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![Streams var http = require('http'); var spawn = require('child_process').spawn; http.createServer(function(req, res) { var params = req.url.split('/'); var args = [params[1], '-resize', params[2], '-']; var convert = spawn('convert', args); convert.stdout.pipe(res); }).listen(8080);](https://image.slidesharecdn.com/nodejs-a-practical-introduction-oredev-111109110343-phpapp02/75/Nodejs-a-practical-introduction-oredev-45-2048.jpg)
Uploaded byFelix Geisendörfer
Nodejs a-practical-introduction-oredev
The document provides a practical introduction to Node.js, detailing its history, installation, and key features such as non-blocking I/O and the V8 JavaScript engine. It highlights use cases for Node.js, including web sockets, proxying data streams, and backend support for single-page applications, while also addressing scenarios where Node.js may not be suitable. Additionally, it introduces the npm package manager and resources for joining the Node.js community.
Nodejs a-practical-introduction-oredev
- 1. A practical introduction FelixGeisendörfer Øredev 09.11.2011 (v1)
- 2. @felixge Twitter / GitHub/ IRC Felix Geisendörfer (Berlin, Germany)
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- 7. Feb 16, 2009 RyanDahl starts the node project (first commit)
- 8. ~June, 2009 Discovered node.js(v0.0.6)
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- 11. Core Contributor & Module Author node-mysql node-formidable + 30 other modules
- 12. Sep 29, 2009 IsaacSchlueter starts the npm package manager (first commit)
- 13. Nov 7, 2009 Ryan’stalk at JSConf.EU gets people excited about node
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- 15. #2 2nd most watchedrepository on GitHub
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- 17. 0.6.0 was released4 days ago (Nov 5)
- 18. Companies using node •GitHub (for Downloads) • Palm/HP (in WebOS) • Yahoo! Mail • Dow Jones & Company (for WJS social site) • LinkedIn (Mobile Web App) • Rackspace (Cloudkick monitoring) • Voxxer (Push to Talk mobile app)
- 20. Installing $ git clone git://github.com/joyent/node.git $ cd node $ git checkout v0.6.0 $ ./configure $ sudo make install (windows users: download node.exe)
- 21. Hello World hello.js console.log('Hello World'); $node hello.js Hello World
- 22. Hello World (REPL) $ node > console.log('Hello World') Hello World
- 23. Http Server http_server.js var http= require('http'); var server = http.createServer(function(req, res) { res.end('Hi, how are you?'); }); server.listen(8080); $ node http_server.js $ curl localhost:8080 Hi, how are you?
- 24. “Come on, serverside JS has been around since 1996”
- 25. What is sospecial about node?
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- 27. Speed • Node cando ~6000 http requests / sec per CPU core (hello world, 1kb response,) • It is no problem to handle thousands of concurrent connections which are moderately active
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- 29. V8 JavaScript Engine •Developed by Google in Aarhus, Denmark for Google Chrome • Translates JavaScript in Assembly Code • Crankshaft JIT (enabled in 0.6.0 by default)
- 30. V8 JavaScript Engine •You can expect to be within ~10x of C performance usually • Certain code can run within 2-3x of C • Getting faster all the time
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- 32. Blocking I/O read_file_sync.js var fs= require('fs'); var one = fs.readFileSync('one.txt', 'utf-8'); console.log('Read file one'); var two = fs.readFileSync('two.txt', 'utf-8'); console.log('Read file two'); $ node read_file_sync.js Read file one Read file two
- 33. Non-Blocking I/O read_file_async.js var fs= require('fs'); fs.readFile('one.txt', 'utf-8', function(err, data) { console.log('Read file one'); }); fs.readFile('two.txt', 'utf-8', function(err, data) { console.log('Read file two'); }); $ node read_file_async.js Read file two Read file one
- 35. Blocking I/O Read one.txt(20ms) Read two.txt (10ms) Total duration (30ms)
- 36. Non-Blocking I/O Read one.txt(20ms) Read two.txt (10ms) Total duration (20ms)
- 37. Non-Blocking I/O • Closeto ideal for high concurrency / high throughput, single execution stack • Forces you to write more efficient code by parallelizing your I/O • Feels pretty much like AJAX in the browser
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- 39. WebSockets • Persistent connection between browser/server • Very hard / awkward to do on traditional stacks • Hard to scale on traditional stacks
- 40. Socket.IO (community module) • WebSocket • Adobe® Flash® Socket • AJAX long polling • AJAX multipart streaming • Forever Iframe • JSONP Polling Chooses most capable transport at runtime!
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- 42. “Streams are totime as arrays are to space.” -- Jed Schmidt @ JSConf.eu 2010
- 43. Streams in node.js • Readable • Writable • Both
- 44. Streams var http =require('http'); var server = http.createServer(function(req, res) { req.on('data', console.log); }); server.listen(8080); $ node stream.js & $ curl -F file=@stream.js localhost:8080 ------------------------------41e92562223e Content-Disposition: form-data; name="file"; filename Content-Type: application/octet-stream var http = require('http'); var server = http.createServer(function(req, res) {
- 45. Streams var http =require('http'); var spawn = require('child_process').spawn; http.createServer(function(req, res) { var params = req.url.split('/'); var args = [params[1], '-resize', params[2], '-']; var convert = spawn('convert', args); convert.stdout.pipe(res); }).listen(8080);
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- 48. NPM • Puts dependenciesin the right place, then gets out of your way • No modification of a global load path (require.paths is gone in 0.6.0) • 4700+ Modules in npm, > 10 new modules / day
- 49. So what isnode good for?
- 50. Use cases • WebSockets/Pushapplications • Proxying data streams • Backend for single page apps
- 51. Use cases • Spawningother programs (processes) to do work / IPC • Parallelizing I/O
- 52. So what isnode not good for?
- 53. Anti-Use cases • ActualRealtime Systems • Number crunching / huge in-memory datasets • (CRUD apps)
- 54. Join the Community •Mailing list (nodejs, nodejs-dev) • IRC (#node.js) - 700+ User online
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- 56. Questions? @felixge
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- 59. What’s next? • Domains •Improved Stream API