Question

I have an mp3 file on a server. I want to get this file’s information like what’s the size of this file, what’s the artists name, what’s the album name, when was the file created, when was it modified, etc. I want all this information.

Is it possible to get this information without actually downloading the whole file? Using NSURLConnection or otherwise?

EDIT:

The following code doesn’t give me the required information, i.e. file created by, artist name, etc

    NSError *rerror = nil;
    NSURLResponse *response = nil;

    NSURL *url = [NSURL URLWithString:@"http://link.to.mp3"];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [request setHTTPMethod:@"HEAD"];

    NSData *result = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&rerror];
    NSString *resultString = [[[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding] autorelease];

    NSLog(@"URL: %@", url);
    NSLog(@"Request: %@", request);
    NSLog(@"Result (NSData): %@", result);
    NSLog(@"Result (NSString): %@", resultString);
    NSLog(@"Response: %@", response);
    NSLog(@"Error: %@", rerror);

    if ([response isMemberOfClass:[NSHTTPURLResponse class]]) {
        NSLog(@"AllHeaderFields: %@", [((NSHTTPURLResponse *)response) allHeaderFields]);
    }

The “AllHeaderFields” is:

AllHeaderFields: {
    "Cache-Control" = "max-age=0";
    Connection = "keep-alive";
    "Content-Encoding" = gzip;
    "Content-Type" = "text/plain; charset=ascii";
    Date = "Fri, 17 Feb 2012 12:44:59 GMT";
    Etag = 19202n;
    Pragma = public;
    Server = dbws;
    "x-robots-tag" = "noindex,nofollow";
}

Answer 1

Yes and no. Things like the file size and modification date often come as part of the HEAD response. But not always: with a lot of dynamic URLs, you won’t get all of the information.

As for the artist and album name, they’re part of the MP3’s ID3, which is contained inside the file, and so you won’t be able to get them with a HEAD request. Since the ID3 tag is typically at the beginning of a file, you could try to grab just that part and then read the ID3 tag. But you won’t be able to do it with NSURLConnection since it doesn’t support just fetching part of a file, so you’ll need to find a more low-level way of getting data by HTTP.