Question

Auto renewable subscription has one id but can have multiple durations.
I was wondering how can i specify duration user choose to buy but there is no such field as “duration” in SKProduct.
Question: is it correct that it’s impossible to choose duration of auto-renewable subscription in code but instead user chooses one in native dialog?

Answer 1

The duration you have to infer from product id in iTunes. There is no other alternative.
As par Apple Documentation

The length of the subscription is not provided in by the
SKPaymentTransaction object or in the receipt data returned by the App
Store receipt validator. You should use a different product identifier
for each subscription length so that your application can convert a
product identifier into a subscription length.

E.g. com.mycompany.6monthssub
com.mycompany.1yearsub