swift - 如何对大量入站 CloudKit 通知进行排队

Question

假设我使用 CKModifyRecordsOperation 向 CloudKit 保存 50 条记录，如下所示:

let operation = CKModifyRecordsOperation(recordsToSave: records, recordIDsToDelete: nil)
operation.savePolicy = .changedKeys

operation.modifyRecordsCompletionBlock = { records, _, error in
    //...
}

privateDB.add(operation)

在我的其他设备上，对于每个发生更改的 CKRecord，我都会收到 50 种不同的后台通知。很好，我希望如此。

我像这样处理每个入站通知:

func processCloudKitNotification(notification: CKNotification, database: CKDatabase){

  guard let notification = notification as? CKQueryNotification else { return }

  if let recordID = notification.recordID{
    var recordIDs = [CKRecordID]()

    switch notification.queryNotificationReason {
      case .recordDeleted:
        //Delete [-]
        //...
      default:
        //Add and Edit [+ /]
        recordIDs.append(recordID)
    }

    let fetchOperation = CKFetchRecordsOperation(recordIDs: recordIDs)

    fetchOperation.fetchRecordsCompletionBlock = { records, error in
      //...
    }

    database.add(fetchOperation)
  }
}

但是，由于 50 个传入通知中的每一个都是单独的事件，因此该函数会被调用 50 次不同的时间，从而触发大量请求，以使用通知提供的 CKRecordID 获取完整记录我。

如何在合理的时间段内对所有传入通知 CKRecordID 进行排队，以便我可以使用多个 recordID 发出更高效的 CKFetchRecordsOperation 请求一次？

Answer 1

我最终为此使用了一个计时器，而且效果很好。基本上，当新的推送通知到来时，我会启动一个计时器，并且每次收到额外的通知时都会重置它。同时，我收集所有传入的 CKRecordID，然后在计时器触发时处理它们(这发生在通知停止流入之后)。

这是我的代码:

var collectNotificationsTimer: Timer?
var recordIDsFromNotifications = [CKRecordID]()

func processCloudKitNotification(notification: CKNotification, database: CKDatabase){

  guard let notification = notification as? CKQueryNotification else { return }
  guard let recordID = notification.recordID else { return }

  //:: 1 :: Collect record IDs from incoming notifications
  if notification.queryNotificationReason == .recordDeleted{
    //Delete [-]
    //...
  }else{
    //Add and Edit [+ /]
    recordIDsFromNotifications.append(recordID)

    //:: 2 :: After collecting IDs for 1 second, request a batch of updated records
    collectNotificationsTimer?.invalidate()
    collectNotificationsTimer = Timer.scheduledTimer(withTimeInterval: 1, repeats: false){ _ in

      let fetchOperation = CKFetchRecordsOperation(recordIDs: recordIDsFromNotifications)

      fetchOperation.fetchRecordsCompletionBlock = { records, error in
        recordIDsFromNotifications.removeAll()

        if let error = error {
          checkCloudKitErrorAndRetryRequest(name: "fetchRecordsCompletionBlock", error: error){}
        }else{
          if let records = records{
            //Save records...
          }
        }
      }
      database.add(fetchOperation)
    }
  }
}