Any documentation on how a pass is updated from a web service

[steinm]

Is there any documentation explaining the update of a pass by using the webServiceUrl stored in the json data? Is this implemented at all?

[SeineEloquenz]

Hi, yes this is implemented (somehow-ish).
Apples documentation is here.

If you look at the diagram, we only implement the "Gets Pass" call. Everything to do with registration for push notifications is not implemented as we are not an Apple device.

When pressing the update button the App simply calls the vendor server's api with the pass id and authentication token and gets handed the current version of the pass). This is also what happens when the app updates passes in the background automatically.

We can't really check whether downloading the whole pass is necessary beforehand, sadly. To do so we would need to register the device for push notifications so we get a device id, but registrations are purged if push notifications fail so we can't do that.

If you have a suggestion to improve this behavior, I'd be happy about it.

[steinm]

This reason I was asking, is an approach I started about 2 years ago when I had discovered PassAndroid. I implemented the server side to deliver the passes. I even did the registration of clients but got stuck when implementing the push service.
Actually, I'm not familiar with app development but I though, that unified push and ntfy could be an option to implement the push service. I maybe completely on the wrong track but wouldn't it be sufficient to have a server implementing the communication described at https://developer.apple.com/library/archive/documentation/UserExperience/Conceptual/PassKit_PG/Updating.html and some push service?

[SeineEloquenz]

This would in theory be possible for your own Web-Service, sure. The problem with this approach how I understand however is that all the other pass web services out there only talk to APN, and not a different push server. Sadly as this is a proprietary standard, there is no way to specify a push server in the protocol.

[steinm]

Is there any need to specify a push server in the protocol? Can't you just determine which push service is supported by your app and than the server must implement it. All endpoints 'Register for updates', 'Get changes', 'Get pass' and 'Unregister for updates' are independent of the push service. Your app may not be able to retrieve notifications from APN, but why not use a different one, if the server supports it?

[SeineEloquenz]

Yes you could do that, but then it'd be a separate protocol. The protocol specified by Apple only works with APN. And the problem with the endpoints "Register for updates", "Get changes" and "Unregister for Updates" is that they depend on a device registration which gets purged if APN can not deliver push notifications.