Deduction Result Notification API
After the deduction is completed, wechat will send the relevant payment results and user information to the merchant in the form of data flow.
● The same notification may be sent to the merchant system multiple times. The merchant system must be able to process duplicate notifications properly. First check the status of the corresponding business data when receiving a notification for processing, and determine whether the notification has been processed. If not, the notification should be processed; if it has been processed, the success result should be returned. Before status checking and processing of the business data, a data lock should be used to implement concurrency control and avoid data confusion caused by function reentry.
● The merchant system must perform signature verification for the content of the notification, and verify whether the data fields of the notification are consistent with those of the merchant side, thus preventing a "false notification" caused by data leakage and capital loss.