ios - 如何将从 Internet 下载的数据保存到内部设备？

我有这个代码:

struct ServerConnect {
    enum Result<T> {
        case succes(T)
        case error(String)
    }

    typealias completionHandler = (Result<Data >) -> ()

    func getJsonFromServer(parameters: String, completion: @escaping completionHandler) {
        let fullUrlString = ApiConstans.fullPath + parameters
        guard let url = URL(string: fullUrlString) else {
            debugPrint("\(ErrorsLabels.ServerConnect01)")
            return completion(.error("\(ErrorsLabels.ServerConnect01)"))
        }

        URLSession.shared.dataTask(with: url) {  (data, response, error) in
            guard error == nil else {
                debugPrint("\(ErrorsLabels.ServerConnect02)")
                return completion(.error("\(ErrorsLabels.ServerConnect02)"))
            }

            guard let data = data else {
                debugPrint("\(ErrorsLabels.ServerConnect03)")
                return completion(.error("\(ErrorsLabels.ServerConnect03)"))
            }

            debugPrint("R> \(fullUrlString)")
            return completion(.succes(data))
            }.resume()
    }


    func getJsonProducts(lang: String?, region: Int?, completion: @escaping completionHandler) {
        self.getJsonFromServer(parameters: "?action=GET_PRODUCTS&lang=\(lang!)&region=\(region!)", completion: completion)
    }

}

我想将从互联网下载的数据保存在设备的内存中。

我正在尝试这段代码:

getJsonProducts(lang: selectedLanguage, region: selectedRegion , completion: { (data) in
                    print("@@@@@ \(data)")
                     saveJsonFileToTheDisk(path: selectedLanguage + "/json/products.json",  downloadData: data)
                })

func saveJsonFileToTheDisk(path: String, downloadData: Data){
        do {
            let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
            let fileURL = documentsURL.appendingPathComponent(path)
            try downloadData.write(to: fileURL, options: .atomic)
        } catch { }
    }

但不幸的是，它不起作用。我怎样才能让它发挥作用？

以下是错误:

Cannot convert value of type 'ServerConnect.Result' to expected argument type 'Data'

---

Best Answer-推荐答案

根据getJsonProducts方法的定义:

func getJsonProducts(lang: String?, region: Int?, completion: @escaping (Result<Data>) -> ()) {

发送到completion block 的参数data实际上是包含数据的Result类型，而不是数据本身。因此，您应该这样做:

getJsonProducts(lang: selectedLanguage, region: selectedRegion, completion: { result in
    switch result {
    case .succes(let data):
        saveJsonFileToTheDisk(path: selectedLanguage + "/json/products.json",  downloadData: data)
    case .error(let errorMessage):
        // Do something with the error message.
        break
    }
})

关于ios - 如何将从 Internet 下载的数据保存到内部设备？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/50445705/