Required NPM Packages
Throughout our examples, some required npm packages need to be installed, some of them can be installed by npm – build-in package management tool, and the remaining are bundled with Node.js . Please find the below packages and their details:
| Package | Express |
| NPM Install | npm install express |
| Functions | Provide the coding framework |
| Usage | Create the URL routing by:
var express = require(‘express’); var router = express.Router(); … //define the controller’s method and map the request URL ‘/’ to this method router.get(‘/’, function(req, res) |
| Package | body-parser |
| NPM Install | npm install body-parser |
| Functions | Being a middleware to extract incoming request, in order to parse POST data from req.body . |
| Usage | var bodyParser = require(‘body-parser’);
… app.use(bodyParser.json()); app.use(bodyParser.urlencoded({ extended: true })); … //Getting parameters values from req.body var customer = new Customer(0, req.body.firstname, req.body.lastname, req.body.telephone, req.body.email, req.body.age, req.body.gender, req.body.username, req.body.password); |
| Package | ejs |
| NPM Install | npm install ejs |
| Functions | Providing template feature |
| Usage | //Define the template path, and tell Node.js that it is using ejs as view engine
app.set(‘views’, __dirname + ‘/app/views’); app.set(‘view engine’, ‘ejs’); … //Output the results to related ejs template res.render(‘customer/new‘, { title: ‘New Customer’, msgType: ”, msg: ”, customer: customer}); |
| Package | fs |
| NPM Install | Node.js built-in |
| Functions | Check or manage local PC folder |
| Usage | var fs = require(‘fs’);
//check if logFolder is existing. Otherwise, create this folder fs.existsSync(logFolder) || fs.mkdirSync(logFolder); |
| Package | file-stream-rotator |
| NPM Install | npm install file-stream-rotator |
| Functions | Define the log file properties like log4j, such as rotation period ‘daily‘ and log file name demo2_%DATE%.log’ |
| Usage | var FileStreamRotator = require(‘file-stream-rotator’);
… //Logger details var logFileStream = FileStreamRotator.getStream({ date_format: ‘YYYY-MM-DD’, filename: logFolder + ‘/demo2_%DATE%.log‘, frequency: ‘daily‘, verbose: false }); |
| Package | morgan |
| NPM Install | npm install morgan |
| Functions | Streaming the logging message to log file |
| Usage | var morgan = require(‘morgan’);
//Assign the logger with file stream app.use(morgan(‘combined’, {stream: logFileStream})); |
| Package | mysql |
| NPM Install | npm install mysql |
| Functions | MySQL driver in order to connect to MySQL DB |
| Usage | //Declare MySQL library
var mysql = require(‘mysql’); //Declare MySQL connection pool var pool = mysql.createPool({ host: ‘localhost’, user: ‘root’, password: ‘root’, database: ‘itblogs2’, port: 3306 }); … //Getting DB connection from connection pool, and then running SQL exports.runQuery = function(query,callback) { //Making Query pool.getConnection(function(err, connection){ connection.query( query, function(err, rows){ if(err) { throw err; }else{ console.log( query ); callback(rows); } }); connection.release(); }); }; |
| Package | http-status-codes |
| NPM Install | npm install http-status-codes |
| Functions | Provide the HTTP response status, such as:
200 – HttpStatus.OK 404 – HttpStatus.NOT_FOUND 409 – HttpStatus.CONFLICT |
| Usage | var HttpStatus = require(‘http-status-codes’);
… //response the request with HTTP status 200 – HttpStatus.OK res.send( HttpStatus.OK ); |
| Package | path |
| NPM Install | Node.js built-in |
| Functions | This package helps to manipulate the file path easily |
| Usage | var path = require(‘path’);
… app.use(express.static( path.join(__dirname, ‘/public’))); |
| Package | socket.io |
| NPM Install | npm install socket.io |
| Functions | Socket IO for server side |
| Usage | // Define socket IO
var io = require(‘socket.io’)(); … //When new client is connected io.on(‘connection’, function (socket) { console.log(‘hello… you are connected (id=’ + socket.id + ‘).’); _socket = socket;
//Receiving incoming message ‘message_reply’ socket.on(‘message_reply’, function(msg) { console.info(‘message_reply : ‘+msg); });
//When disconnect socket.on(‘disconnect’, function() { console.info(‘Socket id=’ + _socket.id + ‘ has gone.’); }); }); |
| Package | socket.io-client |
| NPM Install | npm install socket.io-client |
| Functions | Socket IO for client side, sending socket message |
| Usage | // Define client socket IO
var io = require(‘socket.io-client’); var client = io.connect(‘http://localhost:3000’); … //Receiving incoming message ‘ping_client’ client.on(‘ping_client’, function(msg) { console.info(‘Receiving ping message from server : ‘+msg);
//Send message to server client.emit(‘message_reply’, ‘Hi server, got your message’); console.info(‘Sending ack message to server’); }); |
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