Check subscription validity using Flutters in-app-purchase plugin? - flutter

Question

I'm trying to implement in-app purchases using the official Flutter In-App-Purchase plugin. I've got things working, except I can't figure out how to tell if a users subscription is still active or if it expired. Even after I canceled my test subscription, the values I get after connecting and doing queryPastPurchases() are the same as when the subscription was active:
productId: test_subscription_1
transactiondate: 1565682346568
status: null
verificationData
source: IAPSource.GooglePlay
localVerificationData: {
"orderId":"GPA.1234-1234-1234-12345",
"packageName":"com.example.myapp",
"productId":"test_subscription_1",
"purchaseTime":1565682346568,
"purchaseState":0,
"purchaseToken":"<long string>",
"autoRenewing":false
}
serverVerificationData: "<long string>"
Am I supposed to simply hard code my subscription period and compare the current time to purchaseTime + the subscription period? Will that even work across auto-renewals? What if the user changes the date on his phone to a year ago? It seems like there should be some value that should either give me the expiration time or at least a boolean true/false to indicate if the subscription is still valid?

Answer 1

The official in-app purchase plugin handles making the purchase but doesn't supply all of the backend infrastructure you need to handle auto-renewing subscriptions specifically.
The short answer to your question is send this purchase info up to your server and manage subscription status there. Alternatively you can look into a managed solution like purchases_flutter: https://pub.dev/packages/purchases_flutter/

Answer 2

I have used ‘purchases_flutter‘ and the process is straightforward. You can check the status of the subscription by calling the methods which comes with the plugin. Check out this article which includes an example https://medium.com/flutter-community/in-app-purchases-with-flutter-a-comprehensive-step-by-step-tutorial-b96065d79a21

Answer 3

For anyone still having issues, there's a simple solution to validate the receipt on iOS
Here's a simple js snippet that you can use to fetch the actual receipt from Apple and use it to validate the subscription
Note
You will need to generate app specific password for the app from with apple developer account
Further help
https://developer.apple.com/documentation/appstorereceipts/expiration_intent
const axios = require('axios');
const iosValidateReceipt = async (transactionReceipt, isTest = true) =>
new Promise(async (resolve, reject) => {
const url = isTest ? 'https://sandbox.itunes.apple.com/verifyReceipt' : 'https://buy.itunes.apple.com/verifyReceipt';
const data = {
'receipt-data': transactionReceipt,
password: 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
};
console.log('iosValidateReceipt - input - ', { url, data });
try {
const response = await axios.post(url, data);
console.log('iosValidateReceipt - success - ', JSON.stringify(response.data, null, 2));
resolve(response.data);
} catch (err) {
console.log('iosValidateReceipt - error -', err);
reject(err);
}
});