Usage of Neo4j query with promise support to list all nodes a user has read access

gistfile1.js

/** Get available objects for current user */
server.get('/', function(req, res, next) {
    var username = req.authorization.basic.username;
    db_query([
        'START root=node(0)',
        'MATCH root-[:USERS_REF]->uroot-[:USER]->user-[:ACCEPT_READ]->n',
        'WHERE user.name = {username}',
        'RETURN n'
    ], {'username': username}).then(function(results) {
        var nodes = [];
        if( results && results.length ) {
            foreach(results).each(function(node) {
                var n = node.data;
                n._id = node.id;
                nodes.push(n);
            });
        }
        return next(nodes);
    }, function(err) {
        console.log('Neo4j query failed: ' + err);
        if(err.stack) console.log('stack: ' + err.stack);
        next(new restify.InternalError("Database query failed"));
    });

});

Error message:

Neo4j query failed: Error: key not found: user