如何在node.js中重用mongodb连接

Question

我将mongodb的node-mongodb-native驱动程序用于编写网站。

我有一个关于如何一次打开mongodb连接，然后在中的集合名称用户user.js和中的集合名称帖子中使用它的问题comment.js

我想在其中打开数据库连接db.js以为用户插入/保存数据并发布帖子

当前代码，我的 db.js

var Db = require('mongodb').Db,
    Connection = require('mongodb').Connection,
    Server = require('mongodb').Server;
module.exports = new Db(
    'blog', 
    new Server('localhost', Connection.DEFAULT_PORT, {auto_reconnect: true})
);

我曾经db.js在user.js如下

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

function User(user){
  this.name = user.name;
  this.password = user.password;
  this.email = user.email;
};

module.exports = User;

User.prototype.save = function(callback) {//save user information
  //document to save in db
  var user = {
      name: this.name,
      password: this.password,
      email: this.email
  };
  mongodb.close();
  //open mongodb database
  mongodb.open(function(err, db){
    if(err){
      return callback(err);
    }
    //read users collection
    db.collection('users', function(err, collection){
      if(err){
        mongodb.close();
        return callback(err);
      }
      //insert data into users collections
      collection.insert(user,{safe: true}, function(err, user){
        mongodb.close();
        callback(err, user);//success return inserted user information
      });
    });
  });
};

和 comment.js

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

function Comment(name, day, title, comment) {
  this.name = name;
  this.day = day;
  this.title = title;
  this.comment = comment;
}

module.exports = Comment;

Comment.prototype.save = function(callback) {
  var name = this.name,
      day = this.day,
      title = this.title,
      comment = this.comment;
  mongodb.open(function (err, db) {
    if (err) {
      return callback(err);
    }
    db.collection('posts', function (err, collection) {
      if (err) {
        mongodb.close();
        return callback(err);
      }
      //depend on name time and title add comment
      collection.findAndModify({"name":name,"time.day":day,"title":title}
      , [ ['time',-1] ]
      , {$push:{"comments":comment}}
      , {new: true}
      , function (err,comment) {
          mongodb.close();
          callback(null);
      });   
    });
  });
};

Answer 1

您可以连接一次，然后根据需要重复使用多次：

var mongodb = require('mongodb');
var events = require('events');
var event = new events.EventEmitter();
var access = new mongodb.Server(host, port, { });
var client = null;

new mongodb.Db('YOUR DATABASE', access, { safe: true, auto_reconnect: true }).open(function (err, c) {
  if (!err) {
    client = c;
    console.log('database connected');
    event.emit('connect');
  } else {
    console.log('database connection error', err);
    event.emit('error');
  }
});

exports.get = function(fn) {
  if(client) {
    fn(client);
  } else {
    event.on('connect', function() {
      fn(client);
    });
  }
};

然后重用它：

var db = require('./db');
var items;
db.get(function(client) {
  items = new mongodb.Collection(client, 'collection');
});

// then anywhere in your code
db.get(function() {
  // items.find({ ...
});