hnhzServer/node_modules/quick-pomelo/lib/utils/dispatcher.js

// Copyright 2015 rain1017.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License. See the AUTHORS file
// for names of contributors.

'use strict';

exports.hashDispatch = function(id, servers){
    if(servers.length === 0){
        return;
    }

    if(id === null || id === undefined){
        return servers[0];
    }

    if (typeof(id) !== 'string') {
        id = String(id);
    }
    var md5 = require('crypto').createHash('md5').update(id).digest('hex');
    var hash = parseInt(md5.substr(0, 8), 16);

    return servers[hash % servers.length];
};