iOS subscription expiry is not handled

[keesvandieren]

Please ensure you have given all the following requested information in your report.

Issue details, reproduction steps/code

The iOS Robovm implementation is not handling subscription expiry.

If you have ordered a subscription once, you currently have access for life.

Subscription receipts should be handled.

Version of gdx-pay and/or relevant dependencies

1.3.0

Stacktrace

N/A

Please select the affected platforms and payment service implementation

• [ X] apple robovm

[keesvandieren]

Parsing the Receipt seems to be fairly complicated. A Swift example is shown here:

https://github.com/andrewcbancroft/SwiftyLocalReceiptValidator/blob/master/ReceiptValidator.swift

Has anybody implemented this in Kotlin or Java?

[keesvandieren]

Related to: #167.

Approach I'm planning to follow:

• extend class Transaction with field subscriptionValidUntil. This will be filled with transaction startDate incremented with Product subscription incremented with Billing Grace Period (6 days for weekly, 16 days for longer subscriptions).
• use this field, to validate transactions in the Java logic.
• see if we can also populate this field in Google Play implementation.

Additionally, server validation can be used, but I currently have not enough time to implement that properly. Maybe in 2 or 3 months I have time

[keesvandieren]

After some more thinking, I am proposing the following changes to support basic end-date calculation in Google Play and App Store, without receipt verification:

• Rename class FreeTrialPeriod to SubscriptionPeriod
• Add Information.subscriptionPeriod
• Add field: Transaction.information, which is a reference to the related Gdx Information instance
• In Transaction, add a method: @Nullable public Date calculateMaximumUsageDate(int gracePeriodInDays). This uses Transaction.purchaseTime, adds the subscriptionPeriod, then adds the gracePeriodInDays, and returns that Date.

Apps have to maintain billing grace periods themself. On iOS App Store, the period is dictated by Apple; however, enabling or disabling billing grace period is to be chosen by the developer. On Google Play, the developer can choose whether to enable billing grace period, and, if enabled, can choose from a number of predefined values. Billing grace period is not exposed through payment apis (on Google Play and App Store).

External links:

• Google Play grace period
• App Store grace period

Eventually, we can add the billing grace period to Offer, but that would only work for Google Play, as for App Store it is decided by Apple. So that is why I prefer to keep it out.

@MrStahlfelge what do you think of this? (or any other reader interested in subscriptions)

[MrStahlfelge]

I am not really into subscriptions (don't using them), but what you suggest seems viable. As you are using subscriptions, best is if you try in your fork if it works out for you. And if it does, let's add it to gdx-pay!