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Got milk?

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No content

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milk = dear_son.please_buy_a_milk();

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milk = dear_son.please_buy_a_milk();

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milk = dear_son.please_buy_a_milk(); dear_son.thank_you(); milk.drink();

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milk = dear_son.please_buy_a_milk(); dear_son.thank_you(); milk.drink(); Blocking operations

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milk = dear_son.please_buy_a_milk();

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milk = dear_son.please_buy_a_milk(); do_cleanup(); do_something_else();

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milk = dear_son.please_buy_a_milk(); do_cleanup(); do_something_else(); /* ? dear_son.here_is_your_milk(); */ Non-Blocking operations

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Event-Loop

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milk = dear_son.please_buy_a_milk(); /* Event loop starts - while(…) */ if( dear_son.milk_ready() ) break; do_some_cleanup(); /* Event loop ends */ Event-Loop

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In terms of: 1. OS ( process, threads scheduling) 2. Application ( event-loops, overlapped system calls, callbacks )

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OS can handle it. So why should I know about event-loops and other sh!t?!

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That’s why

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Introducing Node.Js! Event-driven I/O server-side JavaScript framework based on V8

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Why Javascript? 1. It’s awesome 2. It’s simple 3. It’s popular 4. V8 is really fast 5. Built-in support for callbacks, lambdas, closures and other magic

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setTimeout(function() { console.log('Hello, '); }, 1000); console.log(' World!'); Dummy example #1

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Dummy example #2 var http = require(‘http’); http.createServer(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 port 1337');

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Web-Server | CGI | php, perl, python, etc.

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Node.Js (all-in-one: web-server, caching, parsing, templating, data-storing, doing-a-sandwich)

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Features 1. Clustering 2. Packages: web-frameworks, DB, graphics, BNF parsers, unit- testing, … + package manager 3. Cloud 9 IDE (runs in browser)

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Problems Asynchronous logic hell!

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Problems Asynchronous logic hell! 1. Using helper modules (deferred, async, node-fibers) 2. Program is Finite State Machine

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The main problem Node.Js is very young, so be careful! Use it just-for-fun!

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Resources 1. “UNIX internals” by U.Vahalia 2. “Thinking Asynchronous in C++” by author of boost::asio http://blog.think-async.com/ 3. Online npm repository http://search.npm.js 4. Cloud 9 IDE http://c9.io

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Have a nice milk! Speaker: Taktarov A. Drawings: Taktarov E. molefrog[at]gmail.com