CloudKit CKError extension not available in Objective-C? - ios

Question

I read somewhere here that CKError is not available in Objective-C, and I concur. For instance, this extension is available in Swift.
#available(OSX 10.10, iOS 8.0, watchOS 3.0, *)
extension CKError {
/// Retrieve partial error results associated by item ID.
public var partialErrorsByItemID: [AnyHashable : Error]? { get }
/// The original CKRecord object that you used as the basis for
/// making your changes.
public var ancestorRecord: CKRecord? { get }
/// The CKRecord object that was found on the server. Use this
/// record as the basis for merging your changes.
public var serverRecord: CKRecord? { get }
/// The CKRecord object that you tried to save. This record is based
/// on the record in the CKRecordChangedErrorAncestorRecordKey key
/// but contains the additional changes you made.
public var clientRecord: CKRecord? { get }
/// The number of seconds after which you may retry a request. This
/// key may be included in an error of type
/// `CKErrorServiceUnavailable` or `CKErrorRequestRateLimited`.
public var retryAfterSeconds: Double? { get }
}
The problem is that I need these objects in my Objective-C project.
I've somehow (I believe) managed to get the partialErrorsByItemID in Objective-C by making a category for NSError and a little comprehension of the documentation of CKError.h, like so:
CKErrorCode ckErrorCode = (CKErrorCode) _code;
if (ckErrorCode == CKErrorPartialFailure) {
// When a CKErrorPartialFailure happens this key will be set in the error's userInfo dictionary.
// The value of this key will be a dictionary, and the values will be errors for individual items with the keys being the item IDs that failed.
NSDictionary *dicError = _userInfo;
if ([dicError objectForKey:CKPartialErrorsByItemIDKey] != nil) {
NSDictionary *dic = (NSDictionary *)[dicError objectForKey:CKPartialErrorsByItemIDKey];
for (NSString* key in dic) {
NSError *newError = dic[key];
if (code == newError.code) {
match = YES;
}
}
} else {
return NO;
}
}
But again, my problem is how to get the objects serverRecord and the clientRecord. Any idea?

Answer 1

Here's an Objective-C category that replicates most of the CKError structure of Swift. I didn't add errorCode, localizedDescription or errorUserInfo since NSError already provides those as code, localizedDescription, and userInfo.
CloudKitExtensions.h
#import <CloudKit/CloudKit.h>
NS_ASSUME_NONNULL_BEGIN
extern const double UnknownRetrySeconds;
#interface NSError (CKError)
- (NSDictionary<id, NSError *> * _Nullable)partialErrorsByItemID;
- (CKRecord * _Nullable)ancestorRecord;
- (CKRecord * _Nullable)clientRecord;
- (CKRecord * _Nullable)serverRecord;
- (double)retryAfterSeconds; // returns UnknownRetrySeconds if not available
#end
NS_ASSUME_NONNULL_END
CloudKitExtensions.m
#import "CloudKitExtensions.h"
const double UnknownRetrySeconds = -1;
#implementation NSError (CKError)
- (NSDictionary<id, NSError *> * _Nullable)partialErrorsByItemID {
if ([self.domain isEqualToString:CKErrorDomain] && self.code == CKErrorPartialFailure) {
return self.userInfo[CKPartialErrorsByItemIDKey];
} else {
return nil;
}
}
- (CKRecord * _Nullable)ancestorRecord {
if ([self.domain isEqualToString:CKErrorDomain] && self.code == CKErrorServerRecordChanged) {
return self.userInfo[CKRecordChangedErrorAncestorRecordKey];
} else {
return nil;
}
}
- (CKRecord * _Nullable)clientRecord {
if ([self.domain isEqualToString:CKErrorDomain] && self.code == CKErrorServerRecordChanged) {
return self.userInfo[CKRecordChangedErrorClientRecordKey];
} else {
return nil;
}
}
- (CKRecord * _Nullable)serverRecord {
if ([self.domain isEqualToString:CKErrorDomain] && self.code == CKErrorServerRecordChanged) {
return self.userInfo[CKRecordChangedErrorServerRecordKey];
} else {
return nil;
}
}
- (double)retryAfterSeconds {
if ([self.domain isEqualToString:CKErrorDomain]) {
NSNumber *delayVal = self.userInfo[CKErrorRetryAfterKey];
return delayVal ? [delayVal doubleValue] : UnknownRetrySeconds;
} else {
return UnknownRetrySeconds;
}
}
#end