🎉 Add support for ephemeral sessions (#64)

Co-authored-by: Nico Mexis <nico.mexis@kabelmail.de>
Co-authored-by: Matthew Smith <matthew.smith@apptreesoftware.com>

Co-authored-by: Nico Mexis <nico.mexis@kabelmail.de>
Co-authored-by: Matthew Smith <matthew.smith@apptreesoftware.com>

Author: 3 people

android/src/main/kotlin/com/linusu/flutter_web_auth/FlutterWebAuthPlugin.kt

@@ -28,13 +28,17 @@ class FlutterWebAuthPlugin(private val context: Context): MethodCallHandler {
         "authenticate" -> {
           val url = Uri.parse(call.argument("url"))
           val callbackUrlScheme = call.argument<String>("callbackUrlScheme")!!
+          val preferEphemeral = call.argument<Boolean>("preferEphemeral")!!
 
           callbacks[callbackUrlScheme] = resultCallback
 
           val intent = CustomTabsIntent.Builder().build()
           val keepAliveIntent = Intent(context, KeepAliveService::class.java)
 
           intent.intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP or Intent.FLAG_ACTIVITY_NEW_TASK)
+          if (preferEphemeral) {
+              intent.intent.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY)
+          }
           intent.intent.putExtra("android.support.customtabs.extra.KEEP_ALIVE", keepAliveIntent)
 
           intent.launchUrl(context, url)

ios/Classes/SwiftFlutterWebAuthPlugin.swift

@@ -14,6 +14,7 @@ public class SwiftFlutterWebAuthPlugin: NSObject, FlutterPlugin {
         if call.method == "authenticate" {
             let url = URL(string: (call.arguments as! Dictionary<String, AnyObject>)["url"] as! String)!
             let callbackURLScheme = (call.arguments as! Dictionary<String, AnyObject>)["callbackUrlScheme"] as! String
+            let preferEphemeral = (call.arguments as! Dictionary<String, AnyObject>)["preferEphemeral"] as! Bool
 
             var sessionToKeepAlive: Any? = nil // if we do not keep the session alive, it will get closed immediately while showing the dialog
             let completionHandler = { (url: URL?, err: Error?) in
@@ -26,7 +27,7 @@ public class SwiftFlutterWebAuthPlugin: NSObject, FlutterPlugin {
                             return
                         }
                     }
-                    
+
                     if #available(iOS 11, *) {
                         if case SFAuthenticationError.canceledLogin = err {
                             result(FlutterError(code: "CANCELED", message: "User canceled login", details: nil))
@@ -50,6 +51,7 @@ public class SwiftFlutterWebAuthPlugin: NSObject, FlutterPlugin {
                         return
                     }
 
+                    session.prefersEphemeralWebBrowserSession = preferEphemeral
                     session.presentationContextProvider = provider
                 }
 

lib/flutter_web_auth.dart

@@ -28,12 +28,14 @@ class FlutterWebAuth {
   /// The page pointed to by [url] will be loaded and displayed to the user. From the page, the user can authenticate herself and grant access to the app. On completion, the service will send a callback URL with an authentication token, and this URL will be result of the returned [Future].
   ///
   /// [callbackUrlScheme] should be a string specifying the scheme of the url that the page will redirect to upon successful authentication.
-  static Future<String> authenticate({required String url, required String callbackUrlScheme}) async {
+  /// [preferEphemeral] if this is specified as `true`, an ephemeral web browser session will be used where possible (`FLAG_ACTIVITY_NO_HISTORY` on Android, `prefersEphemeralWebBrowserSession` on iOS/macOS)
+  static Future<String> authenticate({required String url, required String callbackUrlScheme, bool? preferEphemeral}) async {
     WidgetsBinding.instance?.removeObserver(_resumedObserver); // safety measure so we never add this observer twice
     WidgetsBinding.instance?.addObserver(_resumedObserver);
     return await _channel.invokeMethod('authenticate', <String, dynamic>{
       'url': url,
       'callbackUrlScheme': callbackUrlScheme,
+      'preferEphemeral': preferEphemeral ?? false,
     }) as String;
   }