In-App Purchase--Auto-Renewable Subscriptions[8]

Auto-Renewable Subscriptions

Note: Subscriptions(订阅) are available only on iOS.

 

In-App Purchase provides a standardized（标准话） way to implement auto-renewable subscriptions. Auto-renewable subscriptions have a few notable（显著） characteristics（特点）:

• When you configure an auto-renewable subscription in iTunes Connect, you also configure the duration for the subscription and other marketing options（市场营销）.
• Auto-renewable subscriptions are restored automatically using the same Store Kit functions used to restore non-consumable products. The original purchase transaction as well a transaction for each renewal are sent to your application. See “Restoring Transactions.”
• When your server verifies a receipt with the App Store and the subscription is both active and has been renewed by the App Store, the App Store returns an updated receipt to your application.

Adding Auto-Renewable Subscriptions to Your Store

To implement auto-renewable subscriptions, follow these steps:

• Connect to iTunes Connect and use it to create a new shared secret. A shared secret is a password that your server must provide when validating receipts for auto-renewable subscriptions. This shared secret provides an additional layer of security to your transactions with the App Store. See iTunes Connect Developer Guide.
• Configure new products in iTunes Connect with the new auto-renewable subscription type.
• Modify your server’s receipt verification code so that it adds the shared secret to the JSON data it sends to the App Store. Your server’s verification code must parse the response to determine whether the subscription has expired（过期）. If the subscription has been renewed（续约） by the user, the most current receipt（收据，凭证） is also returned to your server.

Designing your Client Application

In most cases, your client application should require minimal changes to support auto-renewable subscriptions. In fact, your client application is now made simpler, as you can use the same code to recover auto-renewable subscriptions as you do to recover non-consumable products. Your application receives a separate transaction for each period of time where the subscription was renewed; your application should verify each receipt separately.

Verifying an Auto-renewable Subscription Receipt

Verifying a receipt for an auto-renewable subscription is almost identical（相同） to the process described in “Verifying Store Receipts.” Your application creates a JSON object and posts it to the App Store. The JSON object for an auto-renewable subscription receipt must include a second parameter — the shared secret you created earlier on iTunes Connect:

{

"receipt-data" : "(receipt bytes here)",

"password"     : "(shared secret bytes here)"

}

The response includes a status field that indicates whether the receipt was successfully validated.

{

"status" : 0,

"receipt" : { (receipt here) },

"latest_receipt" : "(base-64 encoded receipt here)",

"latest_receipt_info" : { (latest receipt info here) }

}

If the user’s receipt was valid and the subscription is active, the status field holds 0, and the receipt field is populated with the decoded receipt data. If your server receives a non-zero status value, use Table 7-1 to interpret（诠释） non-zero status codes.

Table 7-1  Status codes for auto-renewable subscriptions

Status Code	Description
21000	The App Store could not read the JSON object you provided.
21002	The data in the receipt-data property was malformed（异常）.
21003	The receipt could not be authenticated.
21004	The shared secret you provided does not match the shared secret on file for your account.
21005	The receipt server is not currently available.
21006	This receipt is valid but the subscription has expired（过期）. When this status code is returned to your server, the receipt data is also decoded and returned as part of the response.
21007	This receipt is a sandbox receipt, but it was sent to the production service for verification.
21008	This receipt is a production receipt, but it was sent to the sandbox service for verification.

Important The non-zero status codes here apply only when recovering information about a auto-renewable subscription. Do not use these status codes when testing responses for other kinds of products.

 

The receipt field on the JSON object holds the parsed information from the receipt. The receipt data for an auto-renewable subscription includes one additional key, and some other key previously described in Table 5-1 are modified slightly for subscriptions. See Table 7-2 for details on the new and modified keys.

Table 7-2  Auto-renewable subscription info keys

Key	Description
expires_date	The expiration date of the subscription receipt, expressed as the number of milliseconds since January 1, 1970, 00:00:00 GMT. This key is not included on restored transactions.
original_transaction_id	This holds the transaction identifier for the initial purchase. All subsequent renewals of this subscription and recovered transactions all share this identifier.
original_purchase_date	This holds the purchase date for the initial purchase; it represents the start date for the subscription.
purchase_date	This holds the billing date when this transaction occurred. For a transaction for a renewable subscription, this would be the date when the subscription was renewed. If the receipt being parsed by the App Store was the latest receipt for this subscription, this field holds the date when this subscription was most recently renewed.

In addition to the receipt_data field, the response may also include two new fields. If the user’s subscription is active and was renewed by a transaction that took place after the receipt your server sent to the App Store, the latest_receipt field includes a base-64 encoded receipt for the last renewal for this subscription. The decoded data for this new receipt is also provided in the latest_expired_receipt_info field. Your server can use this new receipt to maintain a record of the most recent renewal.

Restoring Auto-Renewable Subscriptions

The App Store creates a separate transaction each time it renews a subscription. When your application restores previous purchases, Store Kit delivers each transaction to your application. To restore the content for this purchase, your application should combine the purchase date of each transaction with the length of the subscription. 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. Then, use this length and the purchase date to determine the interval(间隔、间隙树)over which this receipt was valid（有效的）.

 

THE END !