How to access variables declared in main app.js in separate route files in node.js Express 2.5.5?

Question

I just started using a new version of Express (2.5.5) that by default creates a ./routes directory along with ./views and ./public

Inside of routes there is a index.js file which contains:

/*
 * GET home page.
 */

exports.index = function(req, res){
  res.render('index', { title: 'Express' })
};

by default (after running express from the commandline) and this is the routes section in the main app.js:

// Routes

app.get('/', routes.index);

I've set up a variable for a redis client in the main app.js:

var redis = require('redis'),
    db = redis.createClient();

and I was wondering how I could access the methods of db (and whatever other modules I require in app.js) in the files contained in ./routes

Answer 1

I really liked Jamund's solution, but I would extend the concept to this:

// db.js
var redis = require('redis');
module.exports = redis.createClient();

// index.js
var db = require(.'/db')

// whatever other file
var db = require(.'/db')
// do something with db
db.disconnect();

both db on index and other file would get the same instance of the redis client

Answer 2

Just call this at the top of your files. Requires are in a shared space, so you can re-require the file multiple times and it will always reference the same version. If you want to be fancy you can create your own db module that does something like this, to prevent double creating clients:

// db.js
var db 
var redis = require('redis')
exports.connect = function() {
  if (!db) db = redis.createClient()
  return db
}

exports.disconnect = function() {
  redis.quit()
  db = null
}


// index.js
var dbHelper = require(.'/db')
var db = dbHelper.connect()

// whatever other file
var dbHelper = require(.'/db')
var db = dbHelper.connect() // won't connect twice