mptt_tags.py 文件源码

def render(self, context):
        # Let any VariableDoesNotExist raised bubble up
        args = [self.node.resolve(context)]

        if self.foreign_key is not None:
            app_label, model_name, fk_attr = self.foreign_key.split('.')
            cls = apps.get_model(app_label, model_name)
            if cls is None:
                raise template.TemplateSyntaxError(
                    _('drilldown_tree_for_node tag was given an invalid model: %s') %
                    '.'.join([app_label, model_name])
                )
            try:
                cls._meta.get_field(fk_attr)
            except FieldDoesNotExist:
                raise template.TemplateSyntaxError(
                    _('drilldown_tree_for_node tag was given an invalid model field: %s') % fk_attr
                )
            args.extend([cls, fk_attr, self.count_attr, self.cumulative])

        context[self.context_var] = drilldown_tree_for_node(*args)
        return ''