Routing

Routing Hello World

The main app file loads the routes file where routes are defined.

app.js

var express = require('express');
var app = express();

app.use('/', require('./routes'));

app.listen('3000');

routes.js

var router = require('express').Router();

router.get('/', function(req, res) {
    res.send('Hello World!');
});

module.exports = router;

Routing middleware

Middleware is executed prior to the route execution and can decide whether to execute the router according to the URL.

var router = require('express').Router();

router.use(function (req, res, next) {
    var weekDay = new Date().getDay();
    if (weekDay === 0) {
        res.send('Web is closed on Sundays!');
    } else {
        next();
    }
})

router.get('/', function(req, res) {
    res.send('Sunday is closed!');
});

module.exports = router;

Specific middleware can also be sent to each router handler.

var closedOnSundays = function (req, res, next) {
    var weekDay = new Date().getDay();
    if (weekDay === 0) {
        res.send('Web is closed on Sundays!');
    } else {
        next();
    }
}

router.get('/', closedOnSundays, function(req, res) {
    res.send('Web is open');
});

router.get('/open', function(req, res) {
    res.send('Open all days of the week!');
});

Multiple Routes

The main app file loads any routes files in which you would like to define routes. To do so we need the following directory structure: app.js routes/index.js routes/users.js

app.js

var express = require('express');
var app = express();

app.use('/', require('./routes/index'));
app.use('/users', require('./routes/users'))

app.listen('3000');

routes/index.js

var router = require('express').Router();

router.get('/', function(req, res) {
    res.send('Index Page');
});

router.get('/about', function(req, res) {
    res.send('About Page');
});

module.exports = router;

routes/users.js

var router = require('express').Router();

router.get('/', function(req, res) {
    res.send('Users Index Page');
});

router.get('/list', function(req, res) {
    res.send('Users List Page');
});

module.exports = router;

Running $ node app.js there should now be pages at the following urls:

localhost:3000/ - Displays “Index Page”
localhost:3000/about - Displays “About Page”
localhost:3000/users - Displays “Users Index Page”
localhost:3000/users/list - Displays “Users List Page”