Question

I’m needing some help on how to retrieve the full URL from a short one.
For example: http://tinysong.com/HJ9h
If you click that link it will open a grooveshark url. How can i retrieve the original grooveshark url?
Thank you

Answer 1

Short URLs work by HTTP redirection. You can set up an NSURLConnection with a request with the short URL and set a delegate. In the delegate, implement the method:

- (NSURLRequest *)connection:(NSURLConnection *)connection willSendRequest:(NSURLRequest *)request redirectResponse:(NSURLResponse *)response;

If response is non-nil, it’s a redirect. You can examine the response. You can check if it’s actually an instance of NSHTTPURLResponse using -isKindOfClass: and then get additional data from it.

Also, you can examine the new request that NSURLConnection proposes. Its URL property will be the new URL to which the server redirected your connection request.

If you were redirected and you have reason to believe that you won’t be redirected further and that’s all you were interested in, you can cancel the connection request by invoking -cancel on the connection object.

---

Update. Here’s some sample code:

#import <Foundation/Foundation.h>

static BOOL stop;

@interface MyDelegate : NSObject
@end

@implementation MyDelegate

- (NSURLRequest *)connection:(NSURLConnection *)connection willSendRequest:(NSURLRequest *)request redirectResponse:(NSURLResponse *)response
{
    NSLog(@"request %@", request);
    NSLog(@"response %@", response);
    return response ? nil : request;
}

- (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"%s: error %@", __func__, error);
    stop = TRUE;
}

- (void) connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSLog(@"%s", __func__);
    stop = TRUE;
}

@end

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSURLRequest* req = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://tinysong.com/HJ9h"]];
    MyDelegate* del = [[MyDelegate alloc] init];
    [NSURLConnection connectionWithRequest:req delegate:del];
    while (!stop)
        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];

    [pool drain];
    return 0;
}

Produces this output:

request <NSURLRequest http://tinysong.com/HJ9h>
response (null)
request <NSURLRequest http://grooveshark.com/#!/s/~/3Xl6OQ?src=11>
response <NSHTTPURLResponse: 0x103500340>
-[MyDelegate connectionDidFinishLoading:]