Passing Database connection

Question

I wanted to open Database (Mongo) connection only once when I start application and share the same connection across the application. What am doing as part of app.js is

Creating connection

var dbConnection = mongoose.createConnection(config.database.address, config.database.dbName, config.database.port);

passing dbConnection in every route call

require('./services/MasterServices')(app , dbConnection); 

Is it right approach or anything wrong here?

• Matt Ball: Does this code work for you, or are you having problems with it?
• Siva: I do not have any problem, I'm asking if something wrong with the design or any better approach available there.

Answer 1

You can use the connect function, which returns the default connection.

Just add mongoose.connect('mongodb://username:password@host:port/database'); whenever you need it.

See http://mongoosejs.com/docs/connections.html

• Siva: Hi, So I should create connection in app.js and use connect method (in different class) to get connection reference?

Answer 2

if you have a module which looks after your db interaction, nodejs returns singleton objects for your module. This means you can create a connection in your module:

var connection mongoose. createConnection(); //only ever set up once. The first time it is required
exports.getConnection = function (cb){
 if(! connection) {
 connection = mongoose.createConnection();
 cb(undefined,connection);
 }
 else cb(undefined, connection);
};

Just an option.

Answer 3

You could separate the connection into a file like "db.js", and then require it when necessary. So for example:

// db.js
var mongoose = require('mongoose'),
 config = require('./config.js');
module.exports = mongoose.createConnection(
 config.database.address, config.database.dbName, config.database.port);

And then in your routes, you might do something like:

// route.js
var db = require('./db.js');