Question

我想将node.js文件拆分为多个文件，如：

user.js用于处理用户数据库CRUD
group.js用于处理组数据库CRUD
database.js用于初始化数据库
restful.js初始化express.js

我关心的是这是一种普遍的还是良好的做法。

以下文件分割后：

app.js

require('./restful');
require('./database');

config.js

module.exports = function(){

database :{
   username: "mark",
   password: "pass",
   host: "127.0.0.1",
   port: "27017",
   name: "mydb"
};

database.js

var config = require('./config');
var mongodb = require('mongodb');

var url = 'mongodb://'+ config.database.username+ ':' + config.database.password + '@' + config.database.host + ':' + config.database.port + '/' + config.database.name;

var Database = function() {
    var db;

    // always return the singleton instance, if it has been initialised once already.
    if (Database.prototype._singletonInstance) {
        return Database.prototype._singletonInstance;
    }    

    this.getDatabase = function() {
         return db;
    }

    this.get = this.getDatabase;

    mongodb.MongoClient.connect(url, function(err, result) {
        if(err || result === undefined || result === null) {
              throw err;
        } else {
              db = result;
        }
    });    

    Database.prototype._singletonInstance = this;    
};

new Database();

console.log('MongoDb set up OK!');

exports.Database = Database;
};

restful.js

var express = require('express');
var bodyParser = require('body-parser');
var restful_express = express();
restful_express.use(bodyParser());

var allowCrossDomain = function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET, POST');
    res.header('Access-Control-Expose-Headers', 'token');
    res.header('Access-Control-Allow-Headers', 'Content-Type, X-XSRF-TOKEN, Last-Event-ID, Content-Language, Accept-Language, Accept');
    res.header('X-XSS-Protection', 0);
    next();
}

restful_express.use(allowCrossDomain);

restful_express.listen(process.env.PORT || 7272, function(err) {
       winlog.info('ExpressJs listening at 7272');    
});  

var Restful = function() {

    // always return the singleton instance, if it has been initialised once already.
    if (Restful.prototype._singletonInstance) {
        return Restful.prototype._singletonInstance;      
    }    

    this.getRestful = function() {
         return restful_express;       
    }

    Restful.prototype._singletonInstance = this;      
};

new Restful();

console.log('Express.js Restful set up OK!');

exports.Restful = Restful;

user.js的

var config = require('./config');
var database = require('./database');
var db = database.Database();
var restful = require('./restful').Restful().getRestful();

module.exports = function(){

    restful.get('/getUser/:email', function(req, res) {

            db.get().collection("user").findOne({email:req.param('email')}, function(err, result) {

                   if(result) {          
                      res.send({name:result.name});
                   } else {
                      res.statusCode = 400;
                      res.send({msg:'Email not found'});         
                   }
            });
    });
});

group.js

var config = require('./config');
var database = require('./database');
var db = database.Database();
var restful = require('./restful').Restful().getRestful();

module.exports = function(){

    restful.get('/getGroup/:name', function(req, res) {

            db.get().collection("group").findOne({name:req.param('name')}, function(err, result) {

                   if(result) {                        
                      res.send({name:result.name});  
                   } else {
                      res.statusCode = 400;
                      res.send({msg:'Group not found'});         
                   }
            }); 
    });

});

所以database.js可以简化为：

var config = require('./config');
var mongodb = require('mongodb');
var db;
var url = 'mongodb://'+ config.database.username+ ':' + config.database.password + '@' + config.database.host + ':' + config.database.port + '/' + config.database.name;

module.exports = function(){
    initDb : function () {
        mongodb.MongoClient.connect(url, function(err, result) {
            if(err || result === undefined || result === null) {
                  throw err;
            } else {
                  db = result;
            }
        });         
    },

    getDb : function () {
        if(db === null || db === undefined) {
            this.initDb();
        }   
        return db;
    }
};

Answer 1

这只是一种绝对合法的方式。但是相当复杂。

module默认为单身。无论您拨打require('some_module');多少次，它的脚手架代码只执行一次。在REPL中尝试以下代码

//index.js
var i = 0;
i ++;
exports.show = function(){
   return i;
};
exports.increment = function(){  
   return i++;
};

然后在REPL中

> var one = require('./index.js');
> one.show();
  1
> var two = require('./index.js');
> two.show();
  1 
> one.increment();
  2
> two.show();
  2

在多个node.js文件中使用mongodb连接或express.js的正确方法

1 个答案: