The easiest way to write NSData to a file

Question

NSData *data;
data = [self fillInSomeStrangeBytes];

My question is now how I can write this data on the easiest way to an file.

Answer 1

Notice that writing NSData into a file is an IO operation that may block the main thread. Especially if the data object is large.

Therefore it is advised to perform this on a background thread, the easiest way would be to use GCD as follows:

// Use GCD's background queue
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
    // Generate the file path
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"yourfilename.dat"];

     // Save it into file system
    [data writeToFile:dataPath atomically:YES];
});