Django snippets

def owner_required(Model=None):
    """
    Usage:
    
    @permission_required('blogs.change_entry')
    @owner_required(Entry)
    def manage_entry(request, object_id=None, object=None):
    
    @permission_required('blogs.delete_entry')
    @owner_required()
    def entry_delete(*args, **kwargs):
        kwargs["post_delete_redirect"] = reverse('manage_blogs')
        return delete_object(*args, **kwargs)
    """
    def _decorator(viewfunc):
        def _closure(request, *args, **kwargs):
            user = request.user
            grant = False
            model = Model
            mod_edit = False
            if 'object_id' in kwargs:
                object_id = int(kwargs['object_id'])
                if model:
                    mod_edit = True
                elif 'model' in kwargs:
                    model = kwargs['model']
                object = get_object_or_404(model, pk=object_id)
                
                if user.is_superuser:
                    grant = True
                else:
                    if user.__class__ == model:
                        grant = object_id == user.id
                    else:
                        names = [rel.get_accessor_name() for rel in user._meta.get_all_related_objects() if rel.model == model]
                        if names:
                            grant = object_id in [o.id for o in eval('user.%s.all()' % names[0])]
                if not grant:
                    response = render_to_response("403.html", {'object': object}, context_instance=RequestContext(request))
                    response.status_code = 403
                    return response
                if mod_edit:
                    kwargs['object'] = object
                
            response = viewfunc(request, *args, **kwargs)
            return response
        
        return wraps(viewfunc)(_closure)
    return _decorator