I need a quick and easy way to store files with unique file names on iOS. I need to prefix the file with a string, and then append the generated unique identifier to the end. I was hoping NSFileManager
had some convenient method to do this, but I can't seem to find it.
I was looking at createFileAtPath:contents:attributes:
, but am unsure if the attributes will give me that unique file name.
Create your own file name:
CFUUIDRef uuid = CFUUIDCreate(NULL);
CFStringRef uuidString = CFUUIDCreateString(NULL, uuid);
CFRelease(uuid);
NSString *uniqueFileName = [NSString stringWithFormat:@"%@%@", prefixString, (NSString *)uuidString];
CFRelease(uuidString);
A simpler alternative proposed by @darrinm in the comments:
NSString *prefixString = @"MyFilename";
NSString *guid = [[NSProcessInfo processInfo] globallyUniqueString] ;
NSString *uniqueFileName = [NSString stringWithFormat:@"%@_%@", prefixString, guid];
NSLog(@"uniqueFileName: '%@'", uniqueFileName);
NSLog output:
uniqueFileName: 'MyFilename_680E77F2-20B8-444E-875B-11453B06606E-688-00000145B460AF51'
Note: iOS6 introduced the NSUUID class which can be used in place of CFUUID.
NSString *guid = [[NSUUID new] UUIDString];