public protocol ImageDownloadRequestModifier

Represents and wraps a method for modifying request before an image download request starts.

  • A method will be called just before the request being sent. This is the last chance you can modify the image download request. You can modify the request for some customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.

    Usually, you pass an ImageDownloadRequestModifier as the associated value of KingfisherOptionsInfoItem.requestModifier and use it as the options parameter in related methods.

    If you do nothing with the input request and return it as is, a downloading process will start with it.



    func modified(for request: URLRequest) -> URLRequest?



    The input request contains necessary information like url. This request is generated according to your resource url as a GET request.

    Return Value

    A modified version of request, which you wish to use for downloading an image. If nil returned, a KingfisherError.requestError with .emptyRequest as its reason will occur.