Simple CRUD app using REST api part - 1

• What is REST?

• Best thing ever. makes developers life much easier.

• REST means Representational State Transfer 

• You can simply make a CRUD app using this.



REST API Architecture





• Client makes HTTP requests to the API

• API handles Routes,Business Logic

• Sends and retrieve data from the database.

• This is simple, scalable and reliable.

• We are going to make a simple REST app using Node Express framework and MongoDB.
• First you have follow these and setup the project.

1. First you have setup node and create a project. I have explained this in my Node.js for dummies post.
2. Then you have to setup MonogoDB and keep it running. I have explained this in my MongoDB for dummies post
3. You need a postman app for testing HTTP requests. Download  it from  here.
4. And you need Robo 3T app for MongoDB GUI supporter. Thank me later for this Robo 3T.

• Now lets get our hands dirty,

• First we add express frame work to our project

npm install express --save

• this --save adds the dependency or "external resources" to package.json file in the project.

Now we can start development,

• First thing to be done is import the dependency, by requiring it on the top of the project. otherwise we cannot use express.

const express=require('express');

• I declare it as constant, because this variable should be declared only once.
• Then i create an instance of the app.

const app=express();

• And now app contains all the properties functions of an express app.

{ [EventEmitter: app]

  domain: undefined,

  _events: { mount: [Function: onmount] },

  _maxListeners: undefined,

  setMaxListeners: [Function: setMaxListeners],

  getMaxListeners: [Function: getMaxListeners],

  emit: [Function: emit],

  addListener: [Function: addListener],

  on: [Function: addListener],

  prependListener: [Function: prependListener],

  once: [Function: once],

  prependOnceListener: [Function: prependOnceListener],

  removeListener: [Function: removeListener],

  removeAllListeners: [Function: removeAllListeners],

  listeners: [Function: listeners],

  listenerCount: [Function: listenerCount],

  eventNames: [Function: eventNames],

  init: [Function: init],

  defaultConfiguration: [Function: defaultConfiguration],

  lazyrouter: [Function: lazyrouter],

  handle: [Function: handle],

  use: [Function: use],

  route: [Function: route],

  engine: [Function: engine],

  param: [Function: param],

  set: [Function: set],

  path: [Function: path],

  enabled: [Function: enabled],

  disabled: [Function: disabled],

  enable: [Function: enable],

  disable: [Function: disable],

  acl: [Function],

  bind: [Function],

  checkout: [Function],

  connect: [Function],

  copy: [Function],

  delete: [Function],

  get: [Function],

  head: [Function],

  link: [Function],

  lock: [Function],

  'm-search': [Function],

  merge: [Function],

  mkactivity: [Function],

  mkcalendar: [Function],

  mkcol: [Function],

  move: [Function],

  notify: [Function],

  options: [Function],

  patch: [Function],

  post: [Function],

  propfind: [Function],

  proppatch: [Function],

  purge: [Function],

  put: [Function],

  rebind: [Function],

  report: [Function],

  search: [Function],

  subscribe: [Function],

  trace: [Function],

  unbind: [Function],

  unlink: [Function],

  unlock: [Function],

  unsubscribe: [Function],

  all: [Function: all],

  del: [Function],

  render: [Function: render],

  listen: [Function: listen],

  request: IncomingMessage { app: [Circular] },

  response: ServerResponse { app: [Circular] },

  cache: {},

  engines: {},

  settings:

   { 'x-powered-by': true,

     etag: 'weak',

     'etag fn': [Function: generateETag],

     env: 'development',

     'query parser': 'extended',

     'query parser fn': [Function: parseExtendedQueryString],

     'subdomain offset': 2,

     'trust proxy': false,

     'trust proxy fn': [Function: trustNone],

     view: [Function: View],

     views: 'F:\\Projects\\Node\\REST-app1\\views',

     'jsonp callback name': 'callback' },

  _eventsCount: 1,

  locals:

   { settings:

      { 'x-powered-by': true,

        etag: 'weak',

        'etag fn': [Function: generateETag],

        env: 'development',

        'query parser': 'extended',

        'query parser fn': [Function: parseExtendedQueryString],

        'subdomain offset': 2,

        'trust proxy': false,

        'trust proxy fn': [Function: trustNone],

        view: [Function: View],

        views: 'F:\\Projects\\Node\\REST-app1\\views',

        'jsonp callback name': 'callback' } },

  mountpath: '/' }

• You can see it all. Don't get confused. Only for GEEKS.

• Now we have setup our app.
• We have to listen to incoming requests on a port.
• But how do we listen to incoming requests.

app.listen(process.env.port||3000,function () {

console.log("listeing on port 3000");

});

• This  code does that for us. the process.env.port||3000
• This tell us to listen on port 3000 or port on the web server environment that the app can listen to requests.