This document provides an overview of Node.js and how to build server-side JavaScript applications with it. Some key points covered include: - Node.js uses a single-threaded non-blocking I/O model that handles multiple requests concurrently using callbacks and an event loop. - Common Node.js modules like Express make it easy to build REST APIs and web servers. Express uses middleware for common tasks like routing, static files, authentication etc. - Testing Node.js applications can be done with frameworks like Mocha and Chai to write unit and integration tests, and the Request library to mock HTTP requests.

1. node.js
practical guide to javascript on server

2. javascript fast/memory suck:(

3. node
V8
libuv
OS

4. single threaded/non blocking
OS
thread
f() f() f() f() f()
iocall1
iocall2
callback1
callback2

5. heavy functions block server
node
worker worker worker worker
so

6. what you shouldn't do with
node?
• real real time :)
• data bending

7. without streams
filesystem
web
nodeserver
nodeserver
filesystem
web
with streams
readStream.pipe(writeStream)
//file.pipe(response);
fs.read('filename',
function(data){
response.end(data);
})

8. modules
module.exports = function () {}
!
all modules should
be a single function
var
fs
=
require('fs');
fs.readFile('filename',
function(data){console.log(data)})
npm
install
express
-­‐-­‐save
{
"name":"pkgname",
"version":
"0.3.0",
"author":
"Eldar
Djafarov
<djkojb@gmail.com>",
"dependencies":{
"express":"3.4.0"
}
}

9. npm scripts
//use
npm
scripts
{
"scripts":{
"start":"node
start.js",
"test":"node
test.js",
"build":"grunt
build",
"build":"node
./node_modules/grunt-­‐cli/.bin/grunt
build"
}
}
$
npm
start
//
starts
an
app
$
npm
test
//
runs
tests
$
npm
run
build
//
builds
an
app

10. express deep dive
simple nodejs server
var
http
=
require('http');
http.createServer(function
(req,
res)
{
res.writeHead(200,
{'Content-­‐Type':
'text/plain'});
res.end('Hello
Worldn');
}).listen(1337,
'127.0.0.1');
console.log('Server
running
at
http://127.0.0.1:1337/');
simple express server
var
express
=
require('express');
var
app
=
express();
app.use(function
middleware(req,
res,
next){
//
do
stuff
next();
});
app.get('/',
function(req,
res,
next){
res.end('Hello
Worldn');
});
app.listen(1337);

11. opinionated top level app
architecture
SPA
REST
API
DB
Angularjs
or
backbone
node.js
express
mongoose
mongodb

12. express rendering
add engine
app.engine('jade',
require('jade').__express);
app.engine('html',
require('ejs').renderFile);
render templates
res.render('index',
function(err,
html){
res.send(html);
});
res.render('user',
{
name:
'Tobi'
},
function(err,
html){
res.send(html);
});

13. express deep dive
middleware concept
function
middleware(req,
res,
next){
doAsyncStuff(asyncStuffDone);
function
asyncStuffDone(err,
data){
if(err){
next(err);
}
next();
}
}
middleware
middleware
middleware
middleware
request
response

14. express deep dive
middleware concept
request middleware
middleware
middleware
middleware
app.router
GET /
POST /profile
middleware
middleware
middleware
middleware
middleware
middleware
app.use(middleware);
app.use(middleware);
app.use(middleware);
app.use(express.router)
app.get('/',
middleware,
middleware,...,middleware)
app.post('/profile',
middleware,
middleware,...,middleware)
app.use(middleware);
app.use(middleware);
app.use(middleware);

15. express deep dive
middleware concept
request middleware
static
middleware
middleware
app.router
GET /
POST /profile
middleware
middleware
middleware
middleware
middleware
middleware
app.use(middleware);
app.use(middleware);
app.use(middleware);
app.use(express.router)
app.get('/',
middleware,
middleware,...,middleware)
app.post('/profile',
middleware,
middleware,...,middleware)
app.use(middleware);
app.use(middleware);
app.use(middleware);
app.use(middleware);
!
app.use(express.static('./public'));
!
app.use(middleware);
app.use(middleware);
!
app.use('/static',express.static('./public'));
!
app.use(middleware);
or
serve
public
with
/static

16. express deep dive
middleware concept
request middleware
middleware
middleware
middleware
app.router
GET /
POST /profile
middleware
middleware
middleware
middleware
middleware
error
middleware
app.use(middleware);
app.use(middleware);
app.use(middleware);
app.use(express.router)
app.get('/',
middleware,
middleware,...,middleware)
app.post('/profile',
middleware,
middleware,...,middleware)
app.use(middleware);
app.use(middleware);
app.use(middleware);
module.exports
=
function(err,
req,
res,
next){
if(err){
if(err.isError){
return
res.json(err.code,
{err.reason});
}
}
res.json(500,
{
message:
'Something
is
terribly
wrong'
});
}

17. express deep dive
middleware concept
request middleware
middleware
auth middle
middleware
app.router
GET /
POST /profile
middleware
middleware
middleware
middleware
middleware
middleware
app.use(middleware);
app.use(middleware);
app.use(middleware);
app.use(express.router)
app.get('/',
middleware,
middleware,...,middleware)
app.post('/profile',
middleware,
middleware,...,middleware)
app.use(middleware);
app.use(middleware);
app.use(middleware);
authentication
function
authentication(req,
res,
next){
getUserBySessionId(req.session.uid,
gotUser);
function
gotUser(err,
user){
if(err)
return
next(err);
if(!user){
req.user
=
"guest";
}else{
req.user
=
user;
}
next();
}
}

18. express deep dive
middleware concept
request middleware
middleware
middleware
middleware
app.router
GET /
POST /profile
middleware
middleware
middleware
middleware
middleware
middleware
app.use(middleware);
app.use(middleware);
app.use(middleware);
app.use(express.router)
app.get('/',
middleware,
middleware,...,middleware)
app.post('/profile',
middleware,
middleware,...,middleware)
app.use(middleware);
app.use(middleware);
app.use(middleware);
authorization
app.get('/user/:id',
userAccessOnly,
featureAccess('getUser'),
getUser);
!
app.delete('/user/:id',
userAccessOnly,
featureAccess('deleteUser'),
deleteUser);
!
app.put('/profile',
userAccessOnly,
featureAccess('editProfile'),
validateProfile,
editProfile);
if(!req.user.features[feature]){
return
next(err.notAutorized())
}
if(!req.user){
return
next(err.noAuth());
}
next();
var
uid
=
req.param('id');
Users.delete(uid,
userGone);
function
userGone(err){
if(err)
next(err);
res.json({message:"OK"});
}

19. testing Use mocha + chai + request
describe("User
passes
authentication",
function(){
before(function(done){
request.post('/api/auth',
{form:{login:login,
pwd:password}},
authDone);
function
authDone(err,
response,
body){
expect(response).to.have.property('statusCode',
200);
done();
}
})
describe("GET
/api/users
tries
to
get
all
users",
function(){
var
users;
before(function(done){
request.get('/api/users',
gotUsers);
function
gotUsers(err,
response,
data){
users
=
data;
}
})
it('returned
data
should
be
json',
function(){
users
=
JSON.parse(users);
expect(users).to.be.an('object');
});
it('there
should
be
>
5
users',
function(){
expect(users).to.have.length.above(5);
})
...
})
})

20. RESTful webservices
Resources are nouns
HTTP request types are verbs
resource
POST
create
GET
read
PUT
update
DELETE
delete
/dogs
create new
dog
list dogs
bulk update
dogs
bulk
remove
dogs
/dogs/:id error read dog
update dog
if exists
else error
delete dog
GET /dogs?color=red&state=running&location=park
Complex stuff optional after ‘?’ sign
bitly.com/restfulApi

21. environment
Use flation/nconf module
var
APP_ENV
=
process.env.APP_ENV||'development';
nconf
=
require('nconf');
nconf.argv()
.env()
.file({file:'./config/'+APP_ENV+'.config.json'});
nconf.get('app:host');
nconf.get('app:port');
nconf.get('security:salt');

22. Q&A
СЛАВА УКРАЇНІ!
@edjafarov
eldar.djafarov.com