• Representational state transfer
  
• Defined in 2000 by Roy Fielding
  
• Architectural constraints
  
• Client–server
  
• Stateless
  
• Cacheable
  
• Layered
  

• Objects are known as resources
• CRUD operations done by HTTP verbs:
• POST - Create
• GET - Read
• PUT, PATCH - Update
• DELETE - Delete
• For example, a bookstore inventory might support operations like:
• POST /book
• GET /book/12345

• For some REST is a rigidly defined architecture. That's fine!
• For others REST is a concept used to communicate a style. This is also fine!
• Be as pragmatic or dogmatic about REST as you want, there are no moral absolutes in software design.

• A web application framework for node
• Makes handling HTTP/S requests easy with middleware
• Lots of built in functionality 
• If you are handling HTTP requests, use Express.

var express = require('express');
var app = express();
app.post('/book', function(req, res){
  // Connect to a data source, create a book, assign to variable book
  res.json(201, book);
});
app.get('/book/:id', function(req, res){
  // Connect to a data source, read a book by id, assign to variable book
  res.json(200, book);
});
app.put('/book/:id', function(req, res){
  // Connect to a data source, update a book by id, assign to variable book
  res.json(200, book);
});
app.delete('/book/:id', function(req, res){
  // Connect to a data source, delete a book by id
  res.send(204);
});
app.listen(3000);  

This works, but is not sustainable.

var express = require('express');
var book = require('./book.js');
var app = express();
app.post('/book', book.create);
app.get('/book/:id', book.fetch);
app.put('/book/:id', book.update);
app.delete('/book/:id', book.destroy);
app.listen(3000); 

Much better, but still cumbersome for multiple services.

• Extensible Web Service Controller
• Offloads tasks common to services
• Authentication
• Authorization
• Encoding
• Content Negotiation/Enforcement
• CORS
• Routing
• Each service loaded as a module
• Scale services separately
• More granular source code access

• Boss Service Module requires a boss.json manifest file.
  
• Declares resources and where to find resource methods.
  

{
  "resources": [
    {
      "name" "book",
      "methods": "./book.js"
    },
    {
      "name": "author",
      "methods": "./author.js"
    }
  ]
} 

• Methods defined for each resource operation
  

exports.create = function(req, res){
  // Connect to data source, create a book, assign to variable book
  res.json(201, book);
};
exports.fetch = function(req, res){
  // Connect to data source, read a book by id, assign to variable book
  res.json(200, book);
};
exports.update = function(req, res){
  // Connect to data source, update a book by id, assign to variable book
  res.json(200, book);
};
exports.destroy = function(req, res){
  // Connect to data source, delete a book by id
  res.send(204);
}; 

var fs      = require('fs');
var express = require('express');
var config  = require('config');
var auth    = require('./auth.js');

services = fs.readdirSync(config.serviceDir);
services.forEach(function(service) {
var versions = fs.readdirSync(config.serviceDir+"/"+service);
  versions.forEach(function(version) {
  var serviceConfig = JSON.parse(fs.readFileSync(config.serviceDir+"/"+service+"/"+version+"/"+config.serviceFile))
  serviceConfig.resources.forEach(function(resource) {
    resource.path = "/"+service+"/"+version+"/"+resource.name;
      app.post(resource.path, auth.authenticate, auth.authorize, resource.methods.create);
      app.get(resource.path + '/:id', auth.authenticate, auth.authorize, resource.methods.fetch);
      app.put(resource.path + '/:id', auth.authenticate, auth.authorize, resource.methods.update);
      app.delete(resource.path + '/:id', auth.authenticate, auth.authorize, resource.methods.destroy);
    })
  })
});  

var server = app.listen(config.net.port, function() {
    console.log('Listening on port %d', server.address().port);
});