Einführung in Node.js

Monday, March 11, 13

WER BIN ICH?

• Sebastian Springer

• https://github.com/sspringer82

• @basti_springer

• Teamlead @ Mayflower


https://github.com/sspringer82


THEMEN• Installation

• Node.js Shell

• Kernkomponenten

• NPM

• Events

• Streams

• HTTP

• Dateisystem

• Debugger

• Child_Process

• Cluster

• Tests

• Promises


https://github.com/sspringer82/nodeworkshop






INSTALLATION


HTTP://NODEJS.ORG/DOWNLOAD/


http://nodejs.org/download/




INSTALLATION


INSTALLATIONAuf welchen Systemen ist Node.js verfügbar?


INSTALLATION• Unix

• /usr/local/bin/node

• /usr/local/bin/npm

• /usr/local/lib/node_modules

• Windows

• C:\Program Files\nodejs\node.exe

• C:\Program Files\nodejs\npm

• C:\Program Files\nodejs\node_modules


INSTALLATION

$ wget http://nodejs.org/dist/v0.8.21/node-v0.8.21.tar.gz...$ tar xvzf node-v0.8.21.tar.gz...$ cd node-v0.8.21/$ ./configure --prefix=/opt/node/node-v0.8.21...$ make...$ sudo make install...

Suchpfad anpassen!


http://nodejs.org/dist/v0.8.21/node-v0.8.21.tar.gz

http://nodejs.org/dist/v0.8.21/node-v0.8.21.tar.gz

INSTALLATION

$ node --versionv0.8.22

Hat es funktioniert?


REPL


WHAT?


READ-EVAL-PRINT-LOOP

DIE NODE.JS SHELL


REPL

$ node> for (var i = 0; i < 3; i++) {... console.log(i);... }012undefined>


REPL

.break Bricht ein Multiline Statement ab

.clear Zurücksetzen + .break (CTRL + C)

.exit Beendet die aktuelle Shell (CTRL + D)

.help Liste der Befehle

.save Speichert die aktuelle Session

.load Lädt eine gespeicherte Session


KERNKOMPONENTEN


KERNKOMPONENTENStandard Library

Node Bindings

V8 libuv

Eventloop async I/O


KERNKOMPONENTEN



Node Bindings

V8 libuv

Eventloop async I/O


V8

• Schneller Zugriff auf Eigenschaften

• Dynamische Erstellung von Maschinencode

• Garbage Collection


V8 - FAST PROPERTY ACCESS


MASCHINENCODE


V8 - GARBAGE COLLECTION

• Programmausführung wird angehalten

• Es wird nur ein Teil des Object Heaps geprüft

• V8 kennt alle Objekte und Pointer im Speicher



Node Bindings

V8 libuv

Eventloop async I/O

libev + libeio IOCPMonday, March 11, 13

ASYNCHRONE OPERATIONEN

node.js Betriebssystem

Operation(z.B. lesen)


APPLIKATIONEN IN NODE.JS


APPLIKATIONEN IN NODE.JS

$ node helloWorld.js


X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XX X X


APPLIKATIONEN IN NODE.JSvar Star = function () { this.name = 'X', this.height = 20, this.step = 2;};

Star.prototype.top = function() { ...};

Star.prototype.print = function () { console.log(this.top().join('\n')); console.log(this.middle()); console.log(this.bottom().join('\n'));}

...

var star = new Star();star.print();


DAS MODULSYSTEM


DAS MODULSYSTEM

NPM

eigene Module

interne Module


INTERNE MODULEAssertion Testing

BufferChild_Process

ClusterCrypto

DebuggerDNS

DomainEvent

File System

HTTPHTTPS

NetOsPath

ProcessQueryString

ReadlineREPL

Stream

String DecoderTimersTLS/SSL

TTYUDPURL

UtilitiesVMZLIB


INTERNE MODULESTABILITÄTSINDEX

Index Name Beispiel

0 Deprecated util.pump

1 Experimental Domain, Cluster

2 Unstable Readline, Stream

3 Stable HTTP, Query String

4 API Frozen OS, Events

5 Locked Util, Assert


VERWENDUNG INTERNER MODULE

var os = require('os');

console.log('Betriebssystem: ' + os.type() + ' ' + os.platform() + ' ' + os.release() + ' ' + os.arch());

intModule.js


INTERNE MODULE - GLOBALS

• console

• process

• require

• Buffer

• set/clear-Timeout/Interval

• __filename + __dirname


EIGENE MODULE


EIGENE MODULE

• OH: “Wenn ich mir das Zeug, das in Node programmiert wurde, so ansehe, sieht das aus wie PHP3. Einfach von oben nach unten, alles in einer Datei”

• Liegen in einer separaten Datei

• Exportieren Klassen, Objekte oder Funktionen

• Können an anderer Stelle eingebunden werden


EIGENE MODULE

exports.email = function (email) { var regex = /^([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})$/, result = regex.exec(email);

if (result) { return true; }

return false;};

validator.js


VERWENDUNG EIGENER MODULE

var validator = require('./validator.js'), mail = ['[email protected]', 'Invalid Address'];

for (var i = 0; i < mail.length; i++) { if (validator.email(mail[i])) { console.log((i + 1) + '. Mailadresse ist gültig'); } else { console.log((i + 1) + '. Mailadresse ist ungültig'); }}

modules.js


EIGENE MODULE

$ node modules.js1. Mailadresse ist gültig2. Mailadresse ist ungültig


NPM

• Node Package Manager (von Isaac Schlueter)

• Bestandteil von Node.js seit 0.6.3

• https://github.com/isaacs/npm


https://github.com/isaacs/npm

https://github.com/isaacs/npm

NPM - REPO

• Hier kommen die Pakete für das npm-Kommando her

• https://npmjs.org/

• Aktuell über 24.000 Pakete

• https://registry.npmjs.org/-/all/


https://npmjs.org/

https://npmjs.org/

https://registry.npmjs.org/-/all/

https://registry.npmjs.org/-/all/

KOMMANDOS

• npm search <package>

• npm install <package>

• npm list

• npm update

• npm remove


NPM SEARCH

$ npm se mysqlnpm http GET https://registry.npmjs.org/-/all/since?stale=update_aft...npm http 200 https://registry.npmjs.org/-/all/since?stale=update_aft...NAME DESCRIPTION AUTHOR DATE KEYWORDS...Accessor_M... A MySQL database wrapper... =bu 2012-1... mysql ac...any-db Database-agnostic connec... =grncdr 2013-0... mysql po...autodafe mvc framework for node w... =jifeon 2012-1... mvc fram...backbone-m... A sync module for Backbo... =ccowan 2012-1...caminte ORM for every database: ... =biggor 2013-0... caminte ...connect-my... a MySQL session store fo... =nathan 2012-0... connect-my... A MySQL session store fo... =daniel 2011-0...cormo ORM framework for Node.j... =croqui 2013-0... orm mong...


https://registry.npmjs.org/-/all/since?stale=update_after&startkey=1359798720163




NPM INSTALL$ npm in mysqlnpm http GET https://registry.npmjs.org/mysqlnpm http 200 https://registry.npmjs.org/mysqlnpm http GET https://registry.npmjs.org/bignumber.js/1.0.1npm http GET https://registry.npmjs.org/require-all/0.0.3npm http 200 https://registry.npmjs.org/require-all/0.0.3npm http GET https://registry.npmjs.org/require-all/-/requi...npm http 200 https://registry.npmjs.org/bignumber.js/1.0.1npm http GET https://registry.npmjs.org/bignumber.js/-/bign...npm http 200 https://registry.npmjs.org/require-all/-/requi...npm http 200 https://registry.npmjs.org/bignumber.js/-/[email protected] node_modules/mysql!"" [email protected]#"" [email protected]


https://registry.npmjs.org/mysql




https://registry.npmjs.org/bignumber.js/1.0.1


https://registry.npmjs.org/require-all/0.0.3




https://registry.npmjs.org/require-all/-/require-all-0.0.3.tgz




https://registry.npmjs.org/bignumber.js/-/bignumber.js-1.0.1.tgz






NPM LIST

$ npm ls/srv/node#"$ [email protected] !"" [email protected] #"" [email protected]


mailto:[email protected]






NPM UPDATE

$ npm upnpm http GET https://registry.npmjs.org/mysqlnpm http 304 https://registry.npmjs.org/mysqlnpm http GET https://registry.npmjs.org/require-all/0.0.3npm http GET https://registry.npmjs.org/bignumber.js/1.0.1npm http 304 https://registry.npmjs.org/bignumber.js/1.0.1npm http 304 https://registry.npmjs.org/require-all/0.0.3














NPM REMOVE

$ npm rm mysql$ npm ls/srv/node#"" (empty)


EIGENE NPM-PAKETE


{ "author": { "name": "Felix Geisendörfer", "email": "[email protected]", "url": "http://debuggable.com/" }, "name": "mysql", "description": "A node.js driver for mysql...", "version": "2.0.0-alpha7", "repository": { "url": "" }, "main": "./index", "scripts": { "test": "make test" }, "engines": { "node": "*" }, "dependencies": { "require-all": "0.0.3", "bignumber.js": "1.0.1" }, "devDependencies": { "utest": "0.0.6", "urun": "0.0.6", "underscore": "1.3.1" }, "optionalDependencies": {}, "readme": "# node-mysql\n\n[![Build Status]...", "readmeFilename": "Readme.md", "_id": "[email protected]", "_from": "mysql"}


http://debuggable.com/

http://debuggable.com/

EIGENE NPM-PAKETE

• npm adduser

• Username, Passwort, E-Mail

• npm publish <folder>|<tarball>


https://github.com/joyent/node/wiki/Modules






EVENTS


EVENTSEvent Emitter Subscriber

on(‘message’, function (e) {...

emit(‘message’, ‘data’)


EVENTS

• Basis vieler Module

• Grundlage für eventgetriebene Architektur

• Ereignisse zum Informationsaustausch

• emit(event, [arg1], [arg2], [...]) - Publish

• on(event, listener) - Subscribe


EVENTEMITTER

var EventEmitter = require('events').EventEmitter, util = require('util');

var MessageBus = function () {};

util.inherits(MessageBus, EventEmitter);

exports.MessageBus = MessageBus;

messageBus.js


EVENTEMITTER

var MessageBus = require('./messageBus.js').MessageBus;

var mb = new MessageBus();

mb.on('message', function (data) { console.log('Received new message: ' + data)});

mb.emit('message', 'Hello World');

events.js


EVENTEMITTER

$ node events.js Received new message: Hello World


EVENTS

• Wo kommen Events zum Einsatz?

• child_process, cluster, dgram, domain, fs, http, net, readline, repl, stream, tls


STREAMS


STREAMS

• Repräsentieren Datenströme in Node.js

• Abstraktes Interface

• Les- und/oder schreibbare Streams


READABLE STREAM

• Events

• data

• end

• error

• close

• Methoden

• pause

• resume

• destroy

• pipe

• setEncoding


WRITABLE STREAM

• Events

• drain

• error

• close

• pipe

• Methoden

• write

• end

• destroy

• destroySoon


STREAMS

• Wo kommen Streams zum Einsatz?

• fs, http, net repl, tls, zlib


STREAMS IN DER PRAXIS?


http://www.google.com




DER KLASSIKER


HTTP-SERVER

var http = require('http');

http.createServer(function (req, res) { res.end('Hello World');}).listen(8080);

http.js


HTTP-SERVER$ node http.js


require('http').createServer(function (req, res) { var body, status, reqData;

if (req.headers['user-agent'].search(/MSIE/) != -1) { body = 'wrong Browser'; status = 403; } else { body = 'Hello Client'; status = 200; }

req.on('data', function (data) { reqData += data; }).on('end', function () { if (reqData) console.log(reqData); });

res.writeHead(status, { 'Content-Length': body.length, 'Content-Type': 'text/plain' }); res.write(body); res.end();}).listen(8080);


HTTP-SERVER

• http.ServerRequest: Readable Stream

• http.ServerResponse: Writable Stream


HTTP-CLIENT?


DATEISYSTEM


DATEISYSTEM-FUNKTIONEN

• exists

• readFile

• writeFile

• appendFile

• watchFile

• rename

• unlink

• chmod

• chown

• ...


SYNC VS. ASYNC


DATEI LESEN

var fs = require('fs') filename = process.argv[2] || 'input.txt';

fs.readFile(filename, 'utf8', function (err, data) { if (err) { console.error("File cound not be opened"); return false; } console.log(data); return true;});


DATEI LESEN

$ node readFile.jsHello World!


DATEI LESEN

$ node readFile.jsHello World!

$ node readFile.js nonexistant.txtFile cound not be opened


FILE EXISTS$ ls -l input.txt -rw-r--r-- 1 sspringer staff 12 Mar 7 09:06 input.txt



var fs = require('fs'), filename = process.argv[2] || 'input.txt';

fs.exists(filename, function (exists) { if (exists) { console.log('File exists'); return true; } console.error('There is no such file'); return false;});



var fs = require('fs'), filename = process.argv[2] || 'input.txt';

fs.exists(filename, function (exists) { if (exists) { console.log('File exists'); return true; } console.error('There is no such file'); return false;});

$ node fileExists.jsFile exists


APPEND FILE$ cat input.txtHello World!



var fs = require('fs'), data = process.argv[2] || 'Hello my World';

fs.appendFile('input.txt', data, function (err) { if (err) { console.error('Could not write into file'); return false; } console.log('Success!'); return true;});



var fs = require('fs'), data = process.argv[2] || 'Hello my World';

fs.appendFile('input.txt', data, function (err) { if (err) { console.error('Could not write into file'); return false; } console.log('Success!'); return true;});

$ node appendFile.js 'Hallo München!'Success!$ cat input.txt Hello World!Hallo München!


WATCH FILEvar fs = require('fs');

fs.watch('input.txt', function (e) { if (e === 'change') { console.log('File changed'); } else if (e === 'rename') { console.log('File renamed'); }});


WATCH FILE

$ node watchFile.js

var fs = require('fs');



WATCH FILE

$ echo 'Hello World!' > input.txt

$ node watchFile.js




WATCH FILE

$ echo 'Hello World!' > input.txt

$ node watchFile.js

$ node watchFile.js File changed




DEBUGGER


BEISPIELCODEvar myObj = {a: 1, b: 2};

console.log(myObj);

myObj.a = 'Hello';

console.log(myObj);

for (var i = 0; i < 10; i++) { var helper = function () { // do something console.log(i) }; helper();}


DEBUGGER

$ node debug debugger.js< debugger listening on port 5858connecting... okbreak in debugger.js:1 1 var myObj = {a: 1, b: 2}; 2 3 console.log(myObj);debug>


DEBUGGER - STEP

Kommando Bedeutung Beschreibung

n next Fortsetzen

c cont Step over

s step Step in

o out Step out


DEBUGGER - WATCH

• watch(expression)

• unwatch(expression)

• watchers


DEBUGGER - WATCH

debug> watch('myObj')debug> nbreak in debugger.js:3Watchers: 0: myObj = {"b":2,"a":1}

1 var myObj = {a: 1, b: 2}; 2 3 console.log(myObj); 4 5 myObj.a = 'Hello';debug>


DEBUGGER - REPLdebug> replPress Ctrl + C to leave debug repl> myObj{ b: 2, a: 1 }> myObj.b = 14;14> myObj{ b: 14, a: 1 }debug> n< { a: 1, b: 14 }break in debugger.js:5Watchers: 0: myObj = {"b":14,"a":1}

3 console.log(myObj); 4 5 myObj.a = 'Hello'; 6 7 console.log(myObj);debug>


DEBUGGER

• Kommandozeilen Debugger

• Kommandos

• Debugging einer Applikation


CHILD_PROCESS


CHILD_PROCESS

• spawn - Kommandoausführung

• exec - Kommandoausführung in Puffer

• execFile - Dateiausführung in Puffer

• fork - Node Prozess


ETWAS RECHENINTENSIVES

module.exports = function () { var i, n = 1, results = 1; primeLoop: while (results < 300000) { n += 1; for (i = 2; i <= Math.sqrt(n); i += 1) { if (n % i === 0) { continue primeLoop; } } results += 1; } return n;};

cp1.js


ETWAS BLOCKIERENDESpotenziell


http.createFakeServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n');}).listen(1337, '127.0.0.1');

console.log('Server running at http://127.0.0.1:1337/');

cp2.js


http://127.0.0.1:1337/

http://127.0.0.1:1337/

ETWAS BLOCKIERENDES

var http = require('http'), prime = require('./cp1.js');

http.createServer(function (req, res) { console.time('Request answered in'); console.log('incoming Request');

var number = prime();

res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n');

console.timeEnd('Request answered in');}).listen(1337, '127.0.0.1');


cp3.js


http://127.0.0.1:1337/

http://127.0.0.1:1337/

ETWAS BLOCKIERENDES

$ node cp3.js Server running at http://127.0.0.1:1337/incoming RequestRequest answered in: 4713msincoming RequestRequest answered in: 4703ms


http://127.0.0.1:1337

http://127.0.0.1:1337

DIE LÖSUNG: WIR FORKEN


CHILD_PROCESS


http.createServer(function (req, res) { console.time('Request answered in'); console.log('incoming Request');

require('child_process').fork('./primeHelper.js') .on('message', function (data) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('The 300000st prime number is: ' + data.prime);

console.timeEnd('Request answered in'); });}).listen(1337, '127.0.0.1');


cp4.js


http://127.0.0.1:1337/

http://127.0.0.1:1337/

CHILD_PROCESS

primeHelper.js

var prime = require('./cp1.js')();

process.send({'prime': prime});


CHILD_PROCESS

$ node cp4.js Server running at http://127.0.0.1:1337/incoming Requestincoming RequestRequest answered in: 4242msRequest answered in: 4913ms


http://127.0.0.1:1337

http://127.0.0.1:1337

CHILD_PROCESS

• Threadmodell von Node.js

• Möglichkeiten von child_process - fork, spawn, exec

• Kommunikation zwischen Eltern- und Kindprozess


CLUSTER


CLUSTER

• Loadbalancing über CPU

• Funktioniert mit allen Instanzen von “net.Server”

• ...auch mit http



for (var i = 0; i < 100; i++) { http.get('http://localhost:8000', function (res) { console.log(res); });}

clusterClient.js


http://localhost:8000/

http://localhost:8000/

CLUSTER

• node cluster.js

• node clusterClient.js


CLUSTERWorker 38128 respondsWorker 38128 respondsWorker 38127 respondsWorker 38127 respondsWorker 38128 respondsWorker 38127 respondsWorker 38128 respondsWorker 38127 respondsWorker 38127 respondsWorker 38127 respondsWorker 38128 respondsWorker 38127 respondsWorker 38128 respondsWorker 38127 respondsWorker 38128 respondsWorker 38127 respondsWorker 38127 respondsWorker 38128 respondsWorker 38127 responds


TESTING


UNITTESTS

• Absicherung von Applikationen

• Tests auf Funktionsebene

• Node.js testet eigene Module ebenfalls

• Assert-Modul

• node-v0.8.22/test/simple


ASSERTION TESTING


ASSERTION TESTING

• var assert = require(‘assert’)

• Assertion-Methoden

• Sehr wenig Rückmeldung

• Nur ein Failure


ASSERTION TESTINGfail Wirft einen

AssertionErrorok(value, [message]) Pass, wenn der Wert

true istequal(actual, expected, [message]) Vergleich mit ==

deepEqual(actual, expected, [message]) Vergleich über Strukturen

strictEqual(actual, expected, [message]) Vergleich mit ===

throws(block, [error], [message]) Pass, wenn eine Exception geworfen wird

NOT! - notEqual(...)Monday, March 11, 13

ASSERTION TESTING

var assert = require('assert'), actual = 'Hello World', expected = 'Hello World';

assert.equal(actual, expected, 'Strings are not Equal');

assert.notEqual(actual, expected, 'Strings are Equal');

assert.fail('FAIL!', 'PASS!', 'This fails!');

assert.js


ASSERTION TESTING

$ node assert.js

assert.js:102 throw new assert.AssertionError({ ^AssertionError: Strings are Equal at Object.<anonymous> (/tmp/node/assert.js:7:8) at Module._compile (module.js:449:26) at Object.Module._extensions..js (module.js:467:10) at Module.load (module.js:356:32) at Function.Module._load (module.js:312:12) at Module.runMain (module.js:492:10) at process.startup.processNextTick.process._tickCallback (node.js:244:9)


NODEUNIT


NODEUNIT

• npm install -g nodeunit

• Die gleichen Assertion-Methoden wie im Assert-Modul

• More verbose

• Mehrere Failures


module.exports = { setUp: function (callback) { console.log('setUp'); callback(); }, tearDown: function (callback) { console.log('tearDown'); callback(); }, firstExample: function (test) { console.log('firstExample') test.equal('Hello', 'Hello', 'Strings are not Equal'); test.done(); }, exampleGroup: { secondExample: function (test) { test.notEqual('Hello', 'Hello', 'Strings are Equal'); test.done(); }, thirdExample: function (test) { test.fail('FAIL!', 'PASS!', 'This fails!'); test.done(); } }}


$ nodeunit nodeunit.js

nodeunit.jssetUpfirstExampletearDown✔ firstExamplesetUptearDown✖ exampleGroup - secondExample

Assertion Message: Strings are EqualAssertionError: 'Hello World' != 'Hello World' at Object.assertWrapper [as notEqual] (...

setUptearDown✖ exampleGroup - thirdExample

AssertionError: 'FAIL!' undefined 'PASS!' at Object.assertWrapper [as fail] (...

FAILURES: 2/3 assertions failed (5ms)


PROMISES


PROMISES

• Ergebnis eines asynchronen Funktionsaufrufs

• Rückgabewert oder Exception

• Promise statt Blocking

• CommonJS Proposal

• Bis 0.2 Bestandteil von Node


PYRAMID OF DOOM

step1(function (value1) { step2(value1, function (value2) { step3(value2, function (value3) { step3(value3, function (value4) { // do something }); }); });});


PROMISES

Q.fcall(step1) .then(step2) .then(step3) .then(step4) .then(function (value4) { // do something with value 4 }, function (error) { // Handle any error from step1 through step4 }) .end();


PROMISE-LIBRARIES

• https://github.com/kriskowal/q

• https://github.com/kriszyp/node-promise (lightweight)

• https://github.com/kriszyp/promised-io (complete API)

• ...


https://github.com/kriskowal/q

https://github.com/kriskowal/q

https://github.com/kriszyp/node-promise

https://github.com/kriszyp/node-promise

https://github.com/kriszyp/promised-io

https://github.com/kriszyp/promised-io

OHNE PROMISESvar fs = require('fs');

fs.exists('input.txt', function (exists) { fs.stat('input.txt', function (err, stats) { fs.open('input.txt', 'r+', function (err, fd) { fs.read(fd, new Buffer(stats.size), 0, stats.size, null, function (err, read, buff) { if (err) throw err; console.log(buff.toString()); fs.close(fd, function () { console.log('File Handle closed'); }); } ) }); });});


MIT PROMISES


AUSFÜHRUNG

$ node promises2.js Hello World

File Handle closed


JETZT HABT IHR’S GESCHAFFT


FRAGEN?


KONTAKT

Sebastian [email protected]

Mayflower GmbHMannhardtstr. 680538 MünchenDeutschland

@basti_springer







OHNE PROMISES


PROMISES


Einführung in Node.js

Technology

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