JS on Backend
Express & Mongo
Created by Maksym Tarasenko
Agenda
- REST
- Express.js
- MongoDB
- Mongoose
REST
Representational State Transfer
CRUD
Express.js – a node.js web framework
- Based on Connect
- De facto standard framework of node web apps
- Minimalistic
- Supports a variety of middleware
Basics
- Middleware concept
- Configuration of express
- Request
- Response
Middleware
Middleware concept
var express = require('express');
var app = express();
app.use(bodyParser.json());
app.use(function (req, res, next) {
console.log('Time:', Date.now());
next();
});
app.get('/user', function(req, res) {
res.send('hello user');
});
app.listen(3000, function () {
console.log('Example app listening on port 3000!');
});
Routing
- Respond to HTTP requests with a callback
- Supports variable placement in routes
- Easy to serve JSON
- Routing filter types
Routing
app.get('/', function (req, res) {});
app.post('/:id', function (req, res) {});
var express = require('express');
var router = express.Router();
router.put(/\/abc|\/xyz/, function (req, res) {}});
router.delete(['/', '/:id'], function (req, res) {});
Templating
app.set('view engine', 'ejs');
app.locals.title = 'My App';
app.get('/', function (req, res) {
res.locals.someText = 'test';
res.render('test', { message: 'Hello there!'});;
});
MongoDB Basics
- DataBase
- Collection
- Document
- Field
Create
db.unicorns
.insert({
name: 'Aurora',
dob: new Date(1992,2,13,7,47),
loves: ['carrot','papaya'],
weight: 600,
gender: 'm',
vampires: 63
});
Find
db.unicorns.find({gender: 'm', weight: {$gt: 700}})
db.unicorns.find({gender: {$ne: 'f'}, weight: {$gte: 701}})
//$lt, $lte, $gt, $gte, $ne, $or
db.unicorns.find({
gender: 'f',
$or: [
{loves: 'apple'},
{loves: 'orange'},
{weight: {$lt: 500}}
]})
//Projection
db.unicorns.find({vampires: {$exists: false}}, { name:1, _id: 0})
.skip(2)
.limit(5)
.sort({name:1})
update
db.unicorns.insert({})
db.unicorns.insert([{}, {}])
db.unicorns.update(
{gender: 'm'},// selector
{
$set: {loves: "grape"},
$currentDate: {dob: true}
},//update
{
multi: true,
upsert: true
}
)
// remove all
db.unicorns.remove({})
// remove match condition
db.unicorns.remove({type: "food"})
// remove match condition only one
db.unicorns.remove({type: "food"}, 1)
ORM-way: Mongoose
- SCHEMA
- MODEL
- Fields types
Connection
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');
var db = mongoose.connection;
mongoose.Promise = require('q').Promise;
db.on('error', function(err) {
console.error('connection error:', err));
});
db.once('open', function (callback) {
console.log('connected');
});
MODEL
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var RolesSchema = new Schema({
role: {
type: String,
required: true
},
date: {type: Date, default: Date.now},
members: [{ type: String }]
}, {collection: 'roles'});
module.exports = mongoose.model('Roles', RolesSchema);
MODEL
RolesSchema.methods.findAllMembersRoles = function () {
return this.model('Roles').find({members: this.members});
}
RolesSchema.statics.findByName = function (name) {
return this.find({role: new RegExp(name, 'i')});
}
RolesSchema.virtual('membersAll')
.get(function () {
return this.members.join(',');
})
.set(function (members) {
var membersArray = members.split(',');
this.members = membersArray;
});
Work with model: Save
var newModel = new model({
role: 'dev',
members: ['user1', 'user3']
});
newModel.save(function (err) {
if (err) return handleError(err);
saved!
});
newModel.save()
.then()
.catch()
Work with model: Find
model.find({role: 'dev'})
.skip(skip)
.limit(limit)
model.findById(id)
.then(function (modelInstance) {
var updatedInstance = _.extend(modelInstance, req.body);
return updatedInstance.save();
})
Work with model: Find
model.remove({role: 'dev'})
model.update({
role: 'dev'
}, {
$set: {members: ['user2']}
})