How does data in the IOS In App Purchase flow travel exactly?

Question

I am working on a mobile app using Ionic (with Cordova purchase plugin) but this question is more general. We are using In App Purchases (IAP) and are currently getting an error when we try to finish the consumable purchase. Our current flow is like this:

• Get list of our Products from Apple and render on our IAP page
• User clicks consumable IAP they want and it fire off a message to StoreKit initiating the purchase
• We get a response with a consumable IAP object with the state set to approved.
• We initiate the verification procedure with a callback to our own server where we hit apple up to verify the purchase and then log it on our database and send the app a 200 response (not sure if we need to send back the IAP object here with receipt from our server or we just work with the one already inside the app?)
• We try finish the purchase where we get an error saying (InAppPurchase[objc]: Cannot finish transaction)

My question is assuming this is the correct flow what does the finish method do? Looking in the source code of the Cordova Purchase Plugin wrapper I can see it sets the state of the object to finished but I am assuming (I couldn't find the code where this happens) it also talks to Apple so that Apple marks the purchase as finished on their side? If we manually set the state to finished the IAP error goes away but the consumable can still not be purchased multiple times which means to me that Apple also need to close it. Is this a correct assumption? Any other tips to getting this to work would also be appreciated.

Answer 1

I'm not sure how cordova handles IAP, but on the apple side, the transaction needs to be finished by calling finishTransaction. It would appear thats the step thats not working.

One thing that might happen due to the delay in going to the server to validate is that the original transaction object has expired, and calling finishTransaction with it does nothing. At this point you might be able to search for your transaction in: [[SKPaymentQueue defaultQueue] transactions]

If you can grab it from there then call finishTransaction then it should work. Not sure how you do this with cordova but I hope this helps.