gistfile1.m

@protocol KmlDownloaderProtocol <NSObject>

- (void) downloadFileFrom:(NSString*)urlString isAsyncDownload:(BOOL)isAsync;
- (NSURL*) urlForKmlFile;

@end

@interface KmlDownloader : NSObject <KmlDownloaderProtocol>



#pragma mark - Methods

+ (KmlDownloader*) sharedKmlDownloader;

- (NSURL*) urlForTestKmlFile;

@end



#import "KmlDownloader.h"

@interface KmlDownloader ()

@property (nonatomic, strong) NSString *nameOnDisk;
@property (nonatomic, strong) NSString *pathToKmlFileOnDisk;

@end

@implementation KmlDownloader

+ (KmlDownloader*) sharedKmlDownloader
{
    static KmlDownloader *sharedKmlDownloader;
 
    if (!sharedKmlDownloader)
    {
        sharedKmlDownloader = [[KmlDownloader alloc] init];
    }
    return sharedKmlDownloader;
}


- (instancetype) init
{
    if (self = [super init])
    {
        _nameOnDisk = @"SiteKmlFile.kml";
    }
    return self;
}

/**
    Downloads a file from the specified URL string. Can download async or sync.
 
    @param: urlString - The location of the file.
    @prarm: isAsync - The download method.
 */
- (void) downloadFileFrom:(NSString*)urlString isAsyncDownload:(BOOL)isAsync
{
    if ([urlString length] < 13) // http://a.b.co
    {
        return;
    }
    
    // Construct the file path.
    NSURL *url = [NSURL URLWithString:urlString];
    self.pathToKmlFileOnDisk = [self pathForFile:self.nameOnDisk];
    
    if (isAsync == YES)
    {
        // fetch async.
        NSURLRequest *request = [NSURLRequest requestWithURL:url];
        [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue currentQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
           
            if (connectionError == nil)
            {
                if([data writeToFile:self.pathToKmlFileOnDisk atomically:YES] == NO)
                {
                    NSLog(@"There was a problem saving the Kml file to disk!");
                }
            }
        }];
    }
    else
    {
        // Synchronous download of file.
        NSData *kmlData = [NSData dataWithContentsOfURL:url];
        
        if (kmlData)
        {
            if ([kmlData writeToFile:self.pathToKmlFileOnDisk atomically:YES] == NO)
            {
                NSLog(@"There was a problem saving the Kml file to disk!");
            }
        }
    }
}

/**
    Returns the path to the file on disk.
 
    @param: fileName - The name of the file.
 */
- (NSString*) pathForFile:(NSString*)fileName
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString  *documentsDirectory = [paths objectAtIndex:0];
    NSString  *filePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory, fileName];
    return filePath;
}

/**
    Returns the URL for the Kml file on disk.
 */
- (NSURL*) urlForKmlFile
{
    if (self.nameOnDisk)
    {
//        BOOL kmlFileExists = [[NSFileManager defaultManager] fileExistsAtPath:self.pathToKmlFileOnDisk];
        
        return [NSURL URLWithString:self.pathToKmlFileOnDisk];
    }
    else
    {
        return nil;
    }
}

/**
    Returns the path to the test KML file in the main bundle.
 */
- (NSURL*) urlForTestKmlFile
{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"example" ofType:@"kml"];
    NSURL *url = [NSURL fileURLWithPath:path];
    return url;
}

@end