NodeJS overview
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NodeJS is a server-side JavaScript platform that uses Google's V8 JavaScript engine and a non-blocking I/O model. It allows for 100% CPU usage on a single thread by using an event-driven, non-blocking I/O model. NodeJS is well-suited for real-time applications and can handle more requests per second than traditional threaded servers like Apache while using less memory. It allows for common codebases and testing across front-end and back-end JavaScript applications using many popular frameworks. Comet applications also benefit from NodeJS's non-blocking I/O model which allows for long-held connections without dedicating a thread per connection.
NodeJS overview
- 1. NodeJS
- 2. Milestones ● Server-side Javascript based on Google V8 ● Non-blocking Input/Output event model ● 100% CPU using: one process - one thread - one core
- 3. Google V8 ● V8 JavaScript VM is used in Google Chrome ● No JIT, all JavaScript is compiled to assembler ● Hidden classes optimization from Self (V8 does not dynamically lookup access properties, instead it uses hidden classes that are created behind the scene) ● Improved garbage collector
- 4. Non-blocking I/O The non-blocking nature makes node.js a good fit for comet and next generation realtime web- applications nginx: non-blocking apache: threaded non-blocking can handle more requests-per-second and uses a lot less memory
- 5. NodeJS Perks: front- and backend ● One Javascript - different approaches ● Common libs ● Unit-tests for both sides
- 6. NodeJS Perks: Frameworks Native example: var http = require('http'); http.createServer(function (req, res) { res.writeHead(200, { 'Content-Type': 'text/plain' }); res.end('Hello Worldn'); }).listen(3000, '127.0.0.1'); ExpressJS: var app = express.createServer(); app.get('/', function(req, res){ res.send('Hello World'); }); app.listen(3000);
- 7. NodeJS Perks: Comet Comet is a web application model in which a long-held HTTP request allows a web server to push data to a browser, without the browser explicitly requesting it. ● Comet servers need to have a lot of open connections ● One thread-per-connection does not scale ● The solution is to use event based servers ● It’s only possible to create event based servers in node.js
- 8. NodeJS Weaknesses ● Due to Javascript flexible nature it's hard to locate mistakes ● Strict convention rules are highly recommended ● One process serve plenty requests: so, mistake in one request may "freeze" other. ● Non-trivial garbage collector (closures, long-term processes) ● Strange open-source community (no standards) ● No backward compatibility
- 11. Resources 1. http://nodejs.org 2. www.nodebeginner.ru 3. http://pacemaker.pp.ua/presentations/Yura_Bogdanov-nodejs_inside_tactoom.ppt 4. http://code.google.com/p/v8/