RAC Extension for ReactiveCocoa

Kingfisher+RAC.swift

    import Kingfisher
    import ReactiveCocoa
    import enum Result.NoError

    extension KingfisherManager {
        func rac_retrieveImageWithURL(URL: NSURL,
                                  optionsInfo: KingfisherOptionsInfo?,
                                  progressBlock: DownloadProgressBlock?) -> SignalProducer<(image: UIImage?, cacheType: CacheType, imageURL: NSURL?), NSError> {
            return SignalProducer { observer, disposable in
                
                let imageTask = KingfisherManager.sharedManager.retrieveImageWithURL(URL, optionsInfo: optionsInfo, progressBlock: progressBlock) { (image, error, cacheType, imageURL) -> () in
                    if let error = error {
                        observer.sendFailed(error)
                    } else {
                        observer.sendNext(image: image, cacheType: cacheType, imageURL: imageURL)
                        observer.sendCompleted()
                    }
                }
                
                disposable.addDisposable {
                    imageTask.cancel()
                }
            }
        }
    }