The two conversion methods below for mapping between the PHPhoto localIdentifier to the corresponding cloudIdentifier work but it feels too heavy. Do you have suggestions on how to rewrite to a more elegant (easier to read) form?
The sample code in the Apple documentation found in PHCloudIdentifier https://developer.apple.com/documentation/photokit/phcloudidentifier/ does not compile in xCode 13.2.1.
It was difficult to rewrite the sample code because I made the mistake of interpreting the Result type as a tuple. Result type is really an enum.
func localId2CloudId(localIdentifiers: [String]) -> [String] {
var mappedIdentifiers = [String]()
let library = PHPhotoLibrary.shared()
let iCloudIDs = library.cloudIdentifierMappings(forLocalIdentifiers: localIdentifiers)
for aCloudID in iCloudIDs {
//'Dictionary<String, Result<PHCloudIdentifier, Error>>.Element' (aka '(key: String, value: Result<PHCloudIdentifier, Error>)')
let cloudResult: Result = aCloudID.value
// Result is an enum .. not a tuple
switch cloudResult {
case .success(let success):
let newValue = success.stringValue
mappedIdentifiers.append(newValue)
case .failure(let failure):
// do error notify to user
let iCloudError = savePhotoError.otherSaveError // need to notify user
}
}
return mappedIdentifiers
}
func cloudId2LocalId(assetCloudIdentifiers: [PHCloudIdentifier]) -> [String] {
// patterned error handling per documentation
var localIDs = [String]()
let localIdentifiers: [PHCloudIdentifier: Result<String, Error>]
= PHPhotoLibrary
.shared()
.localIdentifierMappings(
for: assetCloudIdentifiers)
for cloudIdentifier in assetCloudIdentifiers {
guard let identifierMapping = localIdentifiers[cloudIdentifier] else {
print("Failed to find a mapping for \(cloudIdentifier).")
continue
}
switch identifierMapping {
case .success(let success):
localIDs.append(success)
case .failure(let failure) :
let thisError = failure as? PHPhotosError
switch thisError?.code {
case .identifierNotFound:
// Skip the missing or deleted assets.
print("Failed to find the local identifier for \(cloudIdentifier). \(String(describing: thisError?.localizedDescription)))")
case .multipleIdentifiersFound:
// Prompt the user to resolve the cloud identifier that matched multiple assets.
default:
print("Encountered an unexpected error looking up the local identifier for \(cloudIdentifier). \(String(describing: thisError?.localizedDescription))")
}
}
}
return localIDs
}
