Node.js :: Introduction — Part 2

Introduction to Node.js development. A brief talk about Node's API, frameworks & libs, use cases and prototyping.

2. PLAN Node.js Frameworks & Libs Demo application
3. NODE.JS is bad for: CPU heavy tasks Doing everything with Node
4. NODE.JS is good for: Prototyping REST / JSON APIs SPA Streaming data Real-time apps
5. MODULES Node Package Manager ~55k modules available
6. NPM npm install express npm install express -g npm install express --save npm install nodemon --save-dev
7. PACKAGE.JSON { "name": "application-name", "version": "0.0.1", "private": true, "scripts": { "start": "node app.js" }, "dependencies": { "express": "3.4.8", "jade": "*" }, "devDependencies: { } } npm publish <tarball> npm publish <folder>
8. HTTP SERVER var http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World!'); }).listen(3000); node server.js
9. WHAT'S INSIDE HTTP, HTTPS & TCP interfaces File System I/O Streams Child Process Cluster . . .
10. NETWORK INTERFACES HTTP/HTTPS/TCP // require a module var server = http || https || net; server.createServer([requestListener]).listen(port, [callback]);
11. FILE SYSTEM I/O var fs = require('fs'); fs.readFile(filename, [options], callback); fs.readFileSync(filename, [options]); fs.writeFile(filename, data, [options], callback); fs.writeFileSync(filename, data, [options]); fs.rmdir(path, callback); fs.unlink(path, callback); fs.readdir(path, callback);
12. STREAMS Readable (req, fs, stdout, stderr) Writable (res, fs, stdin) Duplex (TCP sockets, crypto) Transform (zlib, crypto)
13. STREAMS USE CASE http.createServer(function (req, res) { fs.readFile(__dirname + '/file.txt', function (err, data) { res.end(data); }); }); VS http.createServer(function (req, res) { var stream = fs.createReadStream(__dirname + '/file.txt'); stream.pipe(res); });
14. CHILD PROCESS var cp = require('child_process'); cp.spawn(command, [args], [options]); cp.exec(command, [options], callback); cp.execFile(file, [args], [options], [callback]); cp.fork(modulePath, [args], [options]); child.stdin // Writable stream child.stdout // Readable stream child.stderr // Readable stream // Sync, used with 'forked' process only child.send(message); child.on('message', callback);
15. CLUSTER var cluster = require('cluster'), http = require('http'), numCPUs = require('os').cpus().length; if (cluster.isMaster) { for (var i = 0; i < numCPUs; i++) { cluster.fork(); } } else { http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World!'); }).listen(3000); }
16. PROTOTYPING MEAN STACK MongoDB + Express + AngularJS + Node.js mean.io
17. EXPRESS Middleware system Router Templating (Jade, EJS) npm install -g express express appname
18. SETTING UP var express = require('express'), app = express(); app.set('port', process.env.PORT || 3000); app.set('view engine', 'jade'); app.set('views', __dirname + '/views'); app.use(express.bodyParser()); app.use(express.methodOverride()); app.use(app.router); app.use(express.static(path.join(__dirname, 'public'))); app.listen(app.get('port'));
19. MIDDLEWARES app.use(function (req, res, next) { // Do something... next(); // Call next middleware }); var middleware = function (req, res, next) { // Do something... next(); // Call next middleware };
20. ROUTES app.get('/', function (req, res) { res.render('index'); }); app.get('/user', middleware, function (req, res) { res.render('user'); // Render page for authorized users only });
21. ERROR HANDLING CUSTOM ERRORS var AuthError = function (msg) { Error.call(this); Error.captureStackTrace(this, arguments.callee); this.message = msg; this.name = 'AuthError'; }; AuthError.prototype.__proto__ = Error.prototype;
22. ERROR HANDLING ERROR MIDDLEWARE app.use(function (err, req, res, next) { if (err.name == 'AuthError') { res.send(401, {error: err.message}); } }); var middleware = function (req, res, next) { if (req.body.password != 'password') { return next(new AuthError('Unauthorized')); } next(); };
23. MONGODB Document-Oriented BSON data storage + Mongoose ODM var mongoose = require('mongoose'); mongoose.connect('mongodb://localhost/dbname');
24. MONGOOSE SCHEMAS var Schema = require('mongoose').Schema; var UserSchema = new Schema({ username: { type: String, unique: true, required: true }, comments: [{body: String, date: Date}], modified: { type: Date, default: Date.now }, role: String }); var User = mongoose.model('User', UserSchema);
25. CRUD var user = new User(data); user.save(function (err, user) {}); User.find(function (err, users) {}); User.find({role: 'Moderator'}, function (err, users) {}); User.findOne({username: 'user'}, function (err, user) {}); User.findById(id, function (err, user) { user.remove(function (err) {}); });
26. JSON/REST API app.post('/books', function (req, res, next) { var book = new Book(req.body); book.save(function (err, book) { if (err) return next(new Error('Server error')); res.send(200, {book: book}); }); }); app.get('/books/:id', function (req, res, next) { Book.findById(req.params.id, function (err, book) { if (err) return next(new Error('Server error')); if (!book) return res.send(404, {error: 'Not found'}); res.send(200, {book: book}); }); }); // ...
27. REAL-TIME SOCKET.IO var io = require('socket.io').listen(80); io.sockets.on('connection', function (socket) { socket.on('my event', function (data) {}); socket.emit('another event', data); });
28. DEMO TIME
29. WHAT ELSE? Forever Nodemon Node-Inspect Meteor JXcore CLI Front-end tools
30. LINKS nodejs.org/api github.com/substack/stream-handbook nodestreams.com howtonode.org nodeschool.io github.com/roman01la/RTVideo