Download as PDF, PPTX
![single source events
function
productsInCart(request,
response)
{
var
db
=
null,
user
=
null,
...
createDb()
handle(function(source,
event)
{
if
(event["name"]
===
"createDb")
{
if
(db
===
null)
{
db
=
event.data
createUser(request)
}
else
{
????
}
}
else
if
(event["name"]
===
"createUser")
{
if
(user
===
null)
{
user
=
event.data
...
}
else
{
???
}
...
}
else
{
source.push(event,
state)
}
},
"_initial")
}](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-20-2048.jpg)
![data streams
server.on("request",
function(request,
response)
{
var
chunks
=
[],
output
=
fs.createWriteStream("./output")
request.on("data",
function(chunk)
{
chunks
=
forEachLine(chunks.concat(chunk),
function(line)
{
output.write(parseInt(line,
10)
*
2)
output.write("n")
})
})
request.on("end",
function()
{
response.writeHead(200,
{
"Content-Type":
"plain/text"
})
response.end("OKn")
output.end()
server.close()
})
})
02#proxy_stream/proxy_stream.js](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-35-2048.jpg)
![game handler
(initial board/user)
resource.get("/board/:id",
function(request,
response)
{
var
board
=
boards.get(request.params["id"])
if
(board
===
undefined)
{
board
=
new
Board({
"id":
request.params["id"]
})
boards.add(board)
}
uuid(function(userId)
{
var
user
=
board.user(userId)
response.writeHead(200,
{
"Content-Type":
"application/json"
})
response.end(
JSON.stringify({
"board":
board,
"user":
user
})
)
})
})
05#tictactoe/server.js](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-53-2048.jpg)
![game handler
(make your move)
resource.post("/board/:id",
function(request,
response)
{
waitForBody(request,
function(body)
{
boards.get(request.params["id"]).move(JSON.parse(body))
response.writeHead(204,
{
"Content-Type":
"application/json"
})
response.end(JSON.stringify({
"response":
"ok"
}))
})
})
05#tictactoe/server.js](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-54-2048.jpg)
![in browser
routing
$(function()
{
$.sammy(function()
{
this.get("",
function(context)
{
$.post("/board",
function(response)
{
context.redirect("#/board/"
+
response["board"]["id"])
})
})
...
}).run()
})
05#tictactoe/static/board.html](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-57-2048.jpg)
![in browser
routing/start game
var
comet
=
new
Faye.Client("/comet")
var
game
=
new
Game()
this.get("#/board/:id",
function(context)
{
game.start()
$.get("/board/"
+
context.params["id"],
function(response)
{
game.set({
"me":
new
User(response.user)
})
game.set({
"board":
new
Board(response.board)
})
comet.connect()
comet.subscribe("/board-"
+
context.params["id"],
function(board)
{
game.get("board").set(board)
})
})
})
05#tictactoe/static/board.html](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-58-2048.jpg)
![in browser
game logic example
game.bind("play-with-board",
function(cells)
{
buildBoard(['_'].concat(cells))
})
game.bind("play-with-mark",
function(mark)
{
showPlayerMarker(cellMarksUrl[myMark
=
mark])
})
game.bind("make-your-move",
function()
{
$("#board").undelegate()
$("#board").delegate("*[id^=cell]",
"mouseover",
function()
{
$(this).data("cell").select()
})
$("#board").delegate("*[id^=cell]",
"mouseout",
function()
{
$(this).data("cell").unselect()
})
...
05#tictactoe/static/js/application.js](https://image.slidesharecdn.com/nodejsexplained-101116115055-phpapp02/75/Nodejs-Explained-with-Examples-60-2048.jpg)
Uploaded byGabriele Lana
Nodejs Explained with Examples
The document discusses Node.js and asynchronous I/O. It explains that Node.js is an asynchronous event-driven JavaScript runtime that uses a single-threaded model with non-blocking I/O to handle high volumes of simultaneous connections efficiently. It also discusses how Node.js handles asynchronous operations using an event loop and callback functions instead of blocking operations.
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Nodejs Explained with Examples
- 1. this presentation codeis on https://github.com/gabrielelana/node-examples
- 2. gabriele lana gabriele.lana@cleancode.it twitter: @gabrielelana this presentation code is on https://github.com/gabrielelana/node-examples
- 3. why node.js? “Node's goal is to provide an easy way to build scalable network programs” http://nodejs.org/#about
- 4. what is node.js? • asynchronous i/o framework • core in c++ on top of v8 • rest of it in javascript • swiss army knife for network related stuffs • can handle thousands of concurrent connections with minimal overhead (cpu/memory) on a single process
- 5.
- 6.
- 7.
- 8.
- 9. you can “always” scale with multiple machines but it costs you $$$
- 11. but... what is HE doing?
- 12. CPU BOUND TASKS? but... what is HE doing?
- 13. CPU BOUND TASKS? ...OR I/o but... BOUND what is HE TASKS? doing?
- 14.
- 15.
- 16.
- 17.
- 18.
- 19. single source events STATES EVENTS http://www.infoq.com/presentations/Death-by-Accidental-Complexity
- 20. single source events function productsInCart(request, response) { var db = null, user = null, ... createDb() handle(function(source, event) { if (event["name"] === "createDb") { if (db === null) { db = event.data createUser(request) } else { ???? } } else if (event["name"] === "createUser") { if (user === null) { user = event.data ... } else { ??? } ... } else { source.push(event, state) } }, "_initial") }
- 21. asynchronous I/0 single thread asynchronous I/0 I am “callback” call me if you need me...
- 22. asynchronous I/0 single thread asynchronous I/0
- 23. multiple source events (local state) STATES EVENTS
- 24. multiple source events (local state) function productsInCart(request, response) { createDb(function(db) { createUser(function(user) { if (user.isAuthorized("cart/products") { response.write( JSON.stringify( db.productsInCart(user.cartId()) ) ) response.end() }) else { response.unauthorized() } }) }) }
- 25. multiple source events (local state) function productsInCart(request, response) { createDb(function(db) { createUser(function(user) { if (user.isAuthorized("cart/products") { response.write( JSON.stringify( db.productsInCart(user.cartId()) ) ) response.end() }) else { response.unauthorized() } }) }) }
- 26. Event Emitter (local state) var http = require("http") var server = http.createServer(function(request, response) { response.writeHead(200, { "Content-Type": "plain/text" }) response.write("Hello Worldn") response.end() }) server.listen(8080) console.log("> SERVER STARTED") 01#hello_world/hello_world_server.js
- 27. Event Emitter (local state) var http = require("http") var server = http.createServer(function(request, response) { response.writeHead(200, { "Content-Type": "plain/text" }) response.write("Hello Worldn") response.end() }) server.listen(8080) console.log("> SERVER STARTED") 01#hello_world/hello_world_server.js
- 28. Event Emitter (local state) var http = require("http") var server = http.createServer(function(request, response) { response.writeHead(200, { "Content-Type": "plain/text" }) response.write("Hello Worldn") response.end() }) server.listen(8080) console.log("> SERVER STARTED") 01#hello_world/hello_world_server.js
- 29. Event Emitter (local state) var http = require("http") var server = http.createServer(function(request, response) { response.writeHead(200, { "Content-Type": "plain/text" }) response.write("Hello Worldn") response.end() }) server.listen(8080) console.log("> SERVER STARTED") 01#hello_world/hello_world_server.js
- 30. Event Emitter (local state) coder@apollo:~/Work/src/node/examples$ node hello_world_server.js > SERVER STARTED #1 coder@apollo:~$ curl "http://localhost:8080/" Hello World #2
- 31. Event Emitter (local state) var server = require("http").createServer() server.on("request", function(request, response) { console.log("> REQUEST STARTED") request.on("end", function() { console.log("> REQUEST CLOSED") response.writeHead(200, { "Content-Type": "plain/text" }) response.end("Hello Worldn") server.close() }) response.on("close", function() { console.log("> RESPONSE CLOSED") }) }) 01#hello_world/hello_world_server_emitter.js
- 32. Event Emitter (local state) ... server.on("close", function() { console.log("> SERVER CLOSED") }) server.on("listening", function() { console.log("> SERVER STARTED") }) server.listen(8080) 01#hello_world/hello_world_server_emitter.js
- 33. Event Emitter (local state) coder@apollo:~/Work/src/node/examples$ node hello_world_server.js > SERVER STARTED #1 coder@apollo:~$ curl "http://localhost:8080/" Hello World #2 #1 > REQUEST STARTED > REQUEST CLOSED > SERVER CLOSED
- 34.
- 35.
- 36. Event Emitter (local state) coder@apollo:~/Work/src/node/examples$ node stream_doubler.js #1 coder@apollo:~$ curl "http://localhost:8080/" --data $'1n2n3n' OK #2 coder@apollo:~/Work/src/node/examples$ cat output 2 4 6 #1
- 37. why javascript? • Friendly callbacks • ubiquitous (well known) • no I/o primitives • one language to rule them all
- 38. web applications before: a web mind shift #1 server with some application logic application Web server application application application
- 39. web applications after: an application mind shift #1 accessible over http web server application
- 40. web applications after: an application mind shift #1 that can communicate and collaborate with web server the world application
- 41. web applications before: stateful mind shift #2 • no easy to scale • no easy to reuse v M c
- 42. web applications before: stateful mind shift #2 • no easy to scale • no easy to reuse v M c conversation application state state
- 43. web applications before: stateful mind shift #2 • no easy to scale • no easy to reuse v M c tightly coupled
- 44. web applications after: stateless mind shift #2 • easy to scale • easy to reuse v http M c
- 45. web applications after: stateless mind shift #2 • easy to scale • easy to reuse v http M c conversation application state state
- 46. web applications after: stateless mind shift #2 http web server M http statefull connection • easy to scale M • easy to reuse
- 47.
- 48. tic - tac- toe
- 49. tic - tac- toe demo
- 50. INSTALL NPM (node packet manager) coder@apollo:~/Work/src/node/examples$ curl http://npmjs.org/install.sh | sh ... npm ok It worked coder@apollo:~/Work/src/node/examples$ npm list | wc -l 1776 coder@apollo:~/Work/src/node/examples$ npm install connect@0.2.5 coder@apollo:~/Work/src/node/examples$ npm install faye@0.5.3 coder@apollo:~/Work/src/node/examples$ npm install backbone@0.3.0 coder@apollo:~/Work/src/node/examples$ npm install underscore@1.1.2
- 51.
- 52. game handler (generate board-id) resource.post("/board", function(request, response) { response.writeHead(200, { "Content-Type": "application/json" }) uuid(function(boardId) { response.end( JSON.stringify({ "board": { "id": boardId } }) ) }) }) 05#tictactoe/server.js
- 53. game handler (initial board/user) resource.get("/board/:id", function(request, response) { var board = boards.get(request.params["id"]) if (board === undefined) { board = new Board({ "id": request.params["id"] }) boards.add(board) } uuid(function(userId) { var user = board.user(userId) response.writeHead(200, { "Content-Type": "application/json" }) response.end( JSON.stringify({ "board": board, "user": user }) ) }) }) 05#tictactoe/server.js
- 54. game handler (make your move) resource.post("/board/:id", function(request, response) { waitForBody(request, function(body) { boards.get(request.params["id"]).move(JSON.parse(body)) response.writeHead(204, { "Content-Type": "application/json" }) response.end(JSON.stringify({ "response": "ok" })) }) }) 05#tictactoe/server.js
- 55.
- 56. comet EVENTS on backbone events var client = comet.getClient() var boards = new Backbone.Collection boards.bind("change", function(board) { client.publish("/board-" + board.get("id"), board) }) 05#tictactoe/server.js
- 57. in browser routing $(function() { $.sammy(function() { this.get("", function(context) { $.post("/board", function(response) { context.redirect("#/board/" + response["board"]["id"]) }) }) ... }).run() }) 05#tictactoe/static/board.html
- 58. in browser routing/start game var comet = new Faye.Client("/comet") var game = new Game() this.get("#/board/:id", function(context) { game.start() $.get("/board/" + context.params["id"], function(response) { game.set({ "me": new User(response.user) }) game.set({ "board": new Board(response.board) }) comet.connect() comet.subscribe("/board-" + context.params["id"], function(board) { game.get("board").set(board) }) }) }) 05#tictactoe/static/board.html
- 59. in browser game logic example window.Game = Backbone.Model.extend({ "initialize": function() { ... game.get("board").bind("change", function() { if (this.isMyTurn()) { return game.trigger("make-your-move") } return game.trigger("wait-for-move") }) } }) 05#tictactoe/static/js/application.js
- 60. in browser game logic example game.bind("play-with-board", function(cells) { buildBoard(['_'].concat(cells)) }) game.bind("play-with-mark", function(mark) { showPlayerMarker(cellMarksUrl[myMark = mark]) }) game.bind("make-your-move", function() { $("#board").undelegate() $("#board").delegate("*[id^=cell]", "mouseover", function() { $(this).data("cell").select() }) $("#board").delegate("*[id^=cell]", "mouseout", function() { $(this).data("cell").unselect() }) ... 05#tictactoe/static/js/application.js
- 61. What about cpu bound tasks?
- 62. the fork be with you #!/bin/bash for count in `seq 1 100`; do echo $count sleep 0.1 done 03#long_running_jobs/long_running_job.sh
- 63. the fork be with you var spawn = require("child_process").spawn, server = require("http").createServer() server.on("request", function(request, response) { var job = spawn("./long_running_job.sh") job.stdout.on("data", function(tick) { response.write(tick) }) job.on("exit", function() { response.end() }) }) 03#long_running_jobs/long_running_server.js
- 64. the fork be with you coder@apollo:~$ ab -c 1 -n 1 "http://localhost:8080/" ... Concurrency Level: 1 Time taken for tests: 10.531 seconds ... coder@apollo:~$ ab -c 1 -n 2 "http://localhost:8080/" ... Concurrency Level: 1 Time taken for tests: 20.108 seconds ...
- 65. the fork be with you coder@apollo:~$ ab -c 2 -n 1 "http://localhost:8080/" ... Concurrency Level: 2 Time taken for tests: 10.634 seconds ... coder@apollo:~$ ab -c 100 -n 100 "http://localhost:8080/" ... Concurrency Level: 100 Time taken for tests: 11.198 seconds ... coder@apollo:~$ ab -c 500 -n 500 "http://localhost:8080/" ... Concurrency Level: 500 Time taken for tests: 31.082 seconds ...
- 66. enter comet w at at ch watch ch M spawn w watch w w t a at ch ch
- 67.
- 68.
- 69.
- 70.
- 71.
- 72. node.js is awesome but when should i use it?
- 73. when to useit? • chat/messaging • real-time applications • intelligent proxies • high concurrency applications • communication hubs • coordinators
- 74. please tell me something bad about node.js
- 75. some warnings • release stable 0.2.4 (young) • lots of stuffs to look at • lots of half backed stuffs • retro compatibility??? • bad at handling static contents • hard to find organized and authoritative informations
- 77.
- 78. gabriele lana gabriele.lana@cleancode.it twitter: @gabrielelana this presentation code is on https://github.com/gabrielelana/node-examples