add HttpRequestOptions.dontFollowRedirects (#3473)

This implements the option to have http.request() not follow server's 3xx redirection replies
but instead return the exact redirection code and headers.

* on iOS, it uses a different NSURLSession instance for non-following request,
  with a NSURLSessionTaskDelegate implementing URLSessinTaskWillPerformHTTPRedirection...

* on Android, it just passes the option on to org.nativescript.widgets.Async.Http;
  so this requires the respective commit in tns-core-modules-widgets to work

tns-core-modules/http/http-request.android.ts

@@ -155,6 +155,9 @@ function buildJavaOptions(options: http.HttpRequestOptions) {
     if (types.isNumber(options.timeout)) {
         javaOptions.timeout = options.timeout;
     }
+    if (types.isBoolean(options.dontFollowRedirects)) {
+        javaOptions.dontFollowRedirects = options.dontFollowRedirects;
+    }
 
     if (options.headers) {
         var arrayList = new java.util.ArrayList<org.nativescript.widgets.Async.Http.KeyValuePair>();

tns-core-modules/http/http-request.ios.ts

@@ -20,7 +20,28 @@ var USER_AGENT_HEADER = "User-Agent";
 var USER_AGENT = `Mozilla/5.0 (i${device}; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5355d Safari/8536.25`;
 var sessionConfig = getter(NSURLSessionConfiguration, NSURLSessionConfiguration.defaultSessionConfiguration);
 var queue = getter(NSOperationQueue, NSOperationQueue.mainQueue);
-var session = NSURLSession.sessionWithConfigurationDelegateDelegateQueue(sessionConfig, null, queue);
+
+class NSURLSessionTaskDelegateImpl extends NSObject implements NSURLSessionTaskDelegate {
+    public static ObjCProtocols = [NSURLSessionTaskDelegate];
+    public URLSessionTaskWillPerformHTTPRedirectionNewRequestCompletionHandler(session: NSURLSession, task: NSURLSessionTask, response: NSHTTPURLResponse, request: NSURLRequest, completionHandler: (p1: NSURLRequest) => void): void {
+        completionHandler(null);
+    }
+}
+var sessionTaskDelegateInstance: NSURLSessionTaskDelegateImpl = <NSURLSessionTaskDelegateImpl>NSURLSessionTaskDelegateImpl.new();
+
+var defaultSession;
+function ensureDefaultSession() {
+    if (!defaultSession) {
+        defaultSession = NSURLSession.sessionWithConfigurationDelegateDelegateQueue(sessionConfig, null, queue);
+    }
+}
+
+var sessionNotFollowingRedirects;
+function ensureSessionNotFollowingRedirects() {
+    if (!sessionNotFollowingRedirects) {
+        sessionNotFollowingRedirects = NSURLSession.sessionWithConfigurationDelegateDelegateQueue(sessionConfig, sessionTaskDelegateInstance, queue);
+    }
+}
 
 var imageSource: typeof imageSourceModule;
 function ensureImageSource() {
@@ -57,6 +78,15 @@ export function request(options: http.HttpRequestOptions): Promise<http.HttpResp
                 urlRequest.timeoutInterval = options.timeout / 1000;
             }
 
+            var session;
+            if (types.isBoolean(options.dontFollowRedirects) && options.dontFollowRedirects) {
+                ensureSessionNotFollowingRedirects();
+                session = sessionNotFollowingRedirects;
+            } else {
+                ensureDefaultSession();
+                session = defaultSession;
+            }
+
             var dataTask = session.dataTaskWithRequestCompletionHandler(urlRequest,
                 function (data: NSData, response: NSHTTPURLResponse, error: NSError) {
                     if (error) {

tns-core-modules/http/http.d.ts

@@ -89,6 +89,11 @@ declare module "http" {
      * Gets or sets the request timeout in milliseconds.
      */
     timeout?: number;
+
+    /**
+     * Gets or sets wether to *not* follow server's redirection responses.
+     */
+    dontFollowRedirects?: boolean;
   }
 
   /**

tns-platform-declarations/android/org.nativescript.widgets.d.ts

@@ -30,6 +30,7 @@
                         public timeout: number;
                         public screenWidth: number;
                         public screenHeight: number;
+                        public dontFollowRedirects: boolean;
                     }
 
                     export class RequestResult {