CKAsset in server record contains no fileURL, cannot even check for nil

问题

I am testing a sync conflict when I save a record that contains a CKAsset (simply a JPG image) using CKModifyRecordsOperation with a save policy of .IfServerRecordUnchanged. I am getting the error CKErrorCode.ServerRecordChanged. This CKError returns me useful information for conflict resolution, including the CKRecord I tried to save, and the current server version of the record. The first is in error.userInfo[CKRecordChangedErrorClientRecordKey] the second is in error.userInfo[CKRecordChangedErrorServerRecordKey].

My problem is I am trying to access the server record's CKAsset with this code:

if let photoAsset = rec["myPhoto"] as? CKAsset {
  print("PhotoAsset.fileURL: \(photoAsset.fileURL)")  // BAD_ACCESS ERROR HERE
  self.myPartner.photo = NSData(contentsOfURL: photoAsset.fileURL)
}

I don't get how this is possible. But after further investigating, I print out the client and server CKRecords and the server one is missing the 'path' property.

client CKAsset...myPhoto (modified) -> CKAsset: 0x7b960d90; path=~/tmp/BF185B2C-7A39-4730-9530-9797E843243Aphoto, size=373959, uploadRank=0, uploadReceipt=A92Eg1qoyPG7yrg3, UUID=3C2D5DC8-4FF5-4A81-853B-395FC1C59862, referenceSignature=<012fd149 200fc600 617e3907 88763e3e 5002abbf 5b>, flags=uploaded, wrappedEncryptionKey=, signature=<0134a297 38d52f5f 9275bfba fce5b1a8 3d6b9692 d3>

server CKAsset...myPhoto = CKAsset: 0x7be700d0; referenceSignature=<015337bd 84409893 7c014f46 36248d27 ce911dc3 7a>, size=373959, uploadRank=0, UUID=DF5D2EB4-033C-49A2-AF52-6055B5A44106, wrappedEncryptionKey=<767e7cfd d1e62110 32119ee9 f6f026b3 5bcf0cc3 8053a4de>, signature=<0134a297 38d52f5f 9275bfba fce5b1a8 3d6b9692 d3>

Notice how path=~/tmp/C706423B-A3E8-4051-A9B3-483C718BFBF5photo is missing from the server one? Can anyone explain this? To fix it I try to avoid touching the CKAsset from the server record. I would like to at least be able to check for nil. I wanted to put this out there in case it helps anyone else.

回答1:

Due to the crash on accessing fileURL, this is most likely a framework bug. Probably an oversight on account of the CKRecord being buried in a dictionary. I just follow it up with a regular fetch(withRecordID:).

回答2:

I'm experiencing this issue as well on iOS 11.2.1 when accessing CKAsset from serverRecord property in CKRecord. It's a little bit frustrating. A workaround is fetching the object once again via func fetch(withRecordID... and then access fileURL.

来源：https://stackoverflow.com/questions/41072510/ckasset-in-server-record-contains-no-fileurl-cannot-even-check-for-nil

标签

swift

cloudkit

ckasset

ckerror