使用Haneke，我无法检索缓存视频的文件路径。我通过将视频保存在缓存的目录中来处理它。

public enum Result<T> {
    case success(T)
    case failure(NSError)
}

class CacheManager {

    static let shared = CacheManager()

    private let fileManager = FileManager.default

    private lazy var mainDirectoryUrl: URL = {

        let documentsUrl = self.fileManager.urls(for: .cachesDirectory, in: .userDomainMask).first!
        return documentsUrl
    }()

    func getFileWith(stringUrl: String, completionHandler: @escaping (Result<URL>) -> Void ) {


        let file = directoryFor(stringUrl: stringUrl)

        //return file path if already exists in cache directory
        guard !fileManager.fileExists(atPath: file.path)  else {
            completionHandler(Result.success(file))
            return
        }

        DispatchQueue.global().async {

            if let videoData = NSData(contentsOf: URL(string: stringUrl)!) {                    
                videoData.write(to: file, atomically: true)

                DispatchQueue.main.async {
                    completionHandler(Result.success(file))
                }
            } else {
                DispatchQueue.main.async {
                    completionHandler(Result.failure(NSError.errorWith(text: "Can't download video")))
                }
            }
        }
    }

    private func directoryFor(stringUrl: String) -> URL {

        let fileURL = URL(string: stringUrl)!.lastPathComponent

        let file = self.mainDirectoryUrl.appendingPathComponent(fileURL)

        return file
    }
}

该类的示例用法如下所示：

CacheManager.shared.getFileWith(stringUrl: "http://techslides.com/demos/sample-videos/small.mp4") { result in

        switch result {
        case .success(let url):
             // do some magic with path to saved video                
        case .failure(let error):
            // handle errror
        }
    }