The document discusses starting a Node.js community project called Seneca. Seneca is described as a toolkit that allows building a startup minimum viable product in a weekend. It encourages participants to sign up via Twitter or email and contribute code to the GitHub repository. The document provides an overview of Node.js modules and how to create, publish and use them as part of developing the Seneca project.

1. seneca
nodejsdublin
16 August 2012
Richard Rodger
@rjrodger

2. hello
nodejsdublin
• let's start a community project
• how Node.js modules work
• introducing the seneca module

3. getting
started
• how do you learn Node.js?
• how do you contribute to Node.js?
• how do you get a job doing Node.js?

4. your
community
• nodejsdublin is for you
• here to help you learn
• here to build a great community

5. let's start
a project
• less talking, more coding!
• community project with many coders
• something with lots of small pieces

6. seneca
• A Minimal Viable Product toolkit
• let's you build a startup in a weekend :)
• for more about MVPs: http://bit.ly/N25FlZ

7. • Lucius Annaeus Seneca, 4 BC – AD 65
• You have to be stoic to do a startup
• "increases are of sluggish growth, but the way to
ruin is rapid"
* http://cassandralegacy.blogspot.ie/2011/08/seneca-effect-origins-of-collapse.html

8. sign up
• Tweet @nodejsdublin with #seneca
• Mail me: richard.rodger@nearform.com
• Code: github.com/nodejsdublin/seneca

9. node.js
modules
• basic building blocks of Node.js apps
• no special syntax; plain old JavaScript
• no version conflicts!

10. using modules
var _ = require("underscore");
var threes = _.map([1, 2, 3], function(n){ return n*3 });
console.log( threes );
// prints [3, 6, 9]
var mongo = require('mongodb');
var host = 'localhost';
var port = 27017;
var db = new mongo.Db( 'mydatabase',
new mongo.Server(host, port, {}), {});
db.open(function(err, db) { ... }

11. cool
modules
• express - JSP/ASP style dynamic server-side pages
• socket.io - HTML5 real-time web sockets that "just work"
• request - easy outbound calls to web services

12. using npm
• npmjs.org - module repository of record
• usage: npm install modulename
• modules live in local node_modules folder

13. how to pick
a module
• serious modules are on https://github.com/joyent/node/wiki/modules
• popularity! check watchers/issues on github
• documentation, including third party blogs
• ask the community: http://nodejs.org/community/

14. why npm
rocks
• modules are installed separately for each project
• dependencies are also installed separately
• no global conflicts, no cross-dependency
conflicts

15. package.json
• defines a module; lists dependencies
• always create one for each project
• npm install will set up dependencies for you!

16. package.json
{
"name" : "optimist",
"version" : "0.3.4",
"description" : "Light-weight option parsing.",
"main" : "./index.js",
"dependencies" : {
"wordwrap" : ">=0.0.2"
},
"repository" : {
"type" : "git",
"url" : "http://github.com/substack/node-optimist.git"
},
"keywords" : [ "argument", "args", "option", "parser" ]
"author" : { "name" : "James Halliday" },
"engine" : { "node" : ">=0.4 }
}

17. write a
module
• create a project on github
• npm init - creates package.json for you
• start with lib/modulename.js

18. modulename.js
"use strict";
function ModuleName() {
var self = {};
var private = "hidden";
self.member = "data";
self.method = function() { ... };
return self;
}
exports.ModuleName = ModuleName
callingcode.js
var modulename = require('modulename')
var instance = new modulename.ModuleName()

19. parambulator
• written just for this meetup! - sanity checks JSON data structures
• https://github.com/rjrodger/parambulator
• you also need a README.md and LICENSE.txt
• you really should have unit tests; try the vows module

20. file structure
parambulator /
package.json
README.md
LICENSE.txt
lib /
parambulator.js

21. publishing a
module
• the package.json files property is your friend
• register for an account on npmjs.org
• npm publish
• sit back and bask in the glory...

22. seneca
• nearForm builds web/mobile services
• shared set of features every startup needs
• ... must resist ... let's build a framework!

23. shared
features
• user accounts: login/logout, profile pages, social media, ...
• email: transactional, promotional, ...
• e-commerce: gateways, app stores, ...
• admin: data editors, analytics, audit logs, ..

24. seneca is in
production
businesspost.ie chartaca.com stanzr.com

25. command
pattern
• actions are represented by a set of properties
• seneca "executes" them by invoking plugins
• everything that happens is traceable
• business logic is insulated from service providers

26. seneca commands
// register a new user
seneca.act({
on: 'user',
cmd: 'register',
email: 'alice@example.com',
name: 'Alice',
password: '1234',
active: true
},
function(err, result) { ... })
// send an email
seneca.act({
on: 'email',
cmd: 'send',
to: 'alice@example.com',
code: 'thanks-for-registering',
fields: {name:'Alice'}
},
function(err, result) { ... })

27. plugins
• everything is a plugin
• plugins provide actions
• plugins are just modules!

28. seneca plugin
function EchoPlugin() {
var self = {};
self.name = 'echo';
self.init = function(seneca,opts,cb) {
seneca.add({on:'echo'}, function(args,seneca,cb){
var out = args
cb(null,out)
})
cb()
}
self.service = function() {
return function(req,res,next){
if( '/echo' == req.url ) {
res.writeHead(200);
res.end(req.url);
}
else next();
}
}
}
exports.plugin = function() {
return new EchoPlugin()
}

29. shared
data model
• Built-in ODM - Object Document Mapper
• You need this to stay sane
• ActiveRecord-ish API with MongoDB-ish queries

30. seneca data model
var product = seneca.make('product');
product.name = 'Apple';
product.price = 1.99;
product.save$(function(err,savedproduct){
console.log('generated id: '+savedproduct.id);
})
product.load$('1234',function(err,foundproduct){
console.log('found product '+foundproduct);
})
product.list$( {price:1.99}, function(err,list){
for( var i = 0; i < list.length; i++ ) {
console.log( list[i] );
}
})

31. what we
•
have now
messy code that kinda sorta works
• a few hackety hack plugins
• no documentation!

32. what we
need
• plugins! plugins! plugins!
• documentation ( ... just kidding! I'll do that)
• some nodeknockout.com entries -
November 10-12th! Fame & Glory Await!

33. let's code!
• Tweet @nodejsdublin with #seneca
• Mail me: richard.rodger@nearform.com
• Code: github.com/nodejsdublin/seneca