Swift 2 nil NSURLSessionDataTask when adding configuration - ios

Question

When session is set as .init(configuration:..., delegate:self, delegateQueue:NSOperationQueue.mainQueue()) for proxy server redirect, NSURLSessionDataTask.resume() does not result in execution of task. When session is set as .sharedSession(), task executes as expected.
**kCFStreamPropertyHTTPProxyHost etc. have been deprecated. Maybe this affects NSURLSessionConfiguration in a way that prevents execution of task?
class ConnectionManager: NSURLSession, NSURLSessionDelegate {
.
.
.
if shouldUseProxy {
let proxyEnable = NSNumber(int: 1) as CFNumber
let proxyDict: [NSObject:AnyObject] = [
kCFNetworkProxiesHTTPEnable: proxyEnable,
kCFStreamPropertyHTTPProxyHost: proxyHost,
kCFStreamPropertyHTTPProxyPort: proxyPort,
kCFStreamPropertyHTTPSProxyHost: proxyHost,
kCFStreamPropertyHTTPSProxyPort: proxyPort,
kCFProxyTypeKey: kCFProxyTypeHTTPS,
kCFProxyUsernameKey: proxyUser,
kCFProxyPasswordKey: proxyPW
]
let config = NSURLSessionConfiguration.ephemeralSessionConfiguration()
config.connectionProxyDictionary = proxyDict
self.session = NSURLSession.init(configuration: config, delegate: self, delegateQueue: NSOperationQueue.mainQueue())
} else {
self.session = NSURLSession.sharedSession()
}
self.task = self.session.dataTaskWithRequest(request) {
(data, response, error) in
if error == nil {
self.cookies = NSHTTPCookieStorage.sharedHTTPCookieStorage().cookiesForURL(response!.URL!)!
self.httpResponse = (response as? NSHTTPURLResponse)!
self.statusCode = (self.httpResponse!.statusCode)
guard error == nil && data != nil else {
print(error)
return
}
do {
if self.statusCode == 200 {
self.contentsOfURL = try NSString(contentsOfURL: self.URL, encoding: NSUTF8StringEncoding) as String
}
} catch {
}
}
}
self.task?.resume()
.
.
.
}

Answer 1

Setting the configuration
In most cases the default configuration works unless you need something special.
let sessionConfiguration = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: sessionConfiguration,
delegate: self,
delegateQueue: operationQueue)
Pls refer Apple's documentation: https://developer.apple.com/library/ios/documentation/Foundation/Reference/NSURLSession_class/#//apple_ref/doc/uid/TP40013435-CH1-SW7
Redirect response
NSURLSessionDelegate has the below mentioned function which gets called when a redirect happens.
func URLSession(session: NSURLSession, task: NSURLSessionTask, willPerformHTTPRedirection response: NSHTTPURLResponse, newRequest request: NSURLRequest, completionHandler: (NSURLRequest?) -> Void) {
//self.completionHandler is some completion handler you have defined, it is call back function.
if cancelled {
self.completionHandler(nil, redirectRequest:nil, wasCancelled: true)
}
else {
self.completionHandler(nil, redirectRequest:request, wasCancelled: false)
}
finished = true
executing = false
}
There is a parameter called request which contains the new URLRequest. Now you have to initiate a new session task with this new request
Challenge
This function is part of NSURLSessionDelegate
Whenever challenge is received the following function is called. Depending on the type of challenge, you have to handle it appropriately.
See the commented out code for NSURLAuthenticationMethodHTTPBasic and NSURLAuthenticationMethodHTTPDigest
func URLSession(session: NSURLSession,
didReceiveChallenge challenge: NSURLAuthenticationChallenge,
completionHandler: (NSURLSessionAuthChallengeDisposition, NSURLCredential?) -> Void) {
print("Challenge:")
if(challenge.previousFailureCount == 0) {
let credential = credentialForChallenge(challenge)
print("Use Credential ....\n")
completionHandler(.UseCredential, credential)
}
else {
print("Previous Failure Count = \(challenge.previousFailureCount)")
print("Cancelling Challenge\n")
challenge.sender?.cancelAuthenticationChallenge(challenge)
}
}
//Custom method to get the credential for the challenge
//In your case you would be interested in NSURLAuthenticationMethodHTTPBasic
func credentialForChallenge(challenge : NSURLAuthenticationChallenge) -> NSURLCredential? {
//https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/URLLoadingSystem/Articles/AuthenticationChallenges.html
//challenge knows:
//what triggered the challenge
//how many attempts were made for the challenge - previousFailureCount
//any previous attempted credentials - proposedCredential
//the NSURLProtectionSpace that requires the credentials
//sender of the challenge
//#Respond
//Get authentication method
let credential : NSURLCredential?
print("Method = \(challenge.protectionSpace.authenticationMethod)")
switch(challenge.protectionSpace.authenticationMethod) {
case NSURLAuthenticationMethodHTTPBasic:
// HTTP basic authentication
// prompt user for username and password
// let credential = NSURLCredential(user: <#T##String#>, password: <#T##String#>, persistence: <#T##NSURLCredentialPersistence#>)
credential = nil
case NSURLAuthenticationMethodHTTPDigest:
// HTTP digest authentication
// prompt user for username and password
// let credential = NSURLCredential(user: <#T##String#>, password: <#T##String#>, persistence: <#T##NSURLCredentialPersistence#>)
credential = nil
case NSURLAuthenticationMethodClientCertificate:
// Client certificate authentication
// let credential = NSURLCredential(identity: <#T##SecIdentity#>, certificates: <#T##[AnyObject]?#>, persistence: <#T##NSURLCredentialPersistence#>)
credential = nil
case NSURLAuthenticationMethodServerTrust:
// Server trust authentication
if let serverTrustExists = challenge.protectionSpace.serverTrust {
credential = NSURLCredential(trust: serverTrustExists)
}
else {
credential = nil
}
default:
credential = nil
}
return credential
}