caching - Angular Service Worker SwUpdate.available not triggered

Question

I'm having a hard time integrating angulars service worker into my application. I followed the guide and it works so far. I can create a shortcut on my homescreen and launch into my app. The problem is that my app somehow doesn't update. If I change the name of a button, build the app and put it onto my server the app still shows the old version until I hit F5 (restarting the app doesn't help either).

I tried to put the following code into my ngOnInot of my app but it didn't help

ngOnInit() {
if (this._SwUpdate.isEnabled) {

  setInterval( () => {
    this._SwUpdate.checkForUpdate().then(() => console.log('checking for updates'));
  }, this.updateInterval);

  this._SwUpdate.available.subscribe(() => {

    console.log('update found');

    this._SwUpdate.activateUpdate().then(() => {
      console.log('updated');
      window.location.reload();
    });

  });

}

}

The app is running on my apache2 linux machine. Is my apache caching something or why doesn't my app realize that there is a new version?

Thanks in advance for your help :)

Edit:

My ngsw-config.json

{
  "index": "/index.html",
  "assetGroups": [{
    "name": "roomPlan",
    "installMode": "prefetch",
    "resources": {
      "files": [
        "/index.html",
        "/*.css",
        "/*.js"
      ]
    }
  }, {
    "name": "assets",
    "installMode": "lazy",
    "updateMode": "prefetch",
    "resources": {
      "files": [
        "/assets/**"
      ]
    }
  }]
}

Edit 2:

It works if I run the app local using "http-server" but when I copy the files over to my apache it doesn't detect the update. In the networking tab I can see that the interval works, the app gets a new "ngsw.json" from the server every 3 seconds. If I update my app I can see that there are new hash values inside of the response for "ngsw.json". After that the browser loads the new "index.html" and "main.***.js" from my server but the app doesn't apply the new version. According to my code it should say "update found" but nothing happens.

question from:https://stackoverflow.com/questions/50968902/angular-service-worker-swupdate-available-not-triggered

Answer 1

You will probably need to tell the service worker to check the server for updates, I usually use a service for this:

export class UpdateService {

  constructor(public updates: SwUpdate) {
    if (updates.isEnabled) {
      interval(6 * 60 * 60).subscribe(() => updates.checkForUpdate()
        .then(() => console.log('checking for updates')));
    }
  }

  public checkForUpdates(): void {
    this.updates.available.subscribe(event => this.promptUser());
  }

  private promptUser(): void {
    console.log('updating to new version');
    this.updates.activateUpdate().then(() => document.location.reload()); 
  }

In your app-component.ts:

  constructor(private sw: UpdateService) {
    // check the service worker for updates
    this.sw.checkForUpdates();
  }

---

For whatever reason, Angular sometimes does not register the service worker properly. So you can modify `main.ts` :

Replace:

platformBrowserDynamic().bootstrapModule(AppModule);

With:

platformBrowserDynamic().bootstrapModule(AppModule).then(() => {
  if ('serviceWorker' in navigator && environment.production) {
    navigator.serviceWorker.register('ngsw-worker.js');
  }
}).catch(err => console.log(err));