Where's the iPhone MIME type database?

Question

I have a program for the iPhone that is supposed to be doing intelligent things (picking out appropriate icons for file types) given a list of filenames. I\'m looking for t

Answer 1

The following function will return the mime-type for a given file extension in Swift 2

import MobileCoreServices

func mimeTypeFromFileExtension(fileExtension: String) -> String? {
    guard let uti: CFString = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, fileExtension as NSString, nil)?.takeRetainedValue() else {
        return nil
    }

    guard let mimeType: CFString = UTTypeCopyPreferredTagWithClass(uti, kUTTagClassMIMEType)?.takeRetainedValue() else {
        return nil
    }

    return mimeType as String
}

Answer 2

Updating the great and accepted answer to Swift 5.3, as an URL extension

extension URL {
    var mime: String {
        guard
            let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, pathExtension as CFString, nil)
        else { return "" }
        let mime = uti.takeRetainedValue() as String
        uti.release()
        return mime
    }
}

Answer 3

In obj-C, warning to memory leaks when using C.

- (NSString *)guessMIMETypeFromFileName: (NSString *)fileName {
    CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (__bridge CFStringRef)[fileName pathExtension], NULL);
    CFStringRef MIMEType = UTTypeCopyPreferredTagWithClass(UTI, kUTTagClassMIMEType);
    CFRelease(UTI);
    if (!MIMEType) {
        return @"application/octet-stream";
    }
    NSString *dest = [NSString stringWithString:(__bridge NSString *)(MIMEType)];
    CFRelease(MIMEType);

    return dest;
}

Answer 4

If it did, your app surely wouldn't have permissions to even read it directly. What are you trying to do?

EDIT

This is a function I wrote a while ago. I wrote it for the Mac, but it looks like the same functions exist on the iPhone. Basically, you give it a filename, and it uses the path extension to return the file's MIME type:

#import <MobileCoreServices/MobileCoreServices.h>
...
- (NSString*) fileMIMEType:(NSString*) file {
    CFStringRef UTI = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (CFStringRef)[file pathExtension], NULL);
    CFStringRef MIMEType = UTTypeCopyPreferredTagWithClass (UTI, kUTTagClassMIMEType);
    CFRelease(UTI);
    return [(NSString *)MIMEType autorelease];
}