Key Differences from HTTP.IncomingMessage

• url.parse not needed
• querystring.parse not needed

Query Parameters

// misc/req.params.js
var server = require('express')();

// example: GET /?foo=bar
server.get('/', function(req, res){
  res.send('foo is... ' + req.query.foo);
});

server.listen(3000);

Named Parameters

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

server.get('/:foo', function(req, res){
  res.send(':foo is... ' + req.params.foo);
});

server.listen(3000);

start/restaurants-server-1.js:

1. /restaurants/2 replies...
   'Restaurant 2: Taco Gong'

Hints:

var users = [
  { id: 1, name: 'Qian' },
  { id: 2, name: 'Zeynep'},
  { id: 3, name: 'Raisel'}
];
var qian = findById(users, 1);

Up Next: the response object

res.send

res.send('<h1>Sequoia\'s WebZone!</h1>');

res.send({ id: 1, name: 'Zeynep' });

res.send(new Buffer('Here is an octet-stream for you!'));

res.json

res.json([
  {id : 1, name : 'Sequoia'},
  {id : 2, name : 'Jackson'},
  {id : 3, name : 'Christine'}
]);

res.json(null)

res.json("<h1>Hello!</h1>");

start/restaurants-server-2.js

1. Update /restaurants/:id route to send json
2. /restaurants/ replies with all restaurants as json

res.status

res.status(204); // No Content

res.status(404)
   .send('Not Found');

///or perhaps

res.status(404)
   .json({error : 'Not Found'});

res.status(500)
   .sendFile('/var/www/shared/internal_error.html');

res.set

res.set('Content-Type', 'text/markdown');

res.set({
  'X-Powered-By' : 'Sequoia\'s #1 Web Framwork!/v2.5',
  'X-Favorite-Animal': 'Hamster',
  Pragma : 'no-cache'
});

res.redirect

res.redirect('http://other.url.com');

// GET /admin/users/

res.redirect('../login');

// => /admin/login

res.sendFile

Takes (optional) callback with error-first function signature

function fileSent(err){
  if(err){
    console.error(err);
    res.status(err.status).end();
  }
}

var options = { root: '/var/static/' };

res.sendFile('app.js', options , fileSent);

res.sendFile

app.get('/assets/protected/:filename' function(req,res){
  if(req.user && hasAccess(req.params.filename, req.user)){
    res.sendFile(req.params.filename, options, fileSent);
  }else{
    res.status(403).send('Not Authorized');
  }
});

// @return Boolean : true if user has access to requested file
function hasAccess(file, user){ /*...*/

res.download

res.download('/path/to/file.ext');

res.download('/path/to/file.ext', 'response.txt');

res.download('/path/to/file.ext', 'response.txt', fileSent);

res.render

http://expressjs.com/en/guide/using-template-engines.html

res.render('index');

res.render('userList', users);

res.render('user', {
  name: 'Michelle',
  role: 'Admin'
});

4.0 Router

// user-router.js
var router = require('express').Router();
module.exports = router;

router.get('/', allUsersHandler);
router.get(':id', getUserHandler);
router.post('/', createUserHandler);

// server.js
var app = require('express')();
var userRouter = require('./user-router');

app.use('/users/', userRouter);

// ...

start/restaurants-server-3.js

1. Move /restuarants/ routes to new external module
2. Mount router on /restaurants (paths work as before)

Hints:

1. Mount router on /foo, don't put /foo in router paths!!
2. Router module

    //fooRouter.js
    var Router = require('express').Router;
    var router = module.exports = Router();           
    router.get('/' /*...*/);
   

3. Using router module

    var router = require('./fooRouter')
    app.use('/foo', router);
   

Up Next: Middleware