from roundup.rest import calculate_etag

def etag(node):
    # def calculate_etag(node, key, classname="Missing", node_id="0",
    #                   repr_format="json"):

    db_node = node._db.getclass(node._classname).getnode(node._nodeid)
    tag = calculate_etag(db_node,
                         node._db.config.WEB_SECRET_KEY)
    return tag

def init(instance):
    instance.registerUtil('etag', etag)