URLSession delegate is not working on swift 4.2

Question

This code is working fine on Swift version 3, I'm not able to make it work on Swift 4

func rest() {
        let path = "https://localhost:8443/someservice"
        let request = NSMutableURLRequest(URL: NSURL(string: path)!)
        let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
        let session = NSURLSession(configuration: configuration, delegate: self, delegateQueue:NSOperationQueue.mainQueue())
        let task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
            let json:JSON = JSON(data: data!)
            if let c = json["content"].string {
                print(c)
            }
        })
        task.resume()
    }
func URLSession(session: NSURLSession, task: NSURLSessionTask, didReceiveChallenge challenge: NSURLAuthenticationChallenge, completionHandler: (NSURLSessionAuthChallengeDisposition, NSURLCredential?) -> Void) {
        completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential, NSURLCredential(forTrust: challenge.protectionSpace.serverTrust!))
    }

Answer 1

You may need latest syntax

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

Answer 2

Your Delegate method is right for below swift 4.0 version but it's wrong for swift 4.0 and higher.

Here is working code, You need to use like this.

class ViewController: UIViewController,URLSessionDelegate {

    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
         completionHandler(URLSession.AuthChallengeDisposition.useCredential, URLCredential(trust: challenge.protectionSpace.serverTrust!))
    }
}