A language for the Internet: Why JavaScript and Node.js is right for Internet Applications
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Node.js and JavaScript are well-suited for Internet applications because Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, capable of supporting many more concurrent connections than traditional server-side models like Apache. This event loop system allows Node.js to handle multiple requests simultaneously without blocking any specific request. It also minimizes memory usage so more requests can be served from fewer servers.
![Enki:~ $ node
> var foo = "bar";
> foo;
'bar'
> .clear
Clearing context...
> foo
ReferenceError: foo is not defined
at [object Context]:1:1
at Interface.<anonymous> (repl:98:19)
at Interface.emit (events:27:15)
at Interface._ttyWrite (readline:295:12)
at Interface.write (readline:132:30)
at Stream.<anonymous> (repl:79:9)
at Stream.emit (events:27:15)
at IOWatcher.callback (net:489:16)](https://image.slidesharecdn.com/web2-sf-11-110329123847-phpapp02/85/A-language-for-the-Internet-Why-JavaScript-and-Node-js-is-right-for-Internet-Applications-47-320.jpg)
A language for the Internet: Why JavaScript and Node.js is right for Internet Applications
- 1. A language for the Internet Why JavaScript and Node.js is right for Internet Applications Tom Hughes-Croucher @sh1mmer
- 5. Scalable Server-Side Code with JavaScript Node Up and Running Tom Hughes-Croucher
- 6. A brief aside. A small lecture on biology
- 7. The common tree shrew
- 8. Diana Monkey
- 11. Back to your feature presentation.
- 12. Internet?
- 21. More features More users More devices More data
- 22. Cost Stuff
- 23. How do we cope with the increase in demand?
- 26. Browser Server Spidering... The Web
- 28. Browser Front-end Server Computation Database
- 29. Computational Computing Client → Server Computation
- 30. Internet Computing Client → Server Server → DB Computation Computation
- 33. Server
- 34. Request
- 37. U L L F
- 39. Place- holder
- 43. Node.js? • Server Side JavaScript runtime • Built on top of V8 JavaScript engine from Google Chrome • Non-blocking I/O APIs • Easy to extend APIs and modules
- 44. $Enki:~ $ node
- 45. $Enki:~ $ node >3>2>1 false > true == 1 true > true === 1 false
- 46. > console.log('Hello World'); Hello World > .help .clear Break, and also clear the local context. .exit Exit the prompt .help Show repl options > .clear Clearing context... > .exit Enki:~ $
- 47. Enki:~ $ node > var foo = "bar"; > foo; 'bar' > .clear Clearing context... > foo ReferenceError: foo is not defined at [object Context]:1:1 at Interface.<anonymous> (repl:98:19) at Interface.emit (events:27:15) at Interface._ttyWrite (readline:295:12) at Interface.write (readline:132:30) at Stream.<anonymous> (repl:79:9) at Stream.emit (events:27:15) at IOWatcher.callback (net:489:16)
- 48. var http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }).listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/');
- 49. var http = require('http'); //include the http library
- 50. http.createServer(function (req, res) { }).listen(8124, "127.0.0.1"); //create an http server //when ‘stuff’ happens call this anonymous function //listen on port 8124 of the IP 127.0.0.1
- 51. http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }) //when ‘stuff’ happens my function fires //I get a request object and a response object //I write to the response object header //HTTP status 200 and content-type ‘text/plain’ //close the response with the body: //Hello World
- 52. console.log('Server running at http://127.0.0.1:8124/'); //write Server is running at http://127.0.0.1:8124/ //to the console
- 53. Why is Node.js suited to Internet Apps?
- 55. What is the event loop?
- 57. Multi-tasking, one thing at a time.
- 60. var http = require('http'); server = http.createServer(); server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/');
- 61. var http = require('http'); server = http.createServer(); server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 1. Evaluate 'Main'
- 62. var http = require('http'); server = http.createServer(); server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 1. variables: http -> http module server -> http server listeners: server.request -> function
- 63. var http = require('http'); server = http.createServer(); * server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 2. Event Loop
- 64. var http = require('http'); server = http.createServer(); * server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 2. Do we have active listeners? listeners: server.request -> function Yes! Wait for listeners.
- 65. var http = require('http'); server = http.createServer(); server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 3. Event Calls
- 66. var http = require('http'); server = http.createServer(); server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 3. 'request' is called. Since listeners: server.request -> function Call function
- 67. var http = require('http'); server = http.createServer(); server.on('request', function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }); server.listen(8124, "127.0.0.1"); console.log('Server running at http://127.0.0.1:8124/'); Step 3. Loop! (go to Step 2.)
- 68. Breaking the event loop
- 70. EE = require('events').EventEmitter; ee = new EE(); die = false; ee.on('die', function() { die = true; }); setTimeout(function() { ee.emit('die'); }, 100); while(!die) { } console.log('done');
- 71. Why non-blocking matters
- 72. var result = db.query("select * from T"); // use result
- 73. What are we waiting for?
- 75. "Blocking" is as bad as stopping
- 76. Event Loop vs. Threads
- 77. PHP 8mb 8gb ram 8000/8 = 1000 ~1000 users per machine
- 78. Node.js TCP = 2kb HTTP = 6kb 8gb ram 8000/0.006 = 1.3m 1.3m/2 ~ 650k users
- 79. Apache vs NGINX concurrency × reqs/sec http://blog.webfaction.com/a-little-holiday-present
- 80. Apache vs NGINX concurrency × memory http://blog.webfaction.com/a-little-holiday-present
- 81. Node.js is designed for communication, just like your applications
- 82. Thanks!
- 83. Follow me @sh1mmer Tom Hughes-Croucher @sh1mmer
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