gistfile1.m

- (void)uploadImage:(UIImage*)image
{
  NSData *imageData = UIImageJPEGRepresentation(image, 0.6);
  
  // 1
  NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
  config.HTTPMaximumConnectionsPerHost = 1;
  [config setHTTPAdditionalHeaders:@{@"Authorization": [Dropbox apiAuthorizationHeader]}];
  
  // 2
  NSURLSession *upLoadSession = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil];
  
  // for now just create a random file name, dropbox will handle it if we overwrite a file and create a new name..
  NSURL *url = [Dropbox createPhotoUploadURL];
  
  NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
  [request setHTTPMethod:@"PUT"];
  
  // 3
  self.uploadTask = [upLoadSession uploadTaskWithRequest:request fromData:imageData];
  
  // 4
  self.uploadView.hidden = NO;
  [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
  
  // 5
  [_uploadTask resume];
}