Swift 3 URLSession с URLCredential не работает

Я делаю URLSession, но для URL требуются учетные данные.

У меня есть весь этот метод здесь, который пытается сделать URLSession с URLCredentials:

func loginUser(_ username: String, password: String, completion: @escaping (_ result: Bool) -> Void)
    {
        //Create request URL as String

        let requestString = String(format:"%@", webservice) as String

        //Covert URL request string to URL

        guard let url = URL(string: requestString) else {
            print("Error: cannot create URL")
            return
        }

        //Convert URL to URLRequest

        let urlRequest = URLRequest(url: url)

        print(urlRequest)

        //Add the username and password to URLCredential

        credential = URLCredential(user:username, password:password, persistence: .forSession)

        //Setup the URLSessionConfiguration

        let config = URLSessionConfiguration.default

        //Setup the URLSession

        let session = URLSession(configuration: config, delegate: self, delegateQueue: nil)

        //Prepare the task to get data.

        let task = session.dataTask(with: urlRequest, completionHandler: { (data, response, error) in

            DispatchQueue.main.async(execute: {

                if(error == nil)
                {
                    completion(true)
                }
                else
                {
                    completion(false)
                }

            })

        })

        //Run the task to get data.

        task.resume()

    }

и вот мои методы URLSessionDelegate:

func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {

        if challenge.previousFailureCount > 0
        {
            completionHandler(Foundation.URLSession.AuthChallengeDisposition.cancelAuthenticationChallenge, nil)
        }
        else
        {
            completionHandler(Foundation.URLSession.AuthChallengeDisposition.useCredential, URLCredential(trust:challenge.protectionSpace.serverTrust!))
        }

    }

    /**
     Requests credentials from the delegate in response to an authentication request from the remote server.
     */

    func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {

        completionHandler(Foundation.URLSession.AuthChallengeDisposition.useCredential,credential)

    }

Я замечаю, когда я отлаживаю это в этом методе делегата:

func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {

        if challenge.previousFailureCount > 0
        {
            completionHandler(Foundation.URLSession.AuthChallengeDisposition.cancelAuthenticationChallenge, nil)
        }
        else
        {
            completionHandler(Foundation.URLSession.AuthChallengeDisposition.useCredential, URLCredential(trust:challenge.protectionSpace.serverTrust!))
        }

    }

Чтобы этот метод вызывался дважды и когда он во второй раз попадал в эту строку:

completionHandler(Foundation.URLSession.AuthChallengeDisposition.useCredential, URLCredential(trust:challenge.protectionSpace.serverTrust!))

Я получаю эту ошибку:

fatal error: unexpectedly found nil while unwrapping an Optional value

а затем мое приложение сработает! Как исправить эту ошибку?

Ответ 1

авария из-за challenge.protectionSpace.serverTrust равна нулю при попытке развернуть его.

вы должны распаковать serverTrust и обрабатывать его как ноль. я предполагаю, что когда serverTrust равно nil challenge.error имеет значение.

func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {

    if challenge.previousFailureCount > 0 {
        completionHandler(Foundation.URLSession.AuthChallengeDisposition.cancelAuthenticationChallenge, nil)
    } else if let serverTrust = challenge.protectionSpace.serverTrust {
        completionHandler(Foundation.URLSession.AuthChallengeDisposition.useCredential, URLCredential(trust: serverTrust))
    } else {
        print("unknown state. error: \(challenge.error)")
        // do something w/ completionHandler here
    }
}

Ответ 2

Вот синтаксис в соответствии с быстрым 3.

Сначала проверьте, в какой части введенного метода делегата

open func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Swift.Void){

    var disposition: URLSession.AuthChallengeDisposition = URLSession.AuthChallengeDisposition.performDefaultHandling

    var credential:URLCredential?

    if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust {
        credential = URLCredential(trust: challenge.protectionSpace.serverTrust!)

        if (credential != nil) {
            disposition = URLSession.AuthChallengeDisposition.useCredential
        }
        else{
            disposition = URLSession.AuthChallengeDisposition.performDefaultHandling
        }
    }
    else{
        disposition = URLSession.AuthChallengeDisposition.cancelAuthenticationChallenge
    }

    if (completionHandler != nil) {
        completionHandler(disposition, credential);
    }
}