Angular (web framework)

Angular is a web framework by Google which allows you to create progressive web apps (PWAs) which are single page applications (SPA).
It can also be used to create native mobile or desktop apps.
Note that this is a front-end framework only. You will need to pair it with a back-end framework to get stateful functionality.

This page is about Angular, also known as Angular 2. For AngularJS, the predecessor to Angular, see https://angularjs.org/.

Getting Started

See Angular Guide Setup Local.

• Install NodeJS and npm
• Install the Angular CLI: npm install -g @angular/cli

Creating a project

ng new <project-name>

ng serve --open

Usage

Components

ng generate component <name>

Components are the building blocks of Angular.
Each component consists of a HTML block and an associated JS class.

Services

Services are singleton classes which can be accessed from any component.

ng generate service <name>

To access a service from a component, add a reference to the service as a parameter to the constructor of your component.

Routing

ng generate module app-routing --flat --module=app

Expand

Route Module Example

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { HeroesComponent } from './heroes/heroes.component';

const routes: Routes = [
  { path: 'heroes', component: HeroesComponent }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

Deployment

See Angular Guide Deployment

The basic idea is to do the following:

1. Create a production build:

   ng build --prod

2. Copy the dist folder to the server.
3. Redirect missing files to index.html.

Apache

Place the following in the apache config for your site or in an .htaccess file:

Expand

Rewrite Rules

RewriteEngine On
# If an existing asset or directory is requested go to it as it is
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -f [OR]
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -d
RewriteRule ^ - [L]

# If the requested resource doesn't exist, use index.html
RewriteRule ^ /index.html

Express

How to setup an Express server to host your Angular web application:

Expand

Route

First setup CSRF Protection:

this.csrfProtection = csurf({cookie: true});
this.app.use(this.csrfProtection);
this.app.all(
  '*',
  (req: Request, res: Response, next: NextFunction): void => {
    res.cookie('XSRF-TOKEN', req.csrfToken());
    next();
  }
);

Then setup your routes to serve your frontend:

if (CONFIG.app.useProxy) {
  const myProxy = httpProxy.createProxyServer({ws: true});
  console.log(`Proxying to ${CONFIG.app.appProxy}`);
  router.all('/*', (req: Request, res: Response, next: NextFunction) => {
    myProxy.web(
      req,
      res,
      {target: req.protocol + '://' + CONFIG.app.appProxy}
    );
  });
} else {
  router.all('/*', express.static(CONFIG.app.appFolder));
  router.all('/*', (req: Request, res: Response, next: NextFunction) => {
    res.status(200).sendFile('index.html', {root: CONFIG.app.appFolder});
  });
}

If you are proxying for development, you will also need to proxy websockets:

server.on(
  'upgrade',
  (request: http.IncomingMessage, socket: net.Socket, head: Buffer) => {
    const pathname = url.parse(request.url).pathname;

    if (pathname === '/backend') {
      this.wss.handleUpgrade(request, socket, head, ws => {
        this.wss.emit('connection', ws);
      });
    } else if (CONFIG.app.useProxy) {
      console.log('proxying websocket');
      myProxy.ws(request, socket, head, {
        target: 'ws://' + CONFIG.app.appProxy,
      });
    } else {
      socket.destroy();
    }
  }
);

Libraries

Some interesting libraries for Angular

• Angular Components
  • Angular Material (website)

Advanced Usage

CSRF/XSRF

See http#security-xsrf-protection

By default, the HttpClientModule will automatically reflect the XSRF-TOKEN cookie as X-XSRF-TOKEN if the following conditions are met:

• XSRF-TOKEN is a cookie under / with HttpOnly set to false.
• The outgoing request is not a GET or HEAD request.
• The outgoing request path is a relative path of form api/endpoint or //example.com/api/endpoint.

You can also set the name of the cookie and name of the header to something else if you prefer.

Resources

• Official Angular Tutorial
  • Teaches you to build a simple Tour of Heros app in less than 1 hour.
• Official Angular Cheat Sheet