Authentication with WKWebView in Swift

In a simpler way:

Though this answer looks redundant but posting as this may help other naive developers (like me).

   func webView(_ webView: WKWebView, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        guard (webView.url?.host) != nil else {
            return
        }
        let authenticationMethod = challenge.protectionSpace.authenticationMethod
        if authenticationMethod == NSURLAuthenticationMethodDefault || authenticationMethod == NSURLAuthenticationMethodHTTPBasic || authenticationMethod == NSURLAuthenticationMethodHTTPDigest {
            let credential = URLCredential(user: userName, password: password, persistence: .none)
            completionHandler(.useCredential, credential)
        } else if authenticationMethod == NSURLAuthenticationMethodServerTrust {
            completionHandler(.performDefaultHandling, nil)
        } else {
            completionHandler(.cancelAuthenticationChallenge, nil)
        }
    }

Add the following line:

completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential, credential)

at the end of didReceiveAuthenticationChallenge solved the problem.

i am late to party but still this can be useful for someone.

To support auth challenge in WKWebview Swift 4, complete code as below

func webView(_ webView: WKWebView, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        guard let hostname = webView.url?.host else {
            return
        }

        let authenticationMethod = challenge.protectionSpace.authenticationMethod
        if authenticationMethod == NSURLAuthenticationMethodDefault || authenticationMethod == NSURLAuthenticationMethodHTTPBasic || authenticationMethod == NSURLAuthenticationMethodHTTPDigest {
            let av = UIAlertController(title: webView.title, message: String(format: "AUTH_CHALLENGE_REQUIRE_PASSWORD".localized, hostname), preferredStyle: .alert)
            av.addTextField(configurationHandler: { (textField) in
                textField.placeholder = "USER_ID".localized
            })
            av.addTextField(configurationHandler: { (textField) in
                textField.placeholder = "PASSWORD".localized
                textField.isSecureTextEntry = true
            })

            av.addAction(UIAlertAction(title: "BUTTON_OK".localized, style: .default, handler: { (action) in
                guard let userId = av.textFields?.first?.text else{
                    return
                }
                guard let password = av.textFields?.last?.text else {
                    return
                }
                let credential = URLCredential(user: userId, password: password, persistence: .none)
                completionHandler(.useCredential,credential)
            }))
            av.addAction(UIAlertAction(title: "BUTTON_CANCEL".localized, style: .cancel, handler: { _ in
                completionHandler(.cancelAuthenticationChallenge, nil);
            }))
            self.parentViewController?.present(av, animated: true, completion: nil)
        }else if authenticationMethod == NSURLAuthenticationMethodServerTrust{
            // needs this handling on iOS 9
            completionHandler(.performDefaultHandling, nil);
        }else{
            completionHandler(.cancelAuthenticationChallenge, nil);
        }
    }