UIImageView with progress blocks

ui_image_view.rb

class UIImageView
  def af_imageRequestOperation
    @af_imageRequestOperation
  end

  def af_imageRequestOperation=(operation)
    @af_imageRequestOperation = operation
  end

  def set_image_with_url(url)
    set_image_with_url(url, placeholder: nil)
  end

  def set_image_with_url(url, placeholder: placeholder)
    request = NSMutableURLRequest.requestWithURL(url)
    request.addValue('image/*', forHTTPHeaderField: 'Accept')

    set_image_with_url_request(request, placeholder: placeholder, success: nil, failure: nil)
  end

  def set_image_with_url_request(request, placeholder: placeholder, success: success_callback, failure: failure_callback, progress: progress_callback)
    cancelImageRequestOperation

    cached_image = self.class.af_sharedImageCache.cachedImageForRequest(request)

    if cached_image
      self.af_imageRequestOperation = nil

      if success_callback
        success_callback.call(nil, nil, cached_image)
      else
        self.image = cached_image
      end
    else
      if placeholder
        self.image = placeholder
      end
    end

    operation = AFImageRequestOperation.alloc.initWithRequest(request)

    operation.setCompletionBlockWithSuccess(
      lambda { |operation, response|
        if request == af_imageRequestOperation.request
          self.af_imageRequestOperation = nil
        end

        if success_callback
          success_callback.call(operation.request, operation.response, response)
        end

        self.class.af_sharedImageCache.cacheImage(response, forRequest: request)
      }, failure: lambda { |operation, error|
        if request == self.af_imageRequestOperation.request
          self.af_imageRequestOperation = nil
        end

        if failure_callback
          failure_callback.call(operation.request, operation.response, error)
        end
      })

    if progress_callback
      operation.setDownloadProgressBlock(progress_callback)
    end

    self.af_imageRequestOperation = operation

    self.class.af_sharedImageRequestOperationQueue.addOperation(af_imageRequestOperation)
  end
end