How could one build a consumable subscription based service into an app? (Assuming the service had some usage cost)

Question

The examples I've seen are for games and there is no service use. The thinking so far is to require the user to authenticate and track consumption for a user, at the service until all units are consumed. However would it be possible without requiring the user to authenticate, by validating the receipt on the server and tracking the consumption against this? (Can anyone see any pitfalls, I've just started thinking about this and it's more of a discussion) Many thanks.

Answer 1

On a Windows device you can easily and securely save user credential in Windows Credential manager and avoid a situation of requesting it again and again from user.

If you think that is not the way you want to do it and rather use digital receipt; then also it should be good. In this case that receipt should be small enough that it can be stored within Windows Credential Manager as a password as then no one will be able to extract it from Machine except for your own App. In this case you can simply sell this digital receipt outside the app on some website and user can import it in App for his/her use.

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Answer 2

I'm doing exactly that type of thing.

I have a business cloud service that the app user puts their content on, and their clients then access.  They purchase 30,60,90, or 365 day 'subscription' package from my windows store IAP (all those are consumable products.)  When the purchase is made, I update my server with the corresponding time, verify the purchase, and update my accounting there.

The hardest part I've encountered so far is the state machine that handles integration between the Windows Store and my server's accounting system to add time to the right account.  For example, if you make the store purchase and then can't somehow update your server, or you do those first two items and then can't report the consumable as received, that sort of thing can get tricky.

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Darin R.