Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

Node.js is a platform built on Chrome's JavaScript runtime [...]

[...] easily building fast, scalable network applications.

Node.js uses an event-driven, non-blocking I/O model [...]

Everything happens in Parellel execpt for your code.

              var fs  = require('fs');
              var sys = require('sys');

              fs.readFile('treasure-chamber-report.txt', function readFile(report) {
                sys.puts("oh, look at all my money: "+report);
              });

              fs.writeFile('letter-to-princess.txt', '...', function writeFile() {
                sys.puts("can't wait to hear back from her!");
              });
            

                $ ssh YOU@nodejs.4kclass.com
              

                $ sftp YOU@nodejs.4kclass.com
              

~/nodejs

                ~/nodejs/js101
                ~/nodejs/exercises/drupal
                ~/nodejs/exercises/server
              

              var http = require('http');
              http.createServer(function hello(request, response) {
                res.writeHead(200, {'Content-Type': 'text/plain'});
                res.end('Hello World\n');
              }).listen(1337);
              console.log('Server running at http://127.0.0.1:1337/');
            

              $ cd ~/nodejs/exercies
              $ express myserver
              $ cd myserver
              $ npm install
            

                  $ cp ~/config.js ~/nodejs/exercises/myserver/config.js
                

-  , path = require('path');
+  , path = require('path')
+  , config = require('./config');
            

-  app.set('port', process.env.PORT || 3000);
+  app.set('port', config.port);
            

              app.post('/ping', function postPing(request, response){
                console.log(request.body);      // your JSON
                response.send(request.body);    // echo the result back
              });
            

              $data = array('title' => $node->title);
              $data = drupal_json_encode($data);
              $uri = variable_get('ping_nodejs_uri','http://localhost:3000/ping');

              $options = array();
              $options['headers'] = array('Content-Type' => 'application/json');
              $options['method'] = 'POST';
              $options['data'] = $data;
              $response = drupal_http_request($uri, $options);

              if ($response->code != 200) {
                drupal_set_message("Got an error: " . $response->error, 'error');
              }
              else {
                drupal_set_message('Successfully contacted node server. Response was: ' . $response->data);
              }
            

              console.log("I'm going to read a file synchronously.");

              syncContents = fs.readFileSync(__filename);

              console.log("I'm done reading the file synchronously.");
              console.log('I read ' + syncContents.length + ' characters.');
              console.log("Now I'm ready to do the next thing.");
            

              console.log("I'm going to read a file asynchronously.");
              fs.readFile(__filename, function readFile(err, data) {
                asyncContents = data;
                console.log("I'm done reading the file asynchronously.");
                console.log('I read ' + asyncContents.length + ' characters.');
              });
              console.log("Now I'm ready to do the next thing.");
            

              var start = Date.now();

              setTimeout(function timeout1() {
                console.log('We started execution ' + (Date.now() - start) + 'ms ago.');

                for (var x = 0; x < 3999999999; x++) {}

                console.log('Done with timeout1().');
              }, 1000);

              setTimeout(function timeout2() {
                console.log('We started execution ' + (Date.now() - start) + 'ms ago.');
                console.log('Done with timeout2().');
              }, 2000);
            

              ~/nodejs/require/modules
            

console.log('this is a');

console.log(' this is b');

              // Note the relative paths, leaving this off for libraries you
              // define is a common mistake.
              require('./module_a');
              require('./module_b')
            

              {
                "author": "Four Kitchens  (http://fourkitchens.com/)",
                "name": "npmExample",
                "description": "An example from the world famous Four Kitchens Node.js training.",
                "version": "0.0.1",
                "homepage": "http://fourkitchens.com",
                "repository": {
                  "type": "git",
                  "url": "git://github.com/fourkitchens/train-node.git"
                },
                "engines": {
                  "node": "~0.8.8"
                },
                "dependencies": {},
                "devDependencies": {},
                "optionalDependencies": {}
              }
            

NPM

• Node's Personal Manservant
• Collection of over 16k community built libraries
• Handles installation and dependencies
• Everything from GPIO libraries to a few CMSs

              $ mkdir ~/nodejs/require/colorsExample
              $ cd ~/nodejs/require/colorsExample
              $ npm init
              $ npm install colors
            

              npm install --save colors
            

              // colorsExample.js
              var colors = require('colors');

              console.log('hello'.green); // outputs green text
            

              console.log('i like cake and pies'.underline.red) // outputs red underlined text
              console.log('inverse the color'.inverse); // inverses the color
              console.log('OMG Rainbows!'.rainbow); // rainbow (ignores spaces)
            

              var request = require('superagent');

              /**
               * Get Nodes function
               *
               */
              module.exports  = function nodes (url, fn) {
                request.get(url)
                  .end(function gotNodes(res) {
                    if (res.body) {
                      return fn(null, res.body);
                    }
                  });
              };
            

-  app.set('view engine', 'jade');
+  app.set('view engine', 'html');
+  app.engine('html', require('hbs').__express);
            

              app.get('/nodes', function getNodes(req, res, next) {
                nodes('http://instructor.nodejs.4kclass.com/exercises/drupal/rest/node.json', function renderNodes(err, nodes) {
                  console.log(nodes);
                  if (err) return next( err);
                  res.render('nodes', { results: nodes });
                });
              });
            

Socket.IO aims to make realtime apps possible in every browser and mobile device, blurring the differences between the different transport mechanisms. It's care-free realtime 100% in JavaScript.

              var io = require('socket.io').listen(80);

              io.sockets.on('connection', function onConnection(socket) {
                socket.emit('news', { hello: 'world' });
                socket.on('my other event', function onMyOtherEvent(data) {
                  console.log(data);
                });
              });
            

              var socket = io.connect('http://localhost');
              socket.on('news', function onNews(data) {
                console.log(data);
                socket.emit('my other event', { my: 'data' });
              });
            

                {
                  title: 'Story title',
                  description: 'Story body text',
                  link: 'URL to the story'
                }
              

                {
                  name: 'Message Author',
                  message: 'Message body text!',
                  time: new Date()
                }
              

                {
                  picture: 'URL to the image',
                  link: 'URL to where the image should be linked to'
                }
              

              ~/nodejs/exercises/server/app.js
            

              // Keep a counter.
              var count = 0;
              /**
               * Notifies the client of new stories.
               */
              setInterval(function newStories() {
                // Increment the counter.
                count++;

                // Create some story content to send to the client.
                var newStories = [
                  {
                    title: 'New story ' + count,
                    description: 'New story text for ' + count,
                    link: 'http://fourkitchens.com'
                  }
                ];

                // Broadcast the new stories to all clients.
                io.sockets.emit('newStories', newStories);
              }, config.pollInterval || 10000);
            

              /**
               * Notifies the client of new stories.
               */
              setInterval(function newStories() {
                nodes('http://instructor.nodejs.4kclass.com/rest/node.json', function gotNodes(err, nodes) {
                  if (err) { return next(err); }

                  var newStories = [];

                  nodes.forEach(function eachNode(node) {
                    newStories.push({
                      title: node.title,
                      description: node.title + ' (nid: ' + node.nid + ')',
                      link: 'http://instructor.nodejs.4kclass.com/node/' + node.nid
                    });
                  });

                  io.sockets.emit('newStories', newStories);
                });
              });
            

              app.get('/messages', function getMessages(req, res) {
                var messages = [
                  {
                    name: 'Training bot',
                    message: 'Welcome to node.js training!',
                    time: new Date()
                  }
                ];

                res.json(messages);
              });
            

              app.post('/message', function postMessage(req, res) {
                res.writeHead(204);
                res.end();

                var newMessages = [req.body];
                io.sockets.emit('newMessages', newMessages);
              });
            

              var http = require('http');
              http.createServer(function hello(request, response) {
                res.writeHead(200, {'Content-Type': 'text/plain'});
                res.end('Hello World\n');
              }).listen(1337);
              console.log('Server running at http://127.0.0.1:1337/');
            

              file.on('data', function(chunk){
                console.log(chunk.toString());
              });
            

            fs.readFile('index.html', function(err, data) {
              if (err) throw err;
              console.log(data.toString());
            });
            

              fs.readFile('index.html', function (err, data) {
                if (err) {
                  res.statusCode = 500;
                  res.end(String(err));
                }
                else res.end(data);
              });
            

              var file = fs.createReadStream('index.html');
              file.pipe(res);
            

              var mysql = require('mysql');
              var conn = mysql.createConnection({
                host: 'localhost',
                user: 'you',
                password: 'unsafe'
              });
              conn.connect();

              conn.query('SELECT "Hello world" AS message', function selectResult(err, rows, fields) {
                if (err) {
                  throw err;
                }

                console.log(rows[0].message);
              });
              conn.end();
            

              db.test.insert({
                title: 'test',
                message: 'Hello world'
              });
              db.test.find({ title: 'test' }).pretty();
              db.test.update(
                { title: 'test' },
                { $set: { message: 'Yo dawg' } }
              );
              db.test.find({ title: 'test' }).pretty();
            

              db.test.update(
                { title: 'test'},
                { $set: {
                  speaker: {
                    name: 'Elliott Foster',
                    occupation: 'Hipster Technologist',
                    interests: [
                      'JavaScript',
                      'beer',
                      'bicycles'
                    ]
                  }
                } }
              );
              db.test.find({ 'speaker.name': 'Elliott Foster' }).pretty();
            

              var mongode = require('mongode');
              var test = mongode.connect('mongo://127.0.0.1/test');
              var collection = test.collection('test');
              var doc = { title: 'test2', message: 'node and mongo, yay!' };
              collection.insert(doc, {safe:true}, function insertResult(err, objects) {
                if (err) {
                  console.error(err.message);
                  process.exit(1);
                }
                collection.findOne({ title: 'test2' }, function findOneResult(err, document) {
                  if (err) {
                    console.error(err.message);
                    process.exit(1);
                  }
                  console.log(document.message);
                  process.exit(0);
                });
              });
            

              // basic imports
              var events = require('events');
              var util = require('util');

              function Poll(feed) { this.feed = feed; };
              util.inherits(Poll, events.EventEmitter);

              Poll.prototype.getStories = function(callback) {
                var self = this;

                /**
                 * Assume fetchStories grabs an array of content and
                 * executes this callback on completion.
                 */
                fetchStories(self.feed, function gotStories(err, newStories) {
                  if (!err && newStories.length) {
                    self.emit('fed', null, newStories);
                  }
                });
              };
              exports.Poll = Poll;
            

              var awesomeCompany = {
                name: 'Four Kitchens',
                location: 'Austin, TX'
              };

              console.log(awesomeCompany.name + ' is awesome!');
            

              var awesomeCompany = {
                name: 'Four Kitchens',
                location: 'Austin, TX',
                knowsNode: function() {
                  return true;
                }
              };

              if (awesomeCompany.knowsNode()) {
                console.log(awesomeCompany.name + ' knows node!');
              }