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NodeJS
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REQUIRED TOOLS Browser: Chrome NodeJS (current) API tester: Postman (as plugin for Chrome) IDE: Jetbrains Webstorm / Jetbrains IntelliJ IDEA MongoDB Community Server Robo3T – MongoDB GUI Client
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NodeJS Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.
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Where to host NodeJS app ?
Amazon Web Services – Free Tier Google cloud platform – free trial Microsoft Azure – free trial Private VPS / Hosting
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CREATING NODEJS PROJECT
Manually npm init Webstorm: File->New->Project
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ADDING PACKAGES New node_modules directory created Package.json: TIP:
npm i –S npm i –S { "name": "my-first-app", "version": "1.0.0", "description": "Some description", "main": "index.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "author": "Krzysztof Bzowski", "license": "ISC", "dependencies": { "express": "^4.16.0" } TIP: npm install Will install all mising dependencies
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ADDING PACKAGES VIA WEBSTORM
File -> Settings -> Languages & Frameworks -> Node.js and NPM
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PREPARATIONS – SIMPLE VERSION!
Directory structure Project root node_modules src public Api Files: server.js api/index.js Starting script: package.json { […] "scripts": { "test": "echo \"Error: no test specified\" && exit 1", "start": "node dist\server.js" }, […] }
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PREPARATIONS – CODING ASSISTANCE
File -> Settings -> Languages & Frameworks | Node.js and npm
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BABEL The compiler for writing next generation JavaScript
npm i -D babel-cli npm i -D babel-preset-env Webstorm: Files -> Settings -> Tools -> File Watchers
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RUNNING - WEBSTORM Run -> Edit configuration Start Debug
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Server Config Create file config.js EDITOR TRANSPILED BY BABEL
const env = process.env; export const nodeEnv = env.Node_ENV || 'development' export default { port: env.PORT || 8080 }; 'use strict'; Object.defineProperty(exports, "__esModule", { value: true }); var env = process.env; var nodeEnv = exports.nodeEnv = env.Node_ENV || 'development'; exports.default = { port: env.PORT || 8080 }; //# sourceMappingURL=config.js.map
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Server – server.js Local module Core module Event emiter object
import config, {nodeEnv} from "./config"; import http from 'http' Core module Event emiter object const server = http.createServer(); server.listen(8080); server.on('request', (req, res) => { // Handle request }); Event callback with parameters: Request Response
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Server – server.js import config, {nodeEnv} from "./config"; import http from 'http' const server = http.createServer(); server.listen(8080); server.on('request', (req, res) => { // Handle request res.write('Hello HTTP!\n'); res.end(); });
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Testing - Postman Request type Bookmark Send request RESPONSE
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Express.js Core HTTP module is powerfull but with growing application it will be very hard to handle all requests. This is why Express framework (and many more) were created import config, {nodeEnv} from "./config"; import express from 'express' const server= express(); // Routing server.get('/', (req, res) => { res.send('Hello express'); }); server.listen(config.port, () => { console.log('Express listening on port ', config.port); });
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Express.js - routing import config, {nodeEnv} from "./config"; import express from 'express' const server= express(); // Routing server.get('/', (req, res) => { res.send('Hello express'); }); server.get('/about', (req, res) => { res.send('This is Express App on ' + config.port); }); server.listen(config.port, () => { console.log('Express listening on port ', config.port); });
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Express.js – return file
import fs from "fs"; […] server.get('/about.html', (req, res) => { fs.readFile('./public/about.html', (err, data) => { res.send(data.toString()); }) }); ./public/about.html: <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>About</title> </head> <body> <h1>About</h1> <p>This is Express App!</p> </body> </html>
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Express.js – menage static files
No fs module No routing ./server.js: […] server.use(express.static('public’));
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Express.js - Routing ./api/index.js: ./server.js:
import express from 'express' const router = express.Router(); router.get('/', (req, res) => { res.send({data: []}) }); export default router; ./server.js: import config, {nodeEnv} from "./config"; import apiRouter from './api' import express from 'express' const server= express(); server.use('/api', apiRouter); server.use(express.static('public')); server.listen(config.port, () => { console.log('Express listening on port ', config.port); });
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REST Representational state transfer (REST) or RESTful web services
GET == Read POST == Create PUT == Update PATCH == Modify (partially) DELETE = Remove
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REST HTTP Methods POST Create GET Read PUT Update/Replace PATCH
HTTP Verb CRUD Entire Collection (e.g. /collection) Specific Item (e.g. /collection/{id}) POST Create 201 (Created), 'Location' header with link to /collection/{id} containing new ID. 404 (Not Found), 409 (Conflict) if resource already exists.. GET Read 200 (OK), list of customers. Use pagination, sorting and filtering to navigate big lists. 200 (OK), single customer. 404 (Not Found), if ID not found or invalid. PUT Update/Replace 405 (Method Not Allowed), unless you want to update/replace every resource in the entire collection. 200 (OK) or 204 (No Content). 404 (Not Found), if ID not found or invalid. PATCH Update/Modify 405 (Method Not Allowed), unless you want to modify the collection itself. DELETE Delete 405 (Method Not Allowed), unless you want to delete the whole collection—not often desirable. 200 (OK). 404 (Not Found), if ID not found or invalid.
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Handling errors ./api/index.js: […]
router.get('/user/:id', (req, res) => { if(req.params.id == 1){ res.send({ id: 1, name: 'Krzysztof' }) } else { res.status(404).send({ error: 'user not found' }) } });
![Handling errors ./api/index.js: […]](http://slideplayer.com./slide/12736396/76/images/23/Handling+errors+.%2Fapi%2Findex.js%3A+%5B%E2%80%A6%5D.jpg "router.get( /user/:id , (req, res) => { if(req.params.id == 1){ res.send({ id: 1, name: Krzysztof }) } else { res.status(404).send({ error: user not found }) } });")
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POST ./server.js: ./api/index.js: import bodyParser from 'body-parser’
[…] const server = express(); server.use(bodyParser.json()); ./api/index.js: router.post('/user', (req, res) => { console.log(req.body); res.send(req.body); console.log(`Trying to create ${req.body.name} user.`); });
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POST REQUEST BODY RESPONSE BODY
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MongoDB Running server "c:\Program Files\MongoDB\Server\3.4\bin\mongod.exe" --dbpath=e:\MongoDB\ TIP: Make an desktop shortcut with this command! Database storage Some convenient path with write access (i.e. home directory)
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MongoDB
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MongoDB Create database
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MongoDB Create collection with example data { "name" : "Krzysztof",
"role" : "teacher" }
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MongoDB Browse data
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MongoDB – Access from NodeJS
npm i -S mongodb ./config.js: const env = process.env; export const nodeEnv = env.Node_ENV || 'development'; export default { mongoUri: 'mongodb://localhost:27017/ie2017NS', port: env.PORT || 8080 };
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MongoDB – Access from NodeJS
import {MongoClient, ObjectID} from 'mongodb' import assert from 'assert' import config from '../config' let mdb; MongoClient.connect(config.mongoUri, (err, db) => { assert.equal(null, err); mdb = db; }); const router = express.Router(); router.get('/user', (req, res) => { let users = {}; mdb.collection('User').find({}).toArray(function(err, docs) { docs.forEach((doc) => { users[doc._id] = doc; }); res.send(users); }); });
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MongoDB – filter data router.get('/user/:userId', (req, res) => { let users = {}; mdb.collection('User') findOne({_id : ObjectID(req.params.userId)}) then(user => res.send(user)) catch(console.error) });
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MongoDB – Inserting documents
router.post('/user', (req, res) => { const name = req.body.name; const role = req.body.role; mdb.collection('User').insertOne({ name, role }).then(result => { res.send(result.insertedId) }) });
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MongoDB – Update document
router.put('/user/:userId', (req, res) => { let uid = req.params.userId; const role = req.body.role; mdb.collection('User').findOneAndUpdate( {_id: ObjectID(uid)}, { $set: { role } }, {new: true} ).then(result => { if (result.ok === 1) { res.send(''); } else { res.status(404).send({'Error': 'User not found'}) } }).catch(err => { let g = 3; }) });
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MongoDB – Delete document
router.delete('/user/:userId', (req, res) => { let uid = req.params.userId; mdb.collection('User').deleteOne( {_id: ObjectID(uid)} ).then(result => { if(result.deletedCount === 0){ res.status(404).send({'Error': 'User not found'}) } else { res.send(''); } }) });
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