NSURLConnection to NSURLSession - swift

Question

I'm new to Swift and NSURLConnection & NSURLSession. I have this code, to load a webpage and this works. But I got this warning that NSURLConnection was deprecated in iOS 9.0, and I have to use NSURLSession.
This is my code:
var authenticated:Bool = false
var urlConnection:NSURLConnection!
func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
if !authenticated {
self.authenticated = false
self.urlConnection = NSURLConnection(request: request, delegate: self)!
urlConnection.start()
return false
}
return true
}
// We use this method is to accept an untrusted site which unfortunately we need to do, as our PVM servers are self signed.
func connection(connection: NSURLConnection, canAuthenticateAgainstProtectionSpace protectionSpace: NSURLProtectionSpace) -> Bool {
return (protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust)
}
func connection(connection: NSURLConnection, didReceiveAuthenticationChallenge challenge: NSURLAuthenticationChallenge) {
if challenge.previousFailureCount == 0 {
self.authenticated = true
let credential: NSURLCredential = NSURLCredential(forTrust: challenge.protectionSpace.serverTrust!
)
challenge.sender!.useCredential(credential, forAuthenticationChallenge: challenge)
}
else {
challenge.sender!.cancelAuthenticationChallenge(challenge)
}
}
func connection(connection: NSURLConnection, didReceiveResponse response: NSURLResponse) {
// remake a webview call now that authentication has passed ok.
self.authenticated = true
web.loadRequest(request)
// Cancel the URL connection otherwise we double up (webview + url connection, same url = no good!)
urlConnection.cancel()
}
This works. Now I want to 'convert' it to NSURLSession, but I can't seem to manage. Can somebody help me with this? I'm quite sure it's not so difficult for someone who can code very well.
I've tried several times to change to NSURLSession, but every time I've got this error: NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9813). And with NSURLConnection the problem is solved.
This is one of my attempts while using NSURLSession:
var authenticated:Bool = false
var urlSession:NSURLSession!
var urlSessionConfig:NSURLSessionConfiguration!
func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
if !authenticated {
self.authenticated = false
self.urlSessionConfig = NSURLSessionConfiguration.defaultSessionConfiguration()
self.urlSession = NSURLSession(configuration: self.urlSessionConfig, delegate: self, delegateQueue:NSOperationQueue.mainQueue())
let task = self.urlSession.dataTaskWithRequest(request){
(myData, myResponse, myError) -> Void in
if(myError == nil){
if(self.authenticated){
self.web.loadRequest(request)
}
}
}
task.resume()
return false
}
return true
}
func URLSession(session: NSURLSession, didReceiveChallenge challenge: NSURLAuthenticationChallenge, completionHandler: (NSURLSessionAuthChallengeDisposition, NSURLCredential?) -> Void) {
if(challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust){
if(challenge.protectionSpace.host == "mydomain.org"){
self.authenticated = true
let credential = NSURLCredential(forTrust: challenge.protectionSpace.serverTrust!)
completionHandler(NSURLSessionAuthChallengeDisposition.UseCredential,credential);
}
}
}

Answer 1

You don't have to use NSURLSession. Odds are, NSURLConnection will be in a semi-supported state until the end of time, given how broadly it is used.
With that said, I'm only going to say this once, so listen very carefully. Do not, under any circumstances, publicly ship either version of this code as written. Self-signed certificates are okay, as long as you check them properly. This code is not doing that, which makes them no better than HTTP.
If the data has to be kept secret, either use a real certificate or add code to validate the self-signed certificates properly.
If it isn't even slightly important to keep it secret, just use HTTP.
This document explains how to properly implement modified TLS chain validation by adding trust for a specific certificate:
https://developer.apple.com/library/mac/documentation/NetworkingInternet/Conceptual/NetworkingTopics/Articles/OverridingSSLChainValidationCorrectly.html
BTW, you're not doing anything with challenges in other protection spaces or for other hostnames. If you never call the completion handler, then tasks that request any other type of authentication will just hang around forever, in limbo, waiting for you to decide how to handle the authentication request. This is probably not what you want, though I doubt it is causing your problem unless you're behind a proxy. Your NSURLConnection code accepted challenges within a single protection space, so it probably didn't experience that problem (as much).
With that said, I don't see why this is failing with that error code unless there's something else wrong with the cert beyond being self-signed. Oh, and there's a missing underscore in the method declaration. I don't think that is important anymore, but I'm not certain. Be sure your delegate method is actually getting called.
You might also try setting the CFNETWORK_DIAGNOSTICS environment variable to 1 (or more) and see if that provides any further insight.