Node.js - Why JavaScript on the Server isn't as Bad an Idea as it Sounds

A quick introduction to Node.js, how it works, and how it's being used, aiming to dispel the FUD from the haters and the zealots.

Transcript

1. Working with Node Why javascript on the server is not as terrible as it sounds
2. Node.js X X
3. Node.js = Google V8 event reactor + core library + “a binding to V8 JavaScript for scripting network programs” - Ryan Dahl
4. What’s V8? •Not a tomato drink •Google’s JavaScript engine •Compiles JS to machine code •The gift of the browser wars!
5. What’s V8?
6. Ludicrous Speed! REALLY fast for a dynamic language http://shootout.alioth.debian.org/
7. Web Apps 101 •How to handle lots of web requests? •Prefork processes •Thread pool or spawning •Scaling FTW!
8. Web Apps 101 •But... what about LOTS of concurrent requests? •Context switching threads can be slow •And what if each request needs file or network IO? •Serial processes can take too long to execute •Scaling... uh-oh
9. Enter the Event Reactor! •One process per core, single thread per process •Start handling a request, pass it off, handle the next, go back to the first
10. Sound familiar? •Apache - prefork processes or thread based scaling •Nginx - event reactor
11. Node.js Event Reactor •Async IO with callbacks •Concurrent, not parallel! •Your code is still serial
12. Node.js Event Reactor •Scale horizontally by spawning child processes •cluster.fork() allows message passing and TCP sharing •But what about shared state? HATEOAS
13. But Why JAVASCRIPT?! •Async coding is the JS norm •First class functions •Proper closures
14. Events all the way down
15. Node.js core present low level interfaces and minimize abstractions “Node makes what was previously merely configurable into something more programmable, orthogonal, and more powerful.” - James Halliday (@substack)
16. Node.js core •qualified imports •callbacks •requests passed from function to function
17. NPM - Node’s Best Friend
18. NPM •Dependencies installed locally •Conflicting sub-dependencies are ok! •Libraries are easy to debug and monkeypatch “Concurrent versioning and locality preference drastically accelerate the rate that we can iterate on new experiments and the levels of reuse that we can attain both in a single large project and among projects.” - @substack
19. Node.js in Action •Web servers: Connect, Express •Testing: Jasmine, Vows, Vows-BDD •CLI: Commander.js
20. Node.js in Action
21. Node.js in Action
22. Callbacks. Yuck. •Use named functions •Use a control flow library like async.js
23. Worth the hype? •Yes and no. •The Typesafe stack is pretty awesome •Learn more about node! •Node docs - http://nodejs.org/ •“How to node” blog - http:// howtonode.org/ •Docs and guide: http://nodemanual.org •Node knockout app - https://github.com/ nko2/website/