How do I modularize my Node.js, express project? - node.js

Question

I have created a API for different webpages with some CRUD functionality for POST, GET, etc. methods using Node.js, express and mongoose. I also have a big app.js file, where my routing logic and functions for CRUD methods reside.
So in the app.js file, I have to do the CRUD functionality and routing logic for every model in my models folder. This is quite much for on file, how can I separate the CRUD logic for my models, and the routing logic? So that it still works as normal without hosing my file?
I was thinking to separate the CRUD into a "controllers" folder and the routing into the "routes" folder, but I dont know how exactly, and what to require at what place..
My app.js looks like:
var express = require('express');
var app = express();
var bodyParser = require("body-parser");
var morgan = require("morgan");
var routes = require('./routes');
var cors = require('cors')
//configure app
app.use(morgan('dev')); //log requests to the console
//configure body parser
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
var port = process.env.PORT || 5000;
//DATABASE SETUP
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/DNZ'); //connect to uor datbaase
//Handle the connection event, get reference to database.
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
console.log("DB connection alive");
});
//DNZ models live here
var FA = require('./models/DNZmodels/FA');
var FP = require('./models/DNZmodels/FP');
//ROUTES FOR OUR API
//=============================================================================
//create our router
var router = express.Router();
//middleware to use for all requests
router.use(function(req, res, next) {
// do logging
console.log('Something is happening.');
console.log('Today is:', Date())
next();
});
//test route to make sure everything is working (accessed at GET http://localhost:5000/DNZ/)
router.get('/', function(req, res) {
res.json({ message: 'Welcome to DNZ API!' });
});
//on routes that end in /FA
//----------------------------------------------------
router.route('/FA')
// create a FA (accessed at POST http://localhost:8080/DNZ/FA)
.post(function(req, res) {
//console.log(req.body);
//console.log(req.body.params);
//res.setHeader('Content-Type', 'application/json')
//res.send(JSON.stringify(req.body));
/*
var timestamp = req.body.Timestamp;
var prognostizierterBetriebswert = req.body.PrognostizierterBetriebswert;
var posFlexPot = req.body.posFlexPot;
var negFlexPot = req.body.negFlexPot;
var leistungsuntergrenze = req.body.Leistungsuntergrenze;
var leistungsobergrenze = req.body.Leistungsobergrenze;
var posGesEnergie = req.body.posGesEnergie;
var negGesEnergie = req.body.negGesEnergie;
var preissignal = req.body.Preissignal;
var dummy1 = req.body.Dummy1;
var dummy2 = req.body.Dummy2;
var dummy3 = req.body.Dummy3;
var fa = new FA({
Timestamp: timestamp,
Leistungsuntergrenze: leistungsuntergrenze,
Leistungsobergrenze:leistungsobergrenze,
PrognostizierterBetriebswert :prognostizierterBetriebswert,
posFlexPot: posFlexPot,
negFlexPot:negFlexPot,
posGesEnergie: posGesEnergie,
negGesEnergie: negGesEnergie,
Preissignal:preissignal,
Dummy1: dummy1,
Dummy2: dummy2,
Dummy3: dummy3
})
*/
//fa.name = req.body.name;
console.log("Erzeugen der Instanz FA..");
//console.log(Dummy1);
//res.send(JSON.stringify(timestamp));
// create a new instance of the FA model
var fa = new FA(req.body);
//SAVE the new instance
fa.save(function(err) {
if (err) {
console.log(err);
res.status(400);
res.send(err);
}
else {
console.log("Instanz FA in Datenbank erzeugt!");
res.status(200);
res.json({ message: 'FA-Instance created in datbase!' });
}
});
})
// get all the FAs (accessed at GET http://localhost:8080/DNZ/FA)
.get(function(req, res) {
FA.find(function(err, fas) {
if (err)
res.send(err);
res.json(fas);
});
});
//on routes that end in /FA/:FA_id
//----------------------------------------------------
router.route('/FA/:FA_id')
// get the bear with that id
.get(function(req, res) {
FA.findById(req.params.bear_id, function(err, fa) {
if (err)
res.send(err);
res.json(fa);
});
})
/*
* Athlete.
find().
where('sport').equals('Tennis').
where('age').gt(17).lt(50). //Additional where query
limit(5).
sort({ age: -1 }).
select('name age').
exec(callback);
*/
// update the bear with this id
.put(function(req, res) {
FA.findById(req.params.FA_id, function(err, fa) {
if (err)
res.send(fa);
//bear.name = req.body.name;
/*
FA.save(function(err) {
if (err)
res.send(err);
res.json({ message: 'FA updated!' });
});
*/
});
});
/*
// delete the bear with this id
.delete(function(req, res) {
FA.remove({
_id: req.params.bear_id
}, function(err, FA) {
if (err)
res.send(err);
res.json({ message: 'Successfully deleted' });
});
});
*/
//*************************************************************************
//CREATE FP ROUTE
//*************************************************************************
router.route('/FP')
// create a FA (accessed at POST http://localhost:8080/DNZ/FP)
.post(function(req, res) {
//res.setHeader('Content-Type', 'application/json')
console.log("Erzeugen der Instanz FP..");
// create a new instance of the FP model
var fp = new FP(req.body);
//SAVE the new instance
fp.save(function(err) {
if (err) {
console.log(err);
res.status(400);
res.send(err);
}
else {
console.log("Instanz FP in Datenbank erzeugt!");
res.status(200);
res.json({ message: 'FP-Instance created in datbase!' });
}
});
})
// get all the FAs (accessed at GET http://localhost:8080/DNZ/FA)
.get(function(req, res) {
FP.find(function(err, fps) {
if (err) {
console.log(err);
res.status(400);
res.send(err);
}
else {
//res.send("Willkommen auf /FP");
res.json(fps);
}
});
});
//REGISTER OUR ROUTES -------------------------------and listen to requests
app.use('/DNZ', router);
//START THE SERVER
//=============================================================================
// set static directories
app.use(express.static('./dist'));
app.use(cors());
// Define Routes
var index = require('./routes/index');
var users = require('./routes/users');
//Set up routes
routes.init(app)
//run
app.listen(port);
console.log('Listen on port: ' + port);
console.log('Server started, Listening on port ', port);

Answer 1

This is primarily opinion based, but I had the same thing a while back and developed a way to extract route/model logic from the main file, using the module require-dir
In my app.js
/**
* Process ALL routes from routes dir utilising require-dir
*
* Allows us to include an entire directory, without replicating
* code, creating similar routes on a per end-point basis. This
* nicely keeps all end-point routes separate.
*/
var routes = requireDir('./routes');
for(var x in routes) {
application.use('/', routes[x]); // here, application is your express server instance
}
Then create a directory called routes and add whatever, for instance routes/branding.js:
var expressFramework = require('express');
var Branding = require('../models/branding');
var responseHelper = require('../shared/responseHelper');
var responseStatusCodes = require('../shared/responseStatusCodes');
var responseMessages = require('../shared/responseMessages');
var queryHelper = require('../shared/queryHelper');
var routerObject = expressFramework.Router();
var branding = new Branding();
var responsehelper = new responseHelper();
var queryhelper = new queryHelper();
/**
* Endpoint /branding/{chain_id}/{site_id}
*/
routerObject.get('/branding/:chain_id/:site_id', function(req, res, next) {
var requiredFields = [
{
chain_id: true, where: 'path'
},
{
site_id: true, where: 'path'
}
];
if (!queryhelper.authenticateToken(req.headers.authorization)) {
responsehelper.sendResponse(res, responseStatusCodes.STATUS_UNAUTHORISED,
responseMessages.RESPONSE_AUTHENTICATION_FAILED);
return;
}
if (!queryhelper.validateQuery(req, requiredFields)) {
responsehelper.sendResponse(res, responseStatusCodes.STATUS_INVALID_QUERY_PARAMS,
responseMessages.RESPONSE_INVALID_QUERY_PARAMS);
return;
}
branding.getBranding(req, function(err, results, pagination) {
if (err) return next(err);
if (results.length >= 1) {
responsehelper.sendResponse(res, responseStatusCodes.STATUS_OK, results);
} else {
responsehelper.sendResponse(res, responseStatusCodes.STATUS_NOT_FOUND,
responseMessages.RESPONSE_NO_RECORDS_FOUND);
}
});
});
module.exports = routerObject;
The key point here, is that you eventually export the express Router object, which your application, can 'use'. You'll also notice, that branding uses an include var Branding = require('../models/branding'); - This contains all the logic, whereas the route contains the end point definitions only, a snippet:
var Promise = require('bluebird');
var db = require('../shared/db');
var queryHelper = require('../shared/queryHelper');
var schemas = require('../schemas/schemas');
var _ = require('lodash');
var serverSettings = require('../shared/coreServerSettings');
// Create new instance of mysql module
var connection = new db();
var queryhelper = new queryHelper();
var queryAndWait = Promise.promisify(connection.query);
// Branding Object
var Branding = function(data) {
this.data = data;
};
Branding.prototype.data = {};
/**
* Branding methods
*/
Branding.prototype.getBranding = function(req, callback) {
var params = [];
var queryFoundRows = `select FOUND_ROWS() as total`;
var query = `select
id
from
company
where
1=1
and chain_id=?`;
params.push(req.params.chain_id);
queryAndWait(query + '; ' + queryFoundRows, params).then(function(result) {
return Promise.map(result[0], function(row) {
var params = [];
var query = `select
*
from
location
where
1=1
and company_id=?
and site_id=?`;
params.push(row.id);
params.push(req.params.site_id);
return queryAndWait(query, params).then(function(result) {
return result[0];
});
}).then(function(payload) {
callback(null, payload);
}).catch(function(err) {
callback(err, null, null);
});
});
};
module.exports = Branding;
May not be exactly what you're after, but should provide a good start point. Good luck!

Answer 2

This topic is subjective however - it is important to take a standard and stick to it. The way I handled this was by creating a subfolder with a module (using module.exports) and an init function that constructs the express app.
For every route I have another module that has an init function which accepts the express application as a parameter and then adds the routes in there.
Main code file:
var Api = require('./API/index.js');
File /API/Index.js:
var express = require('express');
/* Instantiations */
var app = express();
module.exports = {
...
apply();
...
}
var route1 = require('./Routes/route1.js');
var route2 = require('./Routes/route2.js');
/* all additional routes */
var Routes = [route1,route2,...]
function apply(){
for(var i=0;i<Routes.length;i++){
Routes[i].init(app);
}
}
Then in API/Routes/route1.js and API/Routes/route2.js...
module.exports = {
init: function(app){
/* add your route logic here */
}
}
The benefits of this approach in my experience is that you can optionally choose to add or remove routes as needed and it provides a readable route-path via the file system which is handy in most modern text editors.