CKError localizedDescription

Question

Aim

• I would like to display the CKError encountered to the user in the app as an alert.
• So I would like to extract the string from the error that can be displayed to the user.

Note: This question is not about UI code to display. Just want to extract a meaningful string from the error.

I tried to use localizedDescription but it doesn't seem to contain an appropriate string

Code:

Given below are the attempts I made:

po error  
<CKError 0x1c464cea0: "Network Unavailable" (3/NSURLErrorDomain:-1009); "The Internet connection appears to be offline.">  

po error.localizedDescription  
"The operation couldn’t be completed. (CKErrorDomain error 3.)"  

po (error as! CKError).errorUserInfo  
▿ 2 elements  
  ▿ 0 : 2 elements  
    - key : "NSUnderlyingError"  
    - value : Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={NSErrorFailingURLStringKey=https:/  
  ▿ 1 : 2 elements  
    - key : "NSDebugDescription"  
    - value : NSURLErrorDomain: -1009  



po (error as? NSError)?.localizedFailureReason  
nil  

po (error as? NSError)?.localizedRecoverySuggestion  
nil  

po (error as? NSError)?.localizedRecoveryOptions  
nil  

po (error as? NSError)?.debugDescription  
▿ Optional<String>  
  - some : "<CKError 0x1c064eaf0: \"Network Unavailable\" (3/NSURLErrorDomain:-1009); \"The Internet connection appears to be offline.\">"  

Questions:

The debug description seems to be the closest to what I want.

1. Am I missing something ?
2. What is the correct way to extract the error string that I can display to the user ?

Answer 1

Looks like there is another error in the errorUserInfo[NSUnderlyingError]. Try getting the localizedDescription from that error.

So, that would be:

((error as? CKError)?.errorUserInfo[NSUnderlyingErrorKey] as? NSError)?.localizedDescription

Answer 2

I'm not proud of it, but this is what I resorted to. There must be a better way!

public func ckErrorCodeToText(code: CKError.Code) -> String {
    switch code {
    case .alreadyShared: return "alreadyShared"
    case .internalError: return "internalError"
    case .partialFailure: return "partialFailure"
    case .networkUnavailable: return "networkUnavailable"
    case .networkFailure: return "networkFailure"
    case .badContainer: return "badContainer"
    case .serviceUnavailable: return "serviceUnavailable"
    case .requestRateLimited: return "requestRateLimited"
    case .missingEntitlement: return "missingEntitlement"
    case .notAuthenticated: return "notAuthenticated"
    case .permissionFailure: return "permissionFailure"
    case .unknownItem: return "unknownItem"
    case .invalidArguments: return "invalidArguments"
    case .resultsTruncated: return "resultsTruncated"
    case .serverRecordChanged: return "serverRecordChanged"
    case .serverRejectedRequest: return "serverRejectedRequest"
    case .assetFileNotFound: return "assetFileNotFound"
    case .assetFileModified: return "assetFileModified"
    case .incompatibleVersion: return "incompatibleVersion"
    case .constraintViolation: return "constraintViolation"
    case .operationCancelled: return "operationCancelled"
    case .changeTokenExpired: return "changeTokenExpired"
    case .batchRequestFailed: return "batchRequestFailed"
    case .zoneBusy: return "zoneBusy"
    case .badDatabase: return "badDatabase"
    case .quotaExceeded: return "quotaExceeded"
    case .zoneNotFound: return "zoneNotFound"
    case .limitExceeded: return "limitExceeded"
    case .userDeletedZone: return "userDeletedZone"
    case .tooManyParticipants: return "tooManyParticipants"
    case .referenceViolation: return "referenceViolation"
    case .managedAccountRestricted: return "managedAccountRestricted"
    case .participantMayNeedVerification: return "participantMayNeedVerification"
    case .serverResponseLost: return "serverResponseLost"
    case .assetNotAvailable: return "assetNotAvailable"
    @unknown default: return String(code.rawValue)
    }
}

Answer 3

The error.localizedDescription is really all you have to work with from the error itself.

Your app can provide a better error message (more user-friendly, localized, etc.) by checking for the error code and providing its own message to the user.

(error as? NSError)?.code