        ct.delete()

def update_all_contenttypes(verbosity=2):

    for app in get_apps():

        update_contenttypes(app, None, verbosity)

dispatcher.connect(update_contenttypes, signal=signals.post_syncdb)

if __name__ == "__main__":

    update_all_contenttypes()