Why Nodejs Guilin Shanghai

Why

by 桂林

桂糊涂@weibo
guilin1981@twitter

About me
2003, Delphi.

2006, Java.

2009, Python.

2010, Node.js.

Author of m on g osk in and st or m js

What is node.js?

Evented I/O
for
V8 JavaScript.

What can node.js do?
Node.js as webserver

C10k problem

C10k problem

Comet

C10k problem

Comet

Websocket

C10k problem

Comet

Websocket

Node.js as TCP server

C10k problem

Comet

Websocket


Node.js as CLI tools

C10k problem

Comet

Websocket


Node.js as CLI tools

Node.js as GUI tools

Why node.js
Wh y asy n c h r on ou s I O ?

Why asynchronous IO?
IO is the bottle-neck of application.

IO is the bottle-neck of application.
Network IO

File IO

Database IO

Blocking socket IO
class ServerThread extends Thread {
public ServerThread(socket){
this.socket = socket;
}
public void run(){
BufferedReader reader = new
BufferedReader(this.socket.getInputStream());
String line;
while((line = reader.readLine()) != null){ // block here
// handle line
}
}
}
...
ServerSocket serverSocket = new ServerSocket(port);
while (true) {
Socket s = serverSocket.accept(); // block here
new ServerThread(s).start();
}

Non-blocking socket IO
net.createServer(function(socket){
socket.on('data', function(data){
// handle data
});
socket.on('close', function(has_error){
// handle close
});
socket.on('error', function(err){
// handle error
});
}).listen(port);

Non-blocking IO vs Blocking IO

nginx(non-blocking) vs apache(blocking)

Node.js IO API
stream

fs

http

net

dns

Why node.js

Wh y javasc r ip t ?

Why javascript?
Browsers war improving javascript.

Why javascript?

Javascript is one of the f ast est dynamic programming language.

Why javascript?


Javascript is one of the m ost p op u lar programming language.

Why javascript?



Javascript has c losu r e (anonymoused function).

Why javascript?



Javascript has c losu r e (anonymoused function).

Javascript is cross-platform.

Why node.js

Why javascript?

Wh y v8 ?

About v8
V8 javascript VM is used in Goog le Ch r om e .

About v8

V8 team is led by L ar s B ak , one of the leading VM engineers in the
world with 20 years of experience in building VM.

About v8

V8 team is led by L ar s B ak , one of the leading VM engineers in the
world with 20 years of experience in building VM.

L ar s B ak was the t ec h n ic al lead behind HotSpot(Sun’s Java VM).
HotSpot improved Java’s performance 2 0 x t im es .

Before HotSpot, L ar s B ak worked on a sm allt alk VM .

How fast v8 is?
Fast Property Access

Dynamic Machine Code Generation

Efficient Garbage Collection

V8 example
The JavaScript code to access property x from a Point object is:
point.x

V8 example
The JavaScript code to access property x from a Point object is:
point.x

In V8, the machine code generated for accessing x is:
# ebx = the point object
cmp [ebx,<hidden class offset>],<cached hidden class>
jne <inline cache miss>
mov eax,[ebx, <cached x offset>]

Why node.js

Why javascript?

Why v8?

Wh y t h r ead less?

Why threadless?
2mb stack per thread

Why threadless?

Dead-locking

Why threadless?

Dead-locking

Thread-safe?

Why threadless?

Dead-locking

Thread-safe?

Thread is design for blocking IO.

Why node.js

Why javascript?

Why v8?

Why threadless?

Wh y n od e. js sp ec ial?

Why node.js special?
Pythoner:

Pythoner:
Python is one of the most popular dynamic language too.

Pythoner:

Performance of python is OK.

Pythoner:

Performance of python is OK.

We have good non-blocking web framework.

Tornado by facebook

Tornado is a non-blocking web server, open-source by facebook.

Hello Tornado
import tornado.ioloop
import tornado.web

class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello, world")

application = tornado.web.Application([
(r"/", MainHandler),
])

if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()

Hello Nodejs
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello Node.jsn');
}).listen(3000, "127.0.0.1");

Tornado with IO
import pymongo
import tornado.web

class Handler(tornado.web.RequestHandler):
@property
def db(self):
if not hasattr(self, '_db'):
# block here
self._db = pymongo.Connection(
host='127.0.0.1', port=27017).test
return self._db

def get(self):
try:
# block here
user = self.db.users.find_one({'username':
self.current_user})
self.render('template', full_name=user['full_name'])
except:
raise tornado.web.HTTPError(500)

Tornado with async IO
import asyncmongo
import tornado.web

class Handler(tornado.web.RequestHandler):
@property
def db(self):
if not hasattr(self, '_db'):
self._db = asyncmongo.Client(pool_id='mydb',
host='127.0.0.1', port=27017,
maxcached=10, maxconnections=50, dbname='test')
return self._db

@tornado.web.asynchronous
def get(self):
self.db.users.find({'username': self.current_user}, limit=1,
callback=self._on_response)

def _on_response(self, response, error):
if error:
raise tornado.web.HTTPError(500)
self.render('template', full_name=respose['full_name'])

Node.js with IO
Anonymoused function, is very important for Evented IO
var mongo = require('mongoskin'),
http = require('http'),
jade = require('jade'),
db = mongo.db('localhost/test');

http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/html'});
db.users.findOne({'username': req.session.current_user},
function(err, user){
jade.renderFile('template', {user: user}, function(err, html){
res.end(html);
});
});
}).listen(3000, "127.0.0.1");

What make node.js special?
Javascript is special.


Most of node.js modules are asynchronoused.



It’s easy to write threadless module.



It’s easy to write threadless module.

Node.js community is very active.

How many modules?

2320 modules can be
install via npm
2011, June 07.

Node.js community

What do you think
about node
community?

Arunoda:
Its the freedom followed by tools like github and npm. And everything
is growing fast.

Pau:
People is more open minded than in other programming communities.
There is people coming from ruby, python, c, haskell, java, erlang,
php…

Mikeal Rogers:
People using node.js are building stuff. the project seeks to make the
lives better of people building products.

Mikeal Rogers:
My experience with Python and Ruby is that their primary reason for
working on the project is around with a new language and/or vm. the
people who work on “core” don’t build products and probably never
will.

Mikeal Rogers:
My experience with Python and Ruby is that their primary reason for
working on the project is around with a new language and/or vm. the
people who work on “core” don’t build products and probably never
will.
Node.js is not a language and it doesn’t write it’s own vm. it’s not
attractive to people who don’t care about building stuff with it.

桂林:
潮不等于装13 , node.js很酷，也很务实。

Why node.js
Never blocking, cpu efficient

Why javascript?
Right and popluar language

Why v8?
Extremely fast VM

Why threadless?
Easy, memory efficient

Active and creative community

Why Nodejs Guilin Shanghai

Recommended

More Related Content

What's hot (20)

Viewers also liked (7)

Similar to Why Nodejs Guilin Shanghai (20)

More from Jackson Tian (12)

Recently uploaded (20)

Why Nodejs Guilin Shanghai