Node.js - As a networking tool

Node.js As a networking tool 28.12.2010

About Contributor Co-founder Felix Geisendörfer node.js driver node-formidable

Node's goal is to provide an easy way to build scalable network programs.

Node.js • Created by Ryan Dahl • Google’s V8 JavaScript engine (no DOM) • Module system, I/O bindings, Common Protocols

N et w or k Hello World Ed it io n $ cat hello.js var net = require('net'); net.createServer(function(socket) { socket.write('hello worldn'); socket.end(); }).listen(0x27C3); $ node hello.js & [1] 3591 $ nc localhost 10179 hello world

V8 (Chrome) SpiderMonkey (Firefox) JavaScriptCore (Safari) #2 - JS Engine Wars Chakra (IE9) Carakan (Opera)

Blocking I/O db.query('SELECT A'); console.log('query A done'); db.query('SELECT B'); console.log('query B done'); Time = SUM(A, B)

Non-Blocking I/O db.query('SELECT A', function(result) { console.log('query A done'); }); db.query('SELECT B', function(result) { console.log('query B done'); }); Time = MAX(A, B)

libev • An inﬁnite loop (event loop) • Polls the OS for events (select, epoll, kqueue, ...) • Allows you to register watchers / callbacks for the events you care about

Buffers • Raw C memory allocation • Similar to an array of integers • Can be converted to and from JS strings

Buffers buffer.write('Hello Buffer'); buffer.toString('utf-8'); buffer[0] = 23; buffer.slice(10, 20);

Reverse Hello World $ cat reverse_hello.js var net = require('net'); net.createServer(function(socket) { socket.on('data', function(buffer) { console.log(buffer); }); }).listen(0x27C3); $ node reverse_hello.js & [1] 3523 $ echo "hello world" | nc localhost 10179 <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64 0a>

“Streams are to time as arrays are to space.” -- Jed Schmidt @ JSConf.eu

Streams stream.write(new Buffer([0x27, 0xC3]); stream.pause(); stream.resume(); stream.destroy();

Streams stream .on('drain', function() {}) .on('data', function(buffer) {}) .on('end', function() {});

Streams $ cat echo.js var net = require('net'); net.createServer(function(socket) { socket.pipe(socket); }).listen(0x27C3); $ node echo.js & [1] 6207 $ nc 127.0.0.1 10179 Hi, how are you? Hi, how are you?

pcap module Snifﬁng data with node.js

pcap module • Node.js bindings for libpcap • Simple install: `npm install pcap` • “Scriptable tcpdump”

pcap module $ cat pcap.js var util = require('util'); var pcap = require('pcap'); var filter = 'tcp port '+0x27C3; var session = pcap.createSession('lo0', filter); session.on('packet', function(packet) { packet = pcap.decode.packet(packet); console.log(pcap.print.packet(packet)); if (packet.link.ip.tcp.data) { util.print(packet.link.ip.tcp.data.toString()); } });

pcap module $ node hello.js > /dev/null & [1] 3592 $ sudo node pcap.js & [2] 3593 $ nc 127.0.0.1 10179 > /dev/null loopback 127.0.0.1:54078 -> 127.0.0.1:10179 TCP len 64 [syn] loopback 127.0.0.1:10179 -> 127.0.0.1:54078 TCP len 64 [ack,syn] loopback 127.0.0.1:54078 -> 127.0.0.1:10179 TCP len 52 [ack] loopback 127.0.0.1:10179 -> 127.0.0.1:54078 TCP len 64 [ack,psh] hello world loopback 127.0.0.1:54078 -> 127.0.0.1:10179 TCP len 52 [ack]

Recap • Binary data handling (Buffers) • I/O abstraction (Streams) • Packet snifﬁng (node-pcap)

Node can also do • HTTP • Child processes • Unix domain sockets • DNS • UDP • Crypto • ...

Speed var http = require(’http’) var b = new Buffer(1024*1024); http.createServer(function (req, res) { res.writeHead(200); res.end(b); }).listen(8000); by Ryan Dahl

Speed 100 concurrent clients 1 megabyte response node 822 req/sec nginx 708 thin 85 mongrel 4 (bigger is better) by Ryan Dahl

Speed • NGINX peaked at 4mb of memory • Node peaked at 60mb • Very special circumstances by Ryan Dahl

Danger, Will Robinson Node makes it trivial to manage thousands of connections on multiple protocol levels.

File uploading & processing as a service for other web applications.

Questions? ✎ @felixge / felix@debuggable.com

Addons • Add bindings to your favorite C/C++ libraries • Can be written as a mix of C++ / JavaScript

Addons #include <v8.h> #include <node.h> #include <unistd.h> using namespace v8; static Handle<Value> Fork(const Arguments& args) { HandleScope scope; pid_t pid = fork(); if (pid < 0) { return ThrowException(Exception::Error(String::New("fork: could not fork, pid < 0. see man fork"))); } if (pid == 0) { ev_default_fork(); } return scope.Close(Number::New(pid)); } extern "C" void init (Handle<Object> target) { HandleScope scope; NODE_SET_METHOD(target, "fork", Fork); }

Node.js - As a networking tool

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