如何获取已存在共享的 CKShare 对象（获取共享 URL）

Question

我试图让我的应用程序的用户能够检索 iCloud 共享 link 到他们已经共享的记录。通过使用 let share = CKShare(rootRecord: CKRecord) 后跟 Apple 的 UISharingController 创建共享时，我可以获得 URL。但是，每次我使用这种方法时，旧的 link 就会失效并将其他人踢出他们已经加入的共享。我如何允许用户（记录所有者）随时获取记录 CKShare 对象的可共享 URL？

//Initially shares the record
let share = CKShare(rootRecord: newRecord)
share[CKShare.SystemFieldKey.title] = "Group" as CKRecordValue?        
let modifyRecordsOperation = CKModifyRecordsOperation( recordsToSave: [newRecord, share], recordIDsToDelete: nil)

//Activates the UISharingController (code not shown)

Answer 1

听起来您这里遇到了多个问题。我建议仔细阅读 UICloudSharingController documentation。

第一个问题是在您提供的代码中，您每次都创建一个新的共享，而您想要做的是创建一次，然后在您想要与之交互的任何时候显示该共享（包括获得份额 URL）。创建共享后，您可能希望以某种方式将其保留在设备上（它可以像将其存储在 UserDefaults 中一样简单）。

第二个问题是您似乎没有正确实例化 UICloudSharingController。当您最初创建 CKShare 时，您必须使用 UICloudSharingController init(preparationHandler:) 初始化程序并在其中创建共享。

根据不同初始化器的文档（强调我的）：

Important

You must initialize the controller with the correct initializer method. Do not use init(preparationHandler:) if the CKRecord is already shared. Likewise, do not use init(share:container:) if the CKRecord is not shared. Using the wrong initializer leads to errors when saving the record.

然后当您想要显示 shareSheet 时，您可以使用 UICloudSharingController init(share:container:) 初始化程序，并将您保存到设备的共享提供给它。

这是 UICloudSharingController 文档中提供的用于创建 CKShare 的代码：

func presentCloudSharingController(_ sender: Any) {  guard
    let barButtonItem = sender as? UIBarButtonItem,
    let rootRecord = self.recordToShare else {
    return
  }

  let cloudSharingController = UICloudSharingController { [weak self] (controller, completion: @escaping (CKShare?, CKContainer?, Error?) -> Void) in
    guard let `self` = self else {
      return
    }
    self.share(rootRecord: rootRecord, completion: completion)
  }

  if let popover = cloudSharingController.popoverPresentationController {
    popover.barButtonItem = barButtonItem
  }
  self.present(cloudSharingController, animated: true) {}
}

func share(rootRecord: CKRecord, completion: @escaping (CKShare?, CKContainer?, Error?) -> Void) {
  let shareRecord = CKShare(rootRecord: rootRecord)
  let recordsToSave = [rootRecord, shareRecord];
  let container = CKContainer.default()
  let privateDatabase = container.privateCloudDatabase
  let operation = CKModifyRecordsOperation(recordsToSave: recordsToSave, recordIDsToDelete: []) 
  operation.perRecordCompletionBlock = { (record, error) in
    if let error = error {
      print("CloudKit error: \(error.localizedDescription)")
    }
  }

  operation.modifyRecordsCompletionBlock = { (savedRecords, deletedRecordIDs, error) in
    if let error = error {
      completion(nil, nil, error)
    } else {
      completion(shareRecord, container, nil)
    }
  }

  privateDatabase.add(operation)
}

下次你想展示它的时候，它会更加前卫：

 let share = // yourCKShare
 let container = // yourCKContainer
 let viewController = // yourViewController
 let shareController = UICloudSharingController(share: share, container: container)
 viewController.present(shareController, animated: true)

最后，为了回答问题的 URL 部分，UICloudSharingController 用于所有内容共享 - 当控制器呈现共享时，所有者可以使用 "Copy Link" 按钮（如果您允许 public 访问，可能还有用户 - 我没有看过，因为我的东西是私人的）：

Answer 2

假设记录已经共享，您可以获得 URL 以邀请其他参与者，方法如下：

if let shareReference = record.share {
    database.fetch(withRecordID: shareReference.recordID) { (share, error) in
        let shareURL = (share as? CKShare)?.url
    }
}

如果您想再次显示现有共享的 UICloudSharingController（不生成新的 URL），您可以这样做：

let sharingController = UICloudSharingController { (_, prepareCompletionHandler) in

    func createNewShare() {
        let operationQueue = OperationQueue()
        operationQueue.maxConcurrentOperationCount = 1

        let share = CKShare(rootRecord: record)
        share[CKShare.SystemFieldKey.title] = "Title" as CKRecordValue
        share.publicPermission = .readWrite

        let modifyRecordsOp = CKModifyRecordsOperation(recordsToSave: [share, record], recordIDsToDelete: nil)
        modifyRecordsOp.modifyRecordsCompletionBlock = { records, recordIDs, error in
            prepareCompletionHandler(share, self, error)
        }
        modifyRecordsOp.database = database
        operationQueue.addOperation(modifyRecordsOp)
    }

    if let shareReference = record.share {
        database.fetch(withRecordID: shareReference.recordID) { (share, error) in
            guard let share = share as? CKShare else {
                createNewShare()
                return
            }
            prepareCompletionHandler(share, self, nil)
        }
    } else {
        createNewShare()
    }
}

如何获取已存在共享的 CKShare 对象（获取共享 URL）

How to fetch the CKShare object of an already existing share (to get share URL)

ios

swift

cloudkit

cloudkit-sharing