基于MongoSkin的Promise风格的NodeJS读写MongoDB

来源：互联网发布：滴滴大数据平台编辑：程序博客网时间：2024/05/20 06:36

Promise是一种异步编程的代码书写方式，和Async模块一样，都能提高代码的可读性和可维护性。Async封装的比Promise要好，但是灵活性特别是彻底的去CallBack化会比Promise要差一点。下面直接贴下源代码，注释很详细：

（1）数据库连接文件：dbConfig

/** * Created by apple on 2014/12/29. */var mongoskin = require('mongoskin');var db = null;var dbName = "yqbChat";/** * @function * @param collectionName * @returns {SkinCollection|null|*} */exports.getCollection = function (collectionName) {    if (!db) {        //连接本机mongodb ,使用帐号密码连接 mongoskin.db('username:password@服务器ip/数据库名        db = mongoskin.db('mongodb://127.0.0.1:27017/' + dbName + '?auto_reconnect=true&poolSize=3',            {numberOfRetries: 1, retryMiliSeconds: 500, safe: true, native_parser: true},            {socketOptions: {timeout: 5000}}        );    }    return db.collection(collectionName);};/** * @function 关闭数据库 */exports.dbClose = function(){    if (!db) {        db.close();    }};

(2)Model 层文件

/** * Created by apple on 2015/1/17. *//** 聊天室数据结构 * * //某两个用户对应的聊天室为一个集合，一个消息为一个文档 * @{singleChatRoomID} *  @_id 信息编号 *  @msgState 0-未读 1-已读 (int类型) *  @msgContent 消息内容 *  @msgSend 消息发送者的user_id *  @create_time * *///获取MongoDB的连接实例var moment = require('moment');var Q = require("q");//存放聊天室配置集合var singleChatRoomConfigInstance = null;//当前时间点var currentDateTime = moment().format("YYYY-M-D H:m:s");/** * @function 根据singleChatRoomID在singleChatRoomConfig文档中搜索配置信息 * @param singleChatRoomID 聊天室ＩＤ * @param callback　回调函数 如果为promise为空 * @param promise 如果存在promise，则callback为空 */exports.findSingleChatRoomByID = function (data) {    //根据singleChatRoomID搜索对应聊天室的配置，如果存在则返回聊天室配置，否则返回false    if (singleChatRoomConfigInstance == null) {        singleChatRoomConfigInstance = data.db.getCollection('singleChatRoomConfig');    }    var deferred = Q.defer();    console.log("[SingleChatRoomConfig->findSingleChatRoomByID]:开始根据聊天室ID查找配置数据！");    //查询    singleChatRoomConfigInstance.findOne({singleChatRoomID: data.singleChatRoomID}, function (error, result) {        if (typeof data.promise != undefined) {            if (!error) {                data.result = result;                //console.log(data);                deferred.resolve(data);            } else {                deferred.reject(error);            }        }        else {            callback(error, data);        }        //db.dbClose();    });    return deferred.promise;};/** * @function 在聊天室配置集合中插入新的集合 * @param singleChatRoomID * @param user_id_1 * @param user_id_2 * @param callback * @param promise */exports.insertSingleChatRoomByID = function (data) {    //根据singleChatRoomID搜索对应聊天室的配置，如果存在则返回聊天室配置，否则返回false    if (singleChatRoomConfigInstance == null) {        singleChatRoomConfigInstance = data.db.getCollection('singleChatRoomConfig');    }    var deferred = Q.defer();    console.log("[SingleChatRoomConfig->insertSingleChatRoomByID]:开始插入数据！");    //console.log(data);    singleChatRoomConfigInstance.insert(        {            singleChatRoomID: data.singleChatRoomID,            users: [data.user_id_1, data.user_id_2],            msgCount: 0,            createTime: currentDateTime        }, function (error, result) {            if (typeof data.promise != undefined) {                if (!error) {                    data.result = result;                    deferred.resolve(data);                } else {                    deferred.reject(error);                }                //db.dbClose();            }            else {                callback(error, result);                //db.dbClose();            }        }    );    return deferred.promise;};

（3）Test文件

/** * Created by apple on 2015/1/17. */var singleRoomConfigModel = require('../SingleRoomConfigModel');var model = require('../Model');var db = require('../db/dbConfig');var Q = require("q");/** * @function 测试在singleChatRoomConfig中查询是否存在某个聊天室的配置记录，不存在则创建 * @param singleChatRoomID *//**CallBack风格的函数*/function testFindAndInsertByID_CALLBACK(singleChatRoomID) {    //执行查询操作的回调函数    this.findSingleChatRoomByIDCallBack = function (error, result) {        console.dir("findSingleChatRoomByIDCallBack invoked!" + result);        //如果结果不为空，则查询所有未读信息        if (result != null) {        }        else        //如果结果为空，则建立一条新的数据返回未读信息条数为空        {            singleRoomConfigModel.insertSingleChatRoomByID(singleChatRoomID, 1, 2, this.insertSingleChatRoomByIDCallBack);        }    };    //执行插入操作的回调函数    this.insertSingleChatRoomByIDCallBack = function (error, result) {        if (error != null) {            console.log(result);        }        else {            console.error(error);        }    };    singleRoomConfigModel.findSingleChatRoomByID(singleChatRoomID, this.findSingleChatRoomByIDCallBack);}/**Promise风格的函数*/function testFindAndInsertByID_PROMISE(singleChatRoomID) {    var data = {        singleChatRoomID: singleChatRoomID,        promise: true,        db:db    };    singleRoomConfigModel.findSingleChatRoomByID(data).then(        /**         * @function 逻辑判断层，聊天室存在则返回聊天室信息，否则进入聊天室创建         * @param result         */        function (data) {            var deferred = Q.defer();            if(data) {                //console.log("聊天室存在，输出聊天室配置！");                deferred.resolve(data);            }            else{                //console.log("聊天室不存在，开始创建聊天室！");                //继续设置下一层的promise调用                deferred.reject(data);            }            return deferred.promise;        }        , model.errorHandler    ).then(        function(data){            //console.log("获取到了聊天室配置！");            var deferred = Q.defer();            deferred.resolve(data);            return deferred.promise;        },        singleRoomConfigModel.insertSingleChatRoomByID    ).done(        function(data){            //console.log("testFindAndInsertByID_PROMISE-完毕");            //console.log(data);            data.db.dbClose()        },        model.errorHandler    );}testFindAndInsertByID_PROMISE("1");

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