Building Applications With the MEAN Stack

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Nir NoyBuilding Applications With the MEAN stack

About meNir Noy

Full stack DeveloperWeb ConsultantSpeaker

Co-Organizer Of FrontEnd.IL Meetup Group

http://www.meetup.com/FrontEnd-IL

Upcoming MeetupFrontEnd.IL Meetup – Advanced Angular 2

https://www.meetup.com/FrontEnd-IL/events/233531658/

27/9/2016 – The Passage Bar, Tel AvivAngular 2 With ReduxChange Detection in Angular 2

What is MEAN?

The MEAN StackThe term MEAN stack refers to a collection of JavaScript based technologies used to develop web applications.

M E A N

Node.js

What is Node.jsA JavaScript runtime that is designed for asynchronous IO operationsVery lightweight and fastBeing used by a growing number of companies:

The Node.js ecosystemNode.js has a rapidly growing ecosystem:

Web frameworks:ExpressSocket.io

Database supportSql DatabasesNoSql Databases

Hosting and Cloud environmentsIIS, AzureHerokuJoyent

Synchronous server operations// GET api/countriespublic string Get(){

var client = WebRequest.Create("http://.../");

var response = client.GetResponse();var stream = response.GetResponseStream();var reader = new StreamReader(stream);return reader.ReadToEnd();

}Blocking I/O operation

The Cost of I/OI/O Operations are expensive.

I/O Source CPU Cycles

L1 – Cache 3

L2 – Cache 14

RAM 250

Disk 41,000,000

Network 240,000,000

Handling I/O Waiting for I/O operations to complete is one of the most common performance bottlenecks.There are several common solutions to handle it:

SynchronousPros: simple.Cons: blocking, can hold up other requests.

Fork a new processPros: efficient, not holding up other requests.Cons: does not scale, ~100 connections=~100 processes .

Handling I/O Threads:

Pros: efficient, not holding up other requests but more lightweight then executing another process

Cons: memory-expensive - ~1MB per thread, complicated, need to worry about controlling access and shared resources.

Traditional web-servers (IIS, Apache) today use an optimized thread-per-connection model that uses thread pools.

Handling I/O in Node.jsNode.js runs your code on a single thread.All I/O operations are asynchronous and Non-Blocking

Internally threads and processes are used but not explicitly exposed to your code.

When an I/O operation completes, an event is triggered and the result is passed to a callback function.

Why Node.js Lightweight and efficient

using non-blocking I/O keeps memory consumption stable by reducing the number of threads.Less context switching overhead.

Concurrencyusing non-blocking I/O keeps the main thread responsive and allowing it support tens of thousands of concurrent connections.

One Languageallows reuse of resources between the client and server.

Async server in Node.js

Node.js Event loopI/O operations are evented and external events are handled by Node’s Event loop.

Javascript functions are passed to a queue and invoked when the return value from their current I/O calls is available.

I/O Callbacks are invoked synchronously by the order they returned.

Node.js Event loop

Server

Register Callback

AsyncWorkers

DDB, FS, Network,

etc…

Request

Response

Request

ResponseRegister Callback

Node.js single thread

Node.js UsageRunning CPU intensive tasks (e.g. long running loops) on Node.js’s main thread should be avoided as it will block handling other requests to the server.

Running CPU intensive tasks can be scaled out to multiple node processes.

Node.js can run a managed cluster of multiple processes to scale out an entire application.

Node.js process architectureNode.exe

CommonJS – Module loader

JavaScript Application

Core Javascript modules for file system, network, http, etc…

Responsible for loading modules and manage dependencies. Using CommonJS’s module definition.

Multi-platform library written in C that handles all async I/O operations.

Google’s Javascript Engine.Compiles the Javascript code to native machine code.

Node Package Manager (NPM)The Node Package Manager (NPM) provides a management mechanism for modules:

Download and installVersion managementDeployment

Managing DependenciesNPM packages are managed in a file called package.jsonpackage.json schema define fields like:

name, descriptionVersionDependencies

Dependencies are being resolved during NPM install

{ "name": "app", "version": "0.0.0", "private": true, "scripts": { "start": "node ./bin/www" }, "dependencies": { "body-parser": "~1.10.2", "cookie-parser": "~1.3.3", "debug": "~2.1.1", "express": "~4.11.1", "jade": "~1.9.1", "lodash": "^3.3.1", "morgan": "~1.5.1", "serve-favicon": "~2.2.0" }}

A look at Package.json

Managing DependenciesNPM packages are installed inside a folder named node_modules

The folder is created inside the path where the “npm install …” was executed.

When a npm module is required node will look it up inside the node_modules folder of the current path.

If the module is not found it is recursively searched up the folder tree.

ExpressJS

Introduction to ExpressJSNode.js http module provides bare-bones HTTP server functionalityBuilding a modern web application server would require implementing many common features such as:

RoutingSession ManagementCookies & Requests ParsersRequest Logging

Introduction to ExpressJSExpressJS is a web application framework inspired by Sinatra.Express middleware provides an expendable Http pipeline on top of Node.js's httpServerAn Express application is essentially a series of middleware callsA middleware is simply a function with access to the request object, response object and a callback to next middleware in line.

ExpressJS is available through npm$ npm install express --save

ExpressJS provides a generator tool to quickly create an application skeleton.

$ npm install express-generator –g

//run $ express -h

ExpressJS Installation

Routing is one of the pillars of ExpressJSTo create a route use the app.verb convention

// respond with "Hello World!" on the homepageapp.get('/', function (req, res) { res.send('Hello World!');})

// accept POST request on the homepageapp.post('/', function (req, res) { res.send('Got a POST request');})

// accept PUT request at /userapp.put('/user', function (req, res) { res.send('Got a PUT request at /user');})

Routing

A router is an isolated instance of middlewares and routes.

The router can have middleware and http VERB routes added just like an application.

var router = express.Router([options]);

router.get('/events', function(req, res, next) { // .. some logic here .. like any other middleware // ..});

Routers

Routing and ParametersExpress support parameters as part of the URI

Declare a parameter in the URI by using a “:” in front of itAccess query-string parameters using req.query Use regular expressions

Express

MongoDB

MongoDBMongoDB is a document database

Stores BSON (Binary JSON) documentsCan search based on data stored in the BSON document Easily return results in JSON

MongoDB is one of the Most popular databases in the Node.js eco-system

ODM with Mongoose Object Data Model (ODM) tools allow you to create an object model in your applications that map to documentsMongoose allows you to create schemas for objects and bind them to MongoDB documents

Express With Mongo

Angular 2

Angular 2 OverviewAngular 2 is a new framework for building javascript applications.

Open source (MIT license), written by Google

Fast and smallModern approach, tools and practicesDesigned for modern architectures and challenges

Setting up an Angular 2 Project

Angular 2 projects almost always use a buildHave many dependenciesRequire a lot of configuration

There are several approaches to setting up Angular 2 projects:

ManuallyUsing a Yeoman generatorUsing the Angular 2 CLIUsing an Angular 2 seed projecthttps://github.com/angular/angular2-seed

Angular 2 Development Environment

SystemJS / Webpack• Javascript module bundler

Typescript + ES 2015• A Javascript Superset• Official Language of Angular 2

npm• Node.js package manager.

Node.js• Server Javascript runtime.• Used For Webservers and

scripting tools

The Build ProcessWritten code and executed code are different

Any build system can be used (webpack, SystemJS, gulp, etc.)

Develop

•Write code using TypeScript, Less, etc.

•Transpile•Lint•Test•Prerender

Execute

• JavaScript in the browser

• Natively on other target platforms

Basic Angular Project Structure/package.json the Node project file/tsconfig.json the TypeScript project file/typings.json the Typings manifest file

/node_modules the Node modules folder/typings the Typings folder/src the source code folder

From MVC to ComponentsComponents are a higher-level abstraction than MVC

MV* Frameworks focuses on controllers

Angular 2 focuses on components

Component classes implement logicControllers and views are metadata

Components(Angular 2)

Views and Controllers(MV* frameworks)

Angular2 ArchitectureAn Angular2 application is a tree of components.

Root Component

Child Compoment-A

grandChild Compoment-A1

Child Compoment-B

grandChild Compoment-B

Angular2 ArchitectureComponents Communicate in a unidirectional data flow

Root Component

Child Compoment-A

Child Compoment-B

Angular2 ArchitectureData is Flowing downwards.

Root Component

Child Compoment-A

Child Compoment-B

Data Binding

Angular2 ArchitectureEvents are Flowing upwards.

Root Component

Child Compoment-A

Child Compoment-B

Data BindingEv

Angular2 ArchitectureEach Component Can consume injectable Services.

Component

Service A

Service B

Service C

Dependency

injection

Dependency injection

Angular2 ArchitectureComponents, Services, Directives and Pipes are all defined inside Angular Modules

Module A

Component A Pipe A Service A Directive A

Module B

Component B Service BImports

Hello Angular 2

Scaffolding

YeomanYeoman is Node.js based tool, that helps kickstart new projects.With a set of plugins called “generators” you can scaffold complete projects or useful parts.“Generators” promote a robust and opinionated tehcnology stack based on common standards and best practices.

Yeoman MEAN GeneratorsThere Several Common MEAN generators:

angular-fullstack – Most updated MEAN generator with angular 1.xMeanjs – Generator by of the creators of MEANhttps://github.com/datatypevoid/vulgar - generator with Angular 2 (updated to Angular 2 RC1)

Thank YouNir Noy | @noynir | nirn@sela.co.il

Building Applications With the MEAN Stack

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