How to verify purchase with data from in_app_purchase_ios flutter package?

[apple]

How to verify purchase with data from in_app_purchase_ios flutter package?

[alexanderjordanbaker]

We would recommend using StoreKit 2 client side, which would give you a signed JWS you can pass directly to the server. I'm not familiar with whether that library is using Original StoreKit or StoreKit 2 or what that field represents.

[Apidcloud]

Apologies for reopening the thread but I'm facing the same issue.

the serverVerificationData is something like this:
MIIUZwYJ<.......more>9rxE3Q==

and it's something that seems to work with the receipt utility extractTransactionIdFromAppReceipt, so im assuming the flutter package is using the original store kit.

My question now is: what is the correct way of validating the purchase? In my mind it would be something like searching if the receipt coming from the app was already paid or not, but I'm a bit confused with the example in README in this repo for Receipt usage.

It loops over the transaction history, but when can consider it valid and effectively purchased? And the opposite: when can we consider it invalid?

Thanks!