How does it work? What makes it different? When would you use it? And most importantly, why does it matter?

1. Introduction to
Node.js
How does it work? What makes it different? When would you use
it? And most importantly, why does it matter?
Girish
Gangadharan
@appoosa

2. What is Node.js?
Development platform
Event-
Non-blocking I/O
driven
model
Built on Chrome's JavaScript
engine
“Node.js is lightweight and efficient which makes it perfect
for building fast, scalable network applications that run
across distributed devices.”

3. Wait a minute….
Umm…not
really.

4. JavaScript on the server
JavaScript was supposed to
be a server-side language as
well.

5. Netscape Enterprise Server
“ Netscape Enterprise Server 2.0 is the first web server to
support the Java(TM) and JavaScript(TM) programming
languages, enabling the creation, delivery and management of
live online applications.
”(March
1996)
Source: http://www.thefreelibrary.com/NETSCAPE+INTRODUCES+NETSCAPE+ENTERPRISE+SERVER(TM)+2.0-a018056425

6. Traditional web servers
Anyway, let’s see how web servers work
currently…

7. Current setup
Request 1
Thread 1
…
Request 2
Thread 2
…
Request n
Typically
….
Each request to a traditional web
server gets handed over to a
thread (picked from a limited
thread pool) for processing.
Thread m
(m < n)
(for a busy site, m could be a fraction of n)

8. How does it scale?
So if there are 10,000 requests
coming in at the same time, and
each requires executing a longrunning task (DB
transactions, network I/O, etc.) ….

9. How does node.js address it?
So what does node.js bring to the table?
Single thread processing.

10. And how does it work?
behind the
scenes
Source: http://www.aaronstannard.com/post/2011/12/14/Intro-to-NodeJS-for-NET-Developers.aspx

11. Simple “hello world” app
hello-world app in
node.js
// Load the http module to create an http server.
var http = require('http');
// Configure the HTTP server.
var server = http.createServer(function (request, response) {
response.writeHead(200, {"Content-Type": "text/plain"});
response.end("Hello, world");
});
// Listen on port 8000, IP defaults to 127.0.0.1
server.listen(3000);
// Log message to the terminal
console.log("Server running at http://127.0.0.1:3000/");

12. Demo
Let’s write some code.

13. What makes it different?
It’s JavaScript! (everybody know JavaScript,
right?)
Single threaded (avoid concurrency issues)
(single threaded out of the box, but still supports multi-threading)
Super efficient (can handle 100s of 1000s of
connections/minute)
Great for real-time applications (because of low latency)
Vibrant community (15,000+ packages)
And….it’s FREE! (no licensing costs, no expensive dev
tools)

14. Why does it matter?
It matters because just like with any other
technology, Node.js is not perfect.
Don’t start using it because it’s new and
shiny.
for example, it’s not the best solution for CPU intensive requests
processing
We don’t need another bubble.

15. When should you use it?
Multi user, real time apps
- mobile games, collaboration tools, chat rooms, etc.
APIs exposing JSON based DBs
- no need to do any JSON conversion (since it’s JavaScript)
Data Streaming
- Can process files as they’re still being uploaded (using
Streams)
Single page apps
- AJAX heavy apps can benefit from node’s low response
times

16. We’re done
Questions
?
Girish
Gangadharan
@appoosa