[TW] Node.js
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This document discusses server-side programming using Node.js. It introduces Node.js as an event-driven I/O framework for building scalable network programs using JavaScript on the server-side. It explains some of the key benefits of Node.js, including non-blocking I/O which allows supporting many concurrent connections without threads.
[TW] Node.js
- 1. Server Side Programming Using Node.JS Ana-Maria Daneliuc Bogdan Gaza TW2011
- 2. $whoarewe Students at Faculty of Computer Science ana.daneliuc@info.uaic.ro bogdan.gaza@info.uaic.ro TW2011
- 4. Java is to JavaScript Like ham is to hamster TW2011
- 5. JavaScript • Language of the Internet • Scripting language (interpreted) • Client side - usually run by the browser • Object oriented • Event driven TW2011
- 6. JavaScript • Growing in popularity • Big companies spend a lot of $$$ to improve JavaScript • Probably will become a very popular language TW2011
- 7. JavaScript • Until recent no clear - server side JavaScript console interpreter • Event driven on the server side also • Code sharing • All fast evented network servers were written in C/C++ TW2011
- 8. Node.JS Server Side JavaScript TW2011
- 9. Node.js • Event driven I/O framework • Build upon V8 engine • Server Side (includes system calls + different modules) • Intended for writing scalable network programs • Written in C/C++ and JavaScript TW2011
- 10. V8 TW2011
- 11. V8 JavaScript Engine • JavaScript VM used by Google Chrome • Written by one of the leading VM engineers with 20 years of building VMs - Lars Bak • The last VM written by Lars Bak - improved JavaScript 20x times. TW2011
- 12. V8 JavaScript Engine • JavaScript to assembler • Improved garbage collector • Independent from Google Chrome • Limitations: No bytecode/No threads/No processes TW2011
- 14. Blocking puts("Enter your name: "); var name = gets(); puts("Name: " + name); TW2011
- 15. Non-Blocking - Node.js way puts("Enter your name: "); gets(function(name){ puts("Name: " + name); }); TW2011
- 16. Remember Select From the “Retele” Node.js Course aka explain select say about poll/epoll When receiving data (from network / disk / another source) there must be a callback Data is received Data Event Source loop CallBack User Function TW2011
- 19. Node.js - Hello World 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/'); TW2011
- 21. Real time web applications TW2011
- 22. Ajax • Asynchronous JavaScript and XML • Method to load data asynchronously • Uses XMLHttpRequest object (from JS) • Nearly real time TW2011
- 23. Step 1 Loading Web Page Server TW2011
- 24. Step 2 Done Web Page Server Ajax Request TW2011
- 25. Step 3 Done Web Page Server Ajax Request TW2011
- 26. Step 4 Done Web Page Server Ajax Request TW2011
- 27. Step 5 Done Web Page Server Ajax Request For another request goto step 1 TW2011
- 28. Comet Long-lived HTTP connections Reduce latency Messages are passed from the server to the client PUSH TW2011
- 29. Step 1 Loading Web Page Server TW2011
- 30. Step 2 Done Web Page Server Long lived HTTP TW2011
- 31. Step 3 Event Done Web Page Server Long lived HTTP TW2011
- 32. Step 4 Done Web Page Server Long lived HTTP TW2011
- 33. Step 5 Done Web Page Server Long lived HTTP TW2011
- 34. Step 6 Done Web Page Server Long lived HTTP For another request goto step 1 TW2011
- 35. WebSockets • Use TCP sockets from the browser • Update web page 40 times / s • API is work in progress • Not supported by all the modern browsers TW2011
- 36. Ajax vs Comet vs WebSockets Ajax Comet WebSockets TW2011
- 37. DEMO TW2011
- 38. Q/A TW2011
- 39. Thanks! TW2011