Web Support

[Levi-Lesches]

[!note] This is a work in progress

Adds web support. The plan is as follows, taken from https://github.com/MaikuB/flutter_local_notifications/issues/481#issuecomment-2473307972:

• [ ] Whatever notification details the NotificationOptions object supports
• [x] cancel(id) by using ServiceWorkerRegistration.getNotifications() to get the notification in question, then calling Notification.cancel()
• [x] cancelAll() by calling Notification.cancel() for all the notifications returned by ServiceWorkerRegistration.getNotifications()
• [x] getActiveNotifications() by returning the result of ServiceWorkerRegistration.getNotifications()
• [ ] getNotificationAppLaunchDetails by having the service worker pass the initial event to the new window
• [ ] pendingNotificationRequest could return an empty list
• [ ] periodicallyShow, and periodicallyShowWithDuration would not be supported. They could be safely modified to return Future<bool> to see whether they succeeded.
• [x] And of course, show() would be supported by either creating a Notification object or using ServiceWorkerRegistration.showNotification()

Of course, getNotificationAppLaunchDetails and setting any handlers would require the ability to customize the service worker. That appears to be blocked on flutter/flutter#145828, but after reading flutter/flutter#156910, it seems that today's service worker is not technically needed and can be replaced. While we wait for an official mechanism to do so, there is a way to do so today:

let flutter_sw = await navigator.serviceWorker.getRegistration();
if (flutter_sw != null) flutter_sw.unregister();
let plugin_sw = await navigator.serviceWorker.register("/flutter_local_notifications_sw.js");

Where our custom service worker can start off as simple as

function _handleNotif(event) {
  console.log(`Clicked: ${event}`);
  clients.openWindow("/you-clicked-on-a-notification");

}

self.addEventListener("notificationclick", _handleNotif);

Where of course we'd add more to pass the details of the notification into the Flutter app, and let the plugin pull the data.

Update: Next on my to-do list: customizing notifications with details

[Levi-Lesches]

@MaikuB I'll once again put in my request to disable the always_specify_types and lines_longer_than_80_chars lints, as they cause a lot of headache when trying to write readable code here. Disabling them now won't require changing old code, but will allow cleaner code going forward, and there may be a fair amount of code since this is a big feature. I'll also point out again that always_specify_types contradicts Effective Dart and there are even replacements such as omit_obvious_local_variable_types and specify_nonobvious_local_variabletypes. As for line lengths, the new formatter will allow custom line lengths, for which I find 100 is a reasonable limit, especially with variable names as long as WebFlutterLocalNotificationsPlugin.