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Node.js
an introduction to
Humans,Networks and Chaos
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Don’t believe
Hype
The
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Chat!
Let’s
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>10 PRINT "HELLO LWSG!";
>20 GOTO 10
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Room
You are in a
with 2 exits
Left or right?
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Input / Output
Logic
Left
You
found
the
Princess!
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Map scenarios
Write code
Easy!
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Scenario: Player Turns Left
Given I am asked to turn left or right
When I choose to turn left
Then I should see “Eaten by a dragon”
Scenario: Player Turns Right
Given I am asked to turn left or right
When I choose to turn left
Then I should see “You found the Princess”
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Stop playing
with yourself.
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Stop playing
with yourself.
More difficult.
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Atari
Joystick Joystick
Input(s)
Logic
Output
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8 way joystick
2 buttons
2 players
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8 way joystick
2 buttons
2 players
Unpredictable
Humans
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Xbox
Controller
Internet
Map scenarios for this
Game Servers
Databases
Chat Servers
Voice Servers
Load balancers
Message queues
.. more
8 million
controllers
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Concurrency
Fork
Synchronous
Threads
Single-thread Events
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Concurrency
This is hard
Node.js
is a response
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Events
Browsers
Humans
It works.
JavaScript
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Event loop
Single threaded
Don’t block
Return fast
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thread
One
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thread
One
INSANE?
Are
YOU
And JavaScript?
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Performance
http://blog.webfaction.com/a-little-holiday-present
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Memory
http://blog.webfaction.com/a-little-holiday-present
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Web
is changing (again)
The
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Network
EVERYTHING
Phones
Tablets
TVs
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Toasters
Bus stops
Cars
Billboards
Fridges
Network
EVERYTHING
APIs
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Turn left or right?
Server
Browser
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Still ok?
Server
Browser
DB
Server
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Still ok?
Browser Server
App Servers
Databases
Chat Servers
Voice Servers
Load balancers
Message queues
3rd party APIs
..more
Unlimited things
Millions of users.
Phones, Tablets, TVs
Billboards, Fridges
more..
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Chaos
Data flow
Networks
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Chaos
Data flow
Humans
Networks
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Push
Real-time
Networked
High concurrency
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I/O
event-driven
Non-blocking
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I/O
event-driven
Non-blocking
What?
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With Javascript.
@hij1nx
That is all.
Network programming.
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V8
Brains
FAST
Networks
Performance
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JavaScript
EVENTED
JSON
Browsers
Mis- Well understood
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var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(1337, "127.0.0.1");
console.log('Server running at http://
127.0.0.1:1337/');
HelloWorld
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HelloWorld
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World\n');
}).listen(1337, "127.0.0.1");
console.log('Server running at http://
127.0.0.1:1337/');
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Callbacks
Do something
when you
FINISH
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$("p").hide(1000);
alert("The paragraph is now hidden");
$("p").hide(1000,function(){
alert("The paragraph is now hidden");
});
Callbacks in jQuery
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var urls = db.query("select * from urls");
urls.each(function () {
var page = http.get(url);
save(page);
});
db.query("select * from urls", function (urls) {
urls.each(function(url) {
http.get(url, function (page) {
save(page);
});
});
});
Jacek Becela http://www.slideshare.net/jacekbecela/introduction-to-nodejs
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var urls = db.query("select * from urls");
urls.each(function () {
var page = http.get(url);
save(page);
});
db.query("select * from urls", function (urls) {
urls.each(function(url) {
http.get(url, function (page) {
save(page);
});
});
});
http://www.slideshare.net/jacekbecela/introduction-to-nodejs
Blocking
Blocking
Blocking
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var urls = db.query("select * from urls");
urls.each(function () {
var page = http.get(url);
save(page);
});
db.query("select * from urls", function (urls) {
urls.each(function(url) {
http.get(url, function (page) {
save(page);
});
});
});
http://www.slideshare.net/jacekbecela/introduction-to-nodejs
Blocking
Blocking
Blocking
Callbacks
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Head
Hurts
Show
Me
something FUN
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Forget order
Embrace
Random
Events
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Where next?
Express (gateway drug) - http://expressjs.com
Socket.io (fast high) - http://socket.io/
dnode (blows mind) - https://github.com/substack/dnode
UK Training http://leftlogic.com/training#node
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Thanks!
@shapeshed
Slides: bit.ly/A8azQ7
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