在BAE中使用mongoose操作mongodb
在BAE中使用mongoose操作mongodb
几乎网上所有的使用mongoose的例子都是长连接的方式,因为nodejs本身机制的关系,使用长连接一定程度上会提高性能,但是bae的免费mongodb不支持长链接,之前也有很多人做了尝试,比如断开后捕捉错误,然后自动重连的方式,现在来看都不太成功,于是还是中规中矩的使用短链接的方式来做吧,这里实现了一个连接打开和关闭的托管。
mongoosekeeper.js
'use strict';
var mongoose = require('mongoose');
var util = require("util");
function MongooseKeeper() {
this.db = mongoose.createConnection();
this.open_count = 0;
}
MongooseKeeper.prototype.config = function(conf) {
// body...
var options = {
db: { native_parser: true },
server: {
poolSize:4
}
};
var constr = "";
if(process.env.MONGO_DB_STR){
constr = process.env.MONGO_DB_STR ;
}
else{
//'mongodb://user:pass[@localhost](/user/localhost):port/database'
constr = util.format('mongodb://%s:%s@%s:%d/%s', conf.userid,conf.password,conf.host,conf.port,conf.database);
}
this.dbUri = constr;
this.options = options;
}
MongooseKeeper.prototype.open =function() {
this.open_count++;
if(this.open_count ==1 && this.db.readyState == 0)
{
this.db.open(this.dbUri,this.options,function() {
// body...
console.log("db opened");
});
}
}
MongooseKeeper.prototype.close =function() {
this.open_count--;
if(this.open_count == 0 )
{
this.db.close(function(){
console.log("db closed");
});
}
}
MongooseKeeper.prototype.use = function(action,callback) {
//OPEN
var self = this;
self.open();
action.call(null,function() {
//CLOSE
console.log("正在访问的数据库请求量"+self.open_count);
self.close();
callback.apply(null, arguments);
//DONE
self =null;
})
};
exports = module.exports = new MongooseKeeper();
首先在应用启动的时候,比如在app.js中,配置数据连接的等信息
// 引用mongoosekeeper
var mongoosekeeper = require('./lib/mongoosekeeper');
// 调用更新配置,这里的配置可以去读某个json
mongoosekeeper.config({
"host": "192.168.57.186",
"database": "dbname",
"userid":"userid",
"password":"123456",
"port":27017
});
定义Model
'use strict';
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var mongokeeper = require('../lib/mongoosekeeper');
var articleModel = function () {
var articleSchema = new Schema({
content : String, // 发布内容
type : Number, //
pictures : [{url:String,width:Number,height:Number}], // 配图
thumbnails : [{url:String,width:Number,height:Number}], // 缩略图
tags : [String], // 标签
author : String, // 发布人账号
author_name : String, // 发布人名称
create_date : { type: Date, default: Date.now }, //创建时间
meta : {
votes : Number, //顶
favs : Number //收藏
}
});
//因为使用了createConnection 这里要使用mongokeeper.db.model
//而不是mongoose.model
return mongokeeper.db.model('article', articleSchema);
};
module.exports = new articleModel();
在调用model的时候,使用 mongoosekeeper.use
方法包装实际的调用即可
var express = require('express'),
router = express.Router(),
mongoosekeeper = require('../lib/mongoosekeeper'),
articleModel = require('../models/articleModel');
/* GET home page. */
router.get('/', function(req, res) {
mongoosekeeper.use(queryArticle,function(err,list){
if(err){
throw err;
}
else{
res.render('index',{data:list});
}
});
});
//proxy 参数即为mongoosekeeper.use的第二个参数
function queryArticle(proxy){
var search = {} ; //获取所有文章
var query = articleModel.find(search).limit(25);
query.sort('-create_date');
query.exec(proxy);
}
module.exports = router;