title: Download a file / image with AFNetworking in iOS?
body: <p>I thought I had it figured out but I just can't get it to work.
  I have a method that is called on every URL in an array.
  This method have a URL of a picture that should be downloaded in specific path in a Application Support folder for offline use.
  But maybe I'm misinterpreting the methods in the AFNetwork library.
  My method looks like this:</p>
  
  <pre><code>- (void) downloadImageInBackground:(NSDictionary *)args{
  
    @autoreleasepool {
  
      NSString *photourl = [args objectForKey:@"photoUrl"];
      NSString *articleID = [args objectForKey:@"articleID"];
      NSString *guideName = [args objectForKey:@"guideName"];
      NSNumber *totalNumberOfImages = [args objectForKey:@"totalNumberOfImages"];
  
      NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:photourl]];
  
      AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
      operation.inputStream = [NSInputStream inputStreamWithURL:[NSURL URLWithString:photourl]];
  
      [operation setShouldExecuteAsBackgroundTaskWithExpirationHandler:^{
          DLog(@"PROBLEMS_AF");
      }];
      DLog(@"URL_PHOTOURL: %@", photourl);
      DLog(@"indexSet: %@", operation.hasAcceptableStatusCode); 
      [operation  response];
  
      NSData *data = [args objectForKey:@"data"];
  
      NSString *path;
      path = [NSMutableString stringWithFormat:@"%@/Library/Application Support/Guides", NSHomeDirectory()];
      path = [path stringByAppendingPathComponent:guideName];
      NSString *guidePath = path;
      path = [path stringByAppendingPathComponent:photourl];
  
      if ([[NSFileManager defaultManager] fileExistsAtPath:guidePath]){
          [[NSFileManager defaultManager] createFileAtPath:path
                                                  contents:data
                                                attributes:nil];
      }
  
      DLog(@"path: %@", path);
      operation.outputStream = [NSOutputStream outputStreamToFileAtPath:path append:NO];
      [operation start];
  
  
      DLog(@"isExecuting: %d",[operation isExecuting]);
      DLog(@"IS_FINISHED: %d",[operation isFinished]);
  
  
    }
  
  } 
  </code></pre>
  
  <p>PhotoURL is the direct link to the image that I want to download.</p>
  
  <p>Since this method is called for all the images, all logs is called several times, and seems to be correct.</p>