Implement WidgetKit push notification to keep widget in sync

[bgoncal]

Description

To provide more reliable widget updates, implement WidgetKit push token updates
https://developer.apple.com/documentation/WidgetKit/Updating-widgets-with-widgetkit-push-notifications

Additional context

No response

[hariharanjagan]

I want to contribute for this ticket

[bgoncal]

@hariharanjagan cool, feel free to start looking into it and open PRs.

At a glance I think you will need to open a PR to core to store widget push tokens in the mobile_app integration as well was iOS codebase to handle sending the token and receiving the push.

And finally also the mobile-fcm repo (firebase) to format the push for the app.

A heads up: mobile_app integration in core should have platform agnostic code as much as possible, so if you can, build this token exchange in a way that apps can just say "hey, this is my token, whenever X entity changes send a push using this token"

[hariharanjagan]

@bgoncal : i tried give PR in Core home-assistant/core#174943 and i am getting error for
docs-missing — Please open a documentation PR. can you please help me with this so i can futher proceed with FCM and iOS PR's

[bgoncal]

You can leave the document for the end of your implementation, since it will touch different pieces of home assistant.

Just make sure the full flow is working, passing tests locally and address reviews from core developers.

[hariharanjagan]

@bgoncal I want to make sure that WidgetKit push notification only supports from iOS 26 (@available(iOS 26, *). Also the Widget extension's need push Notification capabality, App ID needs the Push Notifications capability enabled in the Apple Developer portal, and the provisioning profile

[bgoncal]

Are you sure those capabilities needs to be enabled? I thought only the main app could have them. We use push tokens for live activities already and the current setup already works

[hariharanjagan]

[bgoncal]

Ok, thats news to me, good to know, can you continue the development using your own credentials? I can have a look on the final solution and then add the required capabilities in developer's portal in the end.

[bgoncal]

Unfortunately I cannot do that, nowadays Apple's free dev account is already capable of doing such, you can even run apps on physical devices (which wasn't possible before).

Btw I was reading live activity docs and it mentions the same thing you sent to me, but we have it in the app already and ir works so.. did you try using whats already in-place?

[hariharanjagan]

If you can once check the Widget target there is no Push Notification capability. I just added it let have a look and get back you

[bgoncal]

Yeah, I checked that when you mentioned that above, but since live activities docs require the same I thought maybe it would work for you too, check and let me know.

[bgoncal]

I am on discord btw, if you want chat (@ bgoncal2)

[hariharanjagan]

Hi @bgoncal

Open question — the relay (mobile-apps-fcm-push)

This is where I'd like your steer. The relay can't send the widget push via FCM:

• handlers.js rejects the token (token.indexOf(':') === -1 → 403) because the
  widget token is raw APNs hex, not an FCM token.
• messaging.send() routes by FCM registration token anyway, and firebase-admin
  (13.5.0) has no widget-token field like apns.liveActivityToken.
• Live Activities dodge this by sending both the FCM token and the LA token;
  the widget flow currently sends only the widget token.

Sending directly to APNs from the relay works (that's what I tested). So I think
the relay needs a push_subscription → direct-APNs branch (Node http2 + a .p8).
Is that the direction you'd want, or did you have a different relay design in mind?

[bgoncal]

Please do not use AI for our direct communication.

If I understood correctly you first were trying to replace the token to have just 1 sent, that won't work indeed, different tokens serve to different purposes, as you already noted, you need to send an extra token which is the widget push token.