Access Mongodb's 'db' in routers, NodeJS/Express - node.js

Question

I'm unable to export the db object for using in my routers (controller). Heres the file where i connect to the database and attempt to export db object:
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
database = db;
module.exports = database;
});
and where i try using it in one of my routers:
var db = require('../path/to/file/above');
// Redirect to application
router.get('/', function(req, res, next) {
try {
db.close();
} catch (err) {
console.log(err);
}
res.render('index',{});
});
"console.log(err)" says "db.close() is not a function".
Q: How do i properly export the db object so i can use it in my routers?

Answer 1

i think there is some problem with your module.exports try this
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
function connectMongo(cb){
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
cb(db);
});
}
module.exports = connectMongo;

Answer 2

You can use mongoskin to access the mongodb and can export the db object.
e.g.
var mongo = require('mongoskin');
var url = 'mongodb://localhost:27017/database';
var db = mongo.db(url, {native_parser:true});
module.exports = db;
And, in your router,
var db = require('../path/to/file/above');
// Redirect to application
router.get('/', function(req, res, next) {
try {
//some db operations
} catch (err) {
console.log(err);
}
res.render('index',{});
});
Other solution is to pass the callback as suggested by #Asif.

Answer 3

This is what my database file (database.js) ended up to be:
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
var express = require('express');
var app = express();
// Connection URL
var url = 'mongodb://localhost:27017/database';
// Use connect method to connect to the server
var database;
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
database = db;
});
// Returns DB object when called
module.exports.get = function() {
return database;
}
and using it like this (note that you have to call the get function in a router.get() for example, calling it directly won't work since the connection won't be open yet):
var database = require('./database.js');
var assert = require('assert');
var express = require('express');
var router = express.Router();
// Redirect to application
router.get('/', function(req, res, next) {
var db = database.get();
// Mongo Query here
res.render('index',{});
});