Download ePub (NSURLConnection), save it, and open it with UIDocumentInteractionController - objective-c

Question

So I am trying to download an ePub book with NSURLConnection. So far, the download is working perfectly. The issue comes when I try to save it and open it. When I try to open it with UIDocumentInteractionController, the app crashes saying that the directory is null.
Here is my code:
//Download ePub file
NSURL *url = [NSURL URLWithString:#"http://www.terceiroanjo.com/materiais/missaopiloto.epub"];
NSURLRequest *theRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:10.0];
connection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
then
// save it ("data" = NSMutableData that was appended from the received data of the download)
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSString *filePath = [NSString stringWithFormat:#"%u/%#", NSDocumentDirectory,#"missaopiloto.epub"];
[data writeToFile:filePath atomically:YES];
}
and to open the ePub:
NSString *path = [[NSBundle mainBundle] pathForResource:#"missaopiloto" ofType:#"epub"];
NSURL *urls = [NSURL fileURLWithPath:path];
self.documentController = [UIDocumentInteractionController interactionControllerWithURL:urls];
documentController.delegate = self;
[documentController presentOpenInMenuFromRect:CGRectZero inView:self.view animated:YES];
When I try to open it, the app crashes:
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[NSURL initFileURLWithPath:]: nil string parameter'
I get it, the directory is nill, but why? What am I doing wrong. Any ideas?
Thanks.

Answer 1

I think the problem here is that, once you download and save a file, it's not becoming part of the bundle.
If you want to access the file you must provide the local path and create the local URL
NSString *path = [NSString stringWithFormat:#"%u/%#", NSDocumentDirectory,#"missaopiloto.epub"];
NSURL *urls = [NSURL fileURLWithPath:path];
self.documentController = [UIDocumentInteractionController interactionControllerWithURL:urls];
documentController.delegate = self;
[documentController presentOpenInMenuFromRect:CGRectZero inView:self.view animated:YES];