iOS cannot parse KML / XML downloaded from server - ios

Question

A KML file I include in the project parses correctly whereas the same file downloaded from a server does not?!
I modified Apple's KML parsing example to parse a KML file. If I add the KML file directly into the Xcode project it parses correctly and displays it's polylines, annotations, etc. on the map as expected. But if I download the same KML file from my server, save it to disk and attempt to parse it, the parsing does not work. i.e. the parser does not find any elements to parse in the file so nothing is displayed on the map!
Firstly I have verified that the file downloads and saves to disk correctly. I checked the simulator's data (SimPholders is a handy tool for this) to get the file and compare it to the original one in case of corruption, no problem there, it downloads and saves correctly, no corruption.
I next checked the URL to the file I pass to the KML parser to ensure that it is correct and it was fine. I used NSFileManager fileExistsAtPath to determine this, the KML file is at the path I provide to the parser.
In the map view controller's viewDidLoad method I download the file from the server and pass it to the parser.
- (void)viewDidLoad
{
[super viewDidLoad];
[[KmlDownloader sharedKmlDownloader] downloadFileFrom:#"http://www.myserver.com/file.kml" isAsyncDownload:NO];
NSURL *kmlUrl = [[KmlDownloader sharedKmlDownloader] urlForKmlFile];
if (kmlUrl)
{
kmlParser = [[KMLParser alloc] initWithURL:kmlUrl];
[kmlParser parseKML];
}
// Add all of the MKOverlay objects parsed from the KML file to the map.
NSArray *overlays = [kmlParser overlays];
[map addOverlays:overlays];
// Add all of the MKAnnotation objects parsed from the KML file to the map.
NSArray *annotations = [kmlParser points];
[map addAnnotations:annotations];
// Some positioning code of the view port here
}
KmlDownloader as a reference can be found as a Gist here. Sorry the formatting was messing up too much to include inline, its a relatively small file though.
Any ideas why this may be happening? Many thanks.

Answer 1

Ok found the issue. It was to do with how I was accessing the file once downloaded. Once saved to disk I would send it's URL to the parser. The problem was I was using the incorrect NSURL method, I was originally using:
NSURL *fileUrl = [NSURL URLWithString:[self pathForFile:self.pathToKmlFileOnDisk]];
Whereas I should have been using:
NSURL *fileUrl = [[NSURL alloc] initFileURLWithPath:self.pathToKmlFileOnDisk];
Both are the same URL but the second one includes the "file:///" prefix. Once changed the parser would parse as expected.