MongoDB

1

MongoDB?

MongoDB (от англ. humongous — огромный) — документоориентированная система управления базами данных (СУБД) с открытым исходным кодом, не требующая описания схемы таблиц. Написана на языке C++.

Why MongoDB?

Ура! Долой проектирование

Subdocuments

Or not?

Нормализация

vs

Денормализация

Нормализация

Денормализация

JOINS?

JS everywhere!

ObjectID

• a 4-byte value representing the seconds since the Unix epoch,
• a 3-byte machine identifier,
• a 2-byte process id, and
• a 3-byte counter, starting with a random value.

507f191e810c19729de860ea

Приходится создавать дополнительные id

_id, id, id2, articleId

Для чего такие сложности?

Совет

Mongoose.js

2

Schema

2

const schema = new Schema({
  name:    String,
  binary:  Buffer,
  living:  Boolean,
  updated: { type: Date, default: Date.now },
  age:     { type: Number, min: 18, max: 65 },
  mixed:   Schema.Types.Mixed,
  _someId: Schema.Types.ObjectId,
  array:      [],
  ofString:   [String],
  ofNumber:   [Number],
  ofDates:    [Date],
  ofBuffer:   [Buffer],
  ofBoolean:  [Boolean],
  ofMixed:    [Schema.Types.Mixed],
  ofObjectId: [Schema.Types.ObjectId],
  nested: {
    stuff: { type: String, lowercase: true, trim: true }
  }
})

Query

2

Person.
  find({
    occupation: /host/,
    'name.last': 'Ghost',
    age: { $gt: 17, $lt: 66 },
    likes: { $in: ['vaporizing', 'talking'] }
  }).
  limit(10).
  sort({ occupation: -1 }).
  select({ name: 1, occupation: 1 });

Cursor

2

const cursor = Pet
  .find({ type: 'cat' })
  .cursor();

cursor.on('data', function(doc) {
  // Called once for every document
});
cursor.on('close', function() {
  // Called when done
});

Hooks

2

schema.pre('save', function(next) {
  if (!this.isModified('password')) return next();
  this.password = hashPassword(this.password);

  next();
});


schema.pre('validation', function(next) {
  // do stuff
  next();
});

Populate

2

Story
.find(...)
.populate({
  path: 'fans',
  match: { age: { $gte: 21 }},
  select: 'name',
  options: { limit: 5 }
})

Express.js

3

Hello World

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

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

app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

3

Hello World

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

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

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

app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

3

Request

req.app
req.baseUrl
req.body
req.cookies
req.fresh
req.hostname
req.ip
req.ips
req.method
req.originalUrl

3

req.params
req.path
req.protocol
req.query
req.route
req.secure
req.signedCookies
req.stale
req.subdomains
req.xhr

Response

res.download()	Prompt a file to be downloaded.
res.end()	End the response process.
res.json()	Send a JSON response.
res.jsonp()	Send a JSON response with JSONP support.
res.redirect()	Redirect a request.
res.render()	Render a view template.
res.send()	Send a response of various types.
res.sendFile()	Send a file as an octet stream.
res.sendStatus() Set the response status code and send its string representation as the response body.

3

Middlewares

const myLogger = (req, res, next) => {
  console.log('Log something');
  next();
};

const myBadLogger = (req, res, next) => {
  console.log('Do domething');
};

3

Middlewares

const requestTime = (req, res, next) => {
  req.requestTime = Date.now();
  next();
};

const isAdmin = (req, res, next) => {
  if (req.user.role !== 'admin') {
  	next('no access');
  }
  console.log('Do domething');
};

3

Catch-middleware

const isAdmin = (req, res, next) => {
  if (req.user.role !== 'admin') {
    return next('no access');
  }
  console.log('Do domething');
};

const catchErrors = (err, req, res, next) => {
  res.json({err});
};

3

How to use

app.use(requestTime);
app.use(myLogger);

app.get('/', function (req, res) {
  ...
  
  responseText += 
       'Generate time: ' + 
       (Date.now() - req.requestTime) + 'ms';

  res.send(responseText);
});

app.listen(3000);

3

Static

var options = {
  dotfiles: 'ignore',
  etag: false,
  extensions: ['htm', 'html'],
  index: false,
  maxAge: '1d',
  redirect: false,
  setHeaders: function (res, path, stat) {
    res.set('x-timestamp', Date.now());
  }
}

app.use('/assets', express.static('public', options));

3

Cookies

$ npm install cookie-parser

var express = require('express');
var app = express();
var cookieParser = require('cookie-parser');

// load the cookie-parsing middleware
app.use(cookieParser());

3

Nested

app.use('/some1', mw1);

app.use('/some2', mw1, mw2, mw3);

app.use('/some3', [mw1, mw2, mw3]);

app.use('/some4', [mw1, 
                   [mw21, mw22, mw22], 
                   mw3], mw4);

3

Routes

app.get('/hello', function (req, res) {
  res.send('hello world')
})

app.get('/ab?cd', ... );

app.get('/ab+cd', ... );

app.get('/ab(cd)?e', ... );

app.get(/.*fly$/, ...);

app.get('/users/:userId/books/:bookId', function (req, res) {
  res.send(req.params)
})

3

Router

// birdRoutes.js
const router = express.Router();

// middleware that is specific to this router
router.use(function timeLog(req, res, next) {
  console.log('Time: ', Date.now());
  next();
});

router.get('/', function(req, res) {
  res.send('Birds home page');
});


// index.js
import birdRoutes from './birdRoutes'
...
app.use('/birds', birdRoutes);

3

Sub apps

var express = require('express');

var app = express(); // the main app
var admin = express(); // the sub app

admin.get('/', function (req, res) {
  console.log(admin.mountpath); // /admin
  res.send('Admin Homepage');
});

app.use('/admin', admin); // mount the sub app

3

NPM

• express
• express-async-router
• express-graphql
• express-jwt
• express-ws
• express-xml-bodyparser
• express-winston

3

RESTful JSON API

4

REST

4

Ограничения

4

• Отсутствие состояния
• Единообразие интерфейса

CRUD Routes

GET /users
GET /users/:id
POST /users
PUT /users/:id
DELETE /users/:id

4

Routes

GET /users/:id/skills

GET /users/:id/pets
POST /users/:id/pets
DELETE /users/:id/pets

4

Types

GET /users
GET /users.xml
GET /users.json
GET /users.yml

4

Status Codes

4