Identifying complete size of file when transfer is in progress - ios

Question

In my iphone app, I am displaying information of files added to documents directory, in a table view, as soon as those are added. For this I am using DirectoryWatcher class provided in one of the sample codes by apple.
Below is the block of code showing its use:
- (void)viewDidLoad
{
// start monitoring the document directory…
self.aDirectoryWatcher = [DirectoryWatcher watchFolderWithPath:[self applicationDocumentsDirectory] delegate:self];
// scan for existing documents
[self directoryDidChange:self.aDirectoryWatcher];
}
- (void)directoryDidChange:(DirectoryWatcher *)folderWatcher
{
[self reconcileData];
}
One of the information displayed in table view cell is- file size, which I am obtaining as below:
NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:[fileURL path] error:nil];
NSNumber * size = [fileAttributes objectForKey:NSFileSize];
Problem is-
When I am trying to add a large file, such as a movie file, then as
soon as transfer starts (copy or move operation) it invokes
directoryDidChange: immediately. It did not wait unless the transfer
is complete. So I always get size as 0.
In case of small sized files, such as images, it works fine.
Now I have two question:
Is there any way to know the complete size of file, which is in transfer state. eg. if message displayed is copying 30 MB of 100 MB, I want to get 100 MB?
Is there any alternative of DirectoryWatcher, which notifies only when file is completely added?
Please suggest.

Answer 1

You are currently looking to the file system, you should look into the response headers from your download requests.
For example when you use NSURLConnection to download the file, you can implement the delegate method connection:didReceiveResponse: and look into the response headers.
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
NSLog(#"Expected content length: %lld", httpResponse.expectedContentLength);
}
}
To get notified when it's finished you can implement connectionDidFinishLoading:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// Notify download success
}
and
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
// Notify error
}