Uploading an mp3 to my (php based) web server from an iPhone app

I'm looking to upload an mp3 file from my iPhone app to a given php page. To do this I found the ASIFormDataRequest class. Now I made a piece of code in my app like so:

NSLog(@"fastBackwardButtonLoosened - sending the stuff");
NSString *theUrl = @"MyServerURL";//Sorry not showing this:)
ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:theUrl]];

[request setFile:[soundFileURL absoluteString] forKey:@"mainfile"];
[request startSynchronous];
NSLog(@"The request was sent!!");

However I can't figure out how to put my NSURL which points to the mp3 inside this request. I have tried the above, but couldn't find anything that points me in the right direction.. Any ideas?

The code that receives the request is like so:

$SafeFile = $HTTP_POST_FILES['mainfile']['name'];
$uploaddir = "uploads/";
$path = $uploaddir.$SafeFile;

if($mainfile != none){ //AS LONG AS A FILE WAS SELECTED...

    if(copy($HTTP_POST_FILES['mainfile']['tmp_name'], $path)){ //IF IT HAS BEEN COPIED...
        //Good
    } else {
        //Bad开发者_如何学Python
    }
}

Here:

[request setFile:[soundFileURL absoluteString] forKey:@"mainfile"];

I think you should use [soundFileURL path] instead of [soundFileURL absoluteString], as [request setFile:] expects a filepath, not a full URL.