How to reuse mongodb connection in node.js

Question

I\'m using node-mongodb-native driver with mongodb to write a website.

I have a question about how to open mongodb connection once, then use it in collection name us

Answer 1

You can connect once, and then reuse it as many times as you want:

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);
    });
  }
};

And then reuse it:

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({ ...
});