get extension's human friendly description of a given extension

Question

I'm sure there's a way to get a human friendly description of a file's extension in objective-c - cocoa. For example: given an extension "pdf" to get "Portable Document Format", or given "app" -> "Application", or "txt" -> "Plain Text", etc.

Answer 1

You can do it with some the UT* functions:

NSString * humanReadableStringForExtension(NSString * extension) {
    CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (CFStringRef)extension, NULL);
    NSString * extensionDescription = (NSString *)UTTypeCopyDescription(UTI);
    CFRelease(UTI);
    return [extensionDescription autorelease];
}

You can then do stuff like:

NSLog(@"pdf: %@", humanReadableStringForExtension(@"pdf"));
NSLog(@"txt: %@", humanReadableStringForExtension(@"txt"));
NSLog(@"app: %@", humanReadableStringForExtension(@"app"));

Which will log:

pdf: Portable Document Format (PDF)
txt: text
app: application

(woot, my 1000th answer!)