Alamofire 请求已取消 (-999)

Question

我想使用 RequestAdapter 和 RequestRetrier 协议，所以我创建了自己的所谓 AuthenticationHandler 类，它实现了这两种协议。我这样做是因为刷新令牌可能已过期，因此此机制派上用场。RequestAdapter 协议方法adapt会被调用，但是should RequestRetrier 协议方法不会被调用。我有一个单独的类来执行实际请求：

class TestRequest {

var authHandler: AuthenticationHandler?

func executeRequest() {
    // For testing purposes a false access token is passed
    self.authHandler = AuthenticationHandler(accessToken: "some_default_token")

    let sessionManager = SessionManager()
    sessionManager.adapter = authHandler
    sessionManager.retrier = authHandler

    var loginModel : LoginMessage = LoginMessage.init()

    loginModel.username = "someUserName"
    loginModel.password = "WrongPassword"

    do {
        let binaryData = try loginModel.serializedData()

        // Create a file with this binary data in order to use it as part of the multipart formdata
        guard let fileURL = createFileFrom(data: binaryData) else {
            print("Error creating file")
            return
        }

        // Note: custom headers have been set in the AuthenticationHandler

        sessionManager.upload(multipartFormData: { multipartFormData in
            multipartFormData.append(fileURL, withName: "content")
        },
                              to: K.endpointLogin) { (encodingResult) in
                                switch encodingResult{
                                case .success(let upload, _, _):
                                    upload.responseJSON { response in
                                        print("Encoding result success...")
                                        print("Statuscode: \(response.response?.statusCode)")
                                        print(response)
                                    }
                                case .failure(let encodingError):
                                    print("Failure: \(encodingError)")
                                }
        }
    } catch {
        print(error)
    }       
}

我已按照此处文档中的示例进行操作

我读过几篇以前的帖子，说这与保留 sessionManager 有关。但我认为这也涵盖了。我的身份验证处理程序如下所示：

class AuthenticationHandler: RequestAdapter, RequestRetrier {

private typealias RefreshCompletion = (_ succeeded: Bool, _ accessToken: String?) -> Void

private let sessionManager: SessionManager = {
    let configuration = URLSessionConfiguration.default
    configuration.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders
    return SessionManager(configuration: configuration)
}()

private let lock = NSLock()

private var accessToken: String

private var isRefreshing = false
private var requestsToRetry: [RequestRetryCompletion] = []

init(accessToken: String) {
    self.accessToken = accessToken
}

// MARK: - RequestAdapter protocol method

func adapt(_ urlRequest: URLRequest) throws -> URLRequest {
    var urlRequest = urlRequest

    if let urlString = urlRequest.url?.absoluteString, urlString.hasPrefix(K.SERVER_URL) {
        urlRequest.setValue("application/json", forHTTPHeaderField: "Accept")
        urlRequest.setValue("multipart/form-data", forHTTPHeaderField: "Content-Type")
        urlRequest.setValue("Bearer " + accessToken, forHTTPHeaderField: "Authorization")
    }

    return urlRequest
}

// MARK: - RequestRetrier protocol method

func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: @escaping RequestRetryCompletion) {
    lock.lock() ; defer { lock.unlock() }
    }
}

我的配置如下：

• Alamofire 版本：4.7.2
• Xcode 版本：9.4.1
• 斯威夫特版本：4

我在这里做错了什么？为什么请求被取消并且没有调用should方法？任何帮助是极大的赞赏。

Answer 1

您的核心问题是您的SessionManager实例正在被deinit编辑，这会取消任何正在进行的任务。您应该将它保留在单例或类似的东西中，这将解决另一个问题，即为SessionManager每个请求使用一个 new 的问题，这是一种反模式。