是否可以缓存视频？ IOS – 斯威夫特

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
    }
}

此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
        }
    }