Cours NoSQL

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# Cours NoSQL: Node.js

## Haïkel Guémar - haikel.guemar@gmail.com

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# Introduction

![logo](img/nodejs-logo.png)

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## Installation

http://nodejs.org/download

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## Tester son installation

```bash
$ node
> console.log('hello world!')
```

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## Synchrone

```javascript
var doc = db.things.findOne()

printjson(doc)
```
<img src="img/threading_java.png" width="60%" />

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## Asynchrone

```javascript
var MongoClient = require('mongodb').MongoClient;

MongoClient.connect('mongodb://127.0.0.1/test', function(err, db) {
  if (err) throw err; // gestion d'erreur

db.collection('things').findOne({}, function(err, doc) {
    console.dir(doc);
    db.close(doc); 
  });

console.dir('Found a document'); 
});
```

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## Asynchrone

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## Hello World avec Node.js

```javascript
var http = require('http');

var server = http.createServer(function(request, response) {
  response.writeHead(200, {"ContentType": "text/plain"});
  response.end("Hello World!");
});

server.listen(8000)  
// Cf. http://localhost:8000
```

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## Node Packages Manager (NPM)

```bash
$ npm install express consolidate pug mongodb
```

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## Packages.json

```javascript
{
"name": "first_app",
"version": "0.0.1",
"description": "first node app",
"main": "app.js",
"dependencies": {
"consolidate": "~0.11.0",
"express": "~4.12.1",
"mongodb": "~1.4.32"
},
"author": "Bob Leponge",
"license": "BSD"
}
```

```bash
$ npm install
```

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## Hello world avec Express

```javascript
var express = require('express');
var app = express();

app.get('/', function(req, res) {
  res.send("Hello World!");
});

app.listen(8000);
console.log("Express server started on 8000");
```

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## Express et les middlewares

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# Vues et Templates

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## Pug

* Pug est un moteur de template
* Consolidate est une bibliothèque facilitant l'intégration des moteurs de templates

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## Pug (1/2)

Dans un fichier views/hello.html
```javascript
doctype html
html(lang="en")
  head
    title Hello World!
  body
    h1 Hello #{name}
```

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## Pug (2/2)

```javascript
var express = require('express');
var cons = require('consolidate');
var app = express();

app.engine('html', cons.pug);
app.set('view engine', 'html');
app.set('views',  __dirname +  '/views')

app.get('/', function(req, res) {
  res.render("hello",  {"name": "pug"});
});

app.get('*', function(req, res) {
  res.send("Page not found", 404);
});

app.listen(8000);
console.log("Express server started on 8000");
```

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# Appliquons !

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## Driver mongodb recommandé

* Le driver officiel
https://www.npmjs.com/package/mongodb

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## Remplissons la base

```bash
$ mongo
> use cours
> db.mongoexpress.insert({"name": "MongoDB"})
```

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## Les bases

```javascript
var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://localhost:27017';
var dbName = 'mongoexpress';

MongoClient.connect(url, function(err, client) {
  console.log("Connection succeeded");
  var db = client.db(dbName);
  /* On fait des choses */
  client.close();
}

```

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## Application (1/2)

```javascript
var express = require('express');
var cons = require('consolidate');
var app = express();
var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://localhost:27017';
var dbName = 'cours2019';

app.engine('html', cons.pug);
app.set('view engine', 'html');
app.set('views',  __dirname +  '/views');

app.get('/', function(req, res) {
  app.db.collection('mongoexpress').findOne({}, function(err, doc) {
      res.render("hello",  doc);
  });
});

app.get('*', function(req, res) {
  res.send("Page not found", 404);
});
```

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## Application (2/2)

```javascript
MongoClient.connect(url, function(err, client) {
  app.client = client;
  app.db = client.db(dbName);
  app.listen(8000);
  console.log("Express server started on 8000");
});
```

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# Récupérer des paramètres avec GET

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## Gérer les requêtes GET avec Express

Supposons que l'on a une url
http://localhost:8000/bob?job=firefighter&age=27

* paramètre url: bob
* paramètres query: job => firefighter, age => 27

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## Le template

hello.html

```javascript
doctype html
html(lang="en")
  head
    title Hello World!
  body
    h1 Hello #{name} here are your GET variables
  ul
    li #{job}
    li #{age} years
```

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##  le code

```javascript
var express = require('express');
var cons = require('consolidate');
var app = express();

app.engine('html', cons.pug);
app.set('view engine', 'html');
app.set('views',  __dirname +  '/views')

app.get('/:name', function(req, res, next) {
  var name = req.params.name
  var job = req.query.job;
  var age = req.query.age;
  res.render("hello", {'name': name, 'job': job, 'age': age});
});

app.get('*', function(req, res) {
  res.send("Page not found", 404);
});

app.listen(8000);
console.log("Express server started on 8000");
```

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# Récupérer des paramètres avec GET

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## Body-parser

```bash
$ npm install --save body-parser
```

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## Le template

fruit_picker.html
```javascript
doctype html
html(lang="en")
  head
    title Fruit Picker
  body
    form(action='/fruit_picker', method='POST')
      p Quel est votre fruit préféré ?
      each val in fruits
        - var inputValue = val
        p
          input(type="radio", name="fruit", value=inputValue)
          | #{val}
      input(type="submit", value="submit")
```
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## Gérer les requêtes POST avec Express

```javascript
var express = require('express');
var cons = require('consolidate');
var bodyParser = require('body-parser');
var app = express();
app.engine('html', cons.pug);
app.set('view engine', 'html');
app.set('views',  __dirname +  '/views')
app.use(bodyParser())

app.get('/', function(req, res, next) {
  res.render("fruit_picker", {'fruits': ['pomme', 'poire', 'pêche', 'banane']});
});

app.post('/fruit_picker', function(req, res, next) {
  var favorite = req.body.fruit;
  if (typeof favorite == 'undefined') {
    next(Error('Please choose a fruit'));
  } else {
    res.send("Ton fruit préféré est " + favorite);
  }
});

app.listen(8000);
console.log("Express server started on 8000");
```
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# TD

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## Code moi un blog

1. comment modéliseriez-vous la base de données avec un SGBDR
2. comment le feriez-vous avec MongoDB ?

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## Avec MongoDB

```javascript
posts:

{ 'title': 'cours nosql',
  'body': '...',
  'author': '...',
  'date': '...',
  'comments': [{'name': 'Joe', 'email': 'joe@doe.com', 'comment': '...'}, ... ],
  'tags': ['cours', 'nosql', ...]
}

authors:
{_id: '...', 'password': '...'}
  
```

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# Q/A