Push Notifications with Angular & Express

Adding the service worker module

ng add @angular/pwa

Generating a VAPID key-pair

yarn global add web-push

web-push generate-vapid-keys --json

Subscribing to push notifications

src/app/app.component.ts

import { Component } from '@angular/core'
import { SwPush } from '@angular/service-worker'
import { PushNotificationService } from './pushNotification.service'

const VAPID_PUBLIC =
  'BNOJyTgwrEwK9lbetRcougxkRgLpPs1DX0YCfA5ZzXu4z9p_Et5EnvMja7MGfCqyFCY4FnFnJVICM4bMUcnrxWg'

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
class AppComponent {
  title = 'angular-push-notifications'

  constructor(swPush: SwPush, pushService: PushNotificationService) {
    if (swPush.isEnabled) {
      swPush
        .requestSubscription({
          serverPublicKey: VAPID_PUBLIC,
        })
        .then(subscription => {
          pushService.sendSubscriptionToTheServer(subscription).subscribe()
        })
        .catch(console.error)
    }
  }
}

src/app/pushNotification.service.ts

import { Injectable } from '@angular/core'
import { HttpClient } from '@angular/common/http'

const SERVER_URL = 'http://localhost:3000/subscription'

@Injectable()
class PushNotificationService {
  constructor(private http: HttpClient) {}

  public sendSubscriptionToTheServer(subscription: PushSubscription) {
    return this.http.post(SERVER_URL, subscription)
  }
}

Setting up a new Express project

Installing dependencies

yarn add body-parser cors express web-push

Creating an Express server

const express = require('express')
const webpush = require('web-push')
const cors = require('cors')
const bodyParser = require('body-parser')

const PUBLIC_VAPID =
  'BNOJyTgwrEwK9lbetRcougxkRgLpPs1DX0YCfA5ZzXu4z9p_Et5EnvMja7MGfCqyFCY4FnFnJVICM4bMUcnrxWg'
const PRIVATE_VAPID = '_kRzHiscHBIGftfA7IehH9EA3RvBl8SBYhXBAMz6GrI'

const fakeDatabase = []

const app = express()

app.use(cors())
app.use(bodyParser.json())

webpush.setVapidDetails('mailto:[email protected]', PUBLIC_VAPID, PRIVATE_VAPID)

app.post('/subscription', (req, res) => {
  const subscription = req.body
  fakeDatabase.push(subscription)
})

app.post('/sendNotification', (req, res) => {
  const notificationPayload = {
    notification: {
      title: 'New Notification',
      body: 'This is the body of the notification',
      icon: 'assets/icons/icon-512x512.png',
    },
  }

  const promises = []
  fakeDatabase.forEach(subscription => {
    promises.push(
      webpush.sendNotification(
        subscription,
        JSON.stringify(notificationPayload)
      )
    )
  })
  Promise.all(promises).then(() => res.sendStatus(200))
})

app.listen(3000, () => {
  console.log('Server started on port 3000')
})

References
https://malcoded.com/posts/angular-push-notifications/
https://blog.angular-university.io/angular-push-notifications/
https://medium.com/@a.adendrata/push-notifications-with-angular-6-firebase-cloud-massaging-dbfb5fbc0eeb
https://developers.google.com/web/fundamentals/push-notifications/display-a-notification

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