[desktop-webview-window] Control URL requests made by the webview (Breaking!) (#296)

* commit

* commit

* commit2

* revert main

* cleanup

* rename

* changes

* changes

* changes

* change how to set callback

* extend launch by a switch allowing to decide whether the OnUrlRequestEvent is to be triggered or not

Author: Iri-Hor

packages/desktop_webview_window/example/lib/main.dart

@@ -138,13 +138,15 @@ class _MyAppState extends State<MyApp> {
       ..setBrightness(Brightness.dark)
       ..setApplicationNameForUserAgent(" WebviewExample/1.0.0")
       ..launch(_controller.text)
-      ..addOnUrlRequestCallback((url) {
+      ..setOnUrlRequestCallback((url) {
         debugPrint('url: $url');
         final uri = Uri.parse(url);
         if (uri.path == '/login_success') {
           debugPrint('login success. token: ${uri.queryParameters['token']}');
           webview.close();
         }
+        // grant navigation request
+        return true;
       })
       ..onClose.whenComplete(() {
         debugPrint("on close");

packages/desktop_webview_window/lib/desktop_webview_window.dart

@@ -139,12 +139,12 @@ class WebviewWindow {
         break;
       case "onUrlRequested":
         final url = args['url'] as String;
-        webview.notifyUrlChanged(url);
+        final ret = webview.notifyUrlChanged(url);
         await _otherIsolateMessageHandler.invokeMethod('onUrlRequested', {
           'webViewId': viewId,
           'url': url,
         });
-        break;
+        return ret;
       case "onWebMessageReceived":
         final message = args['message'] as String;
         webview.notifyWebMessageReceived(message);

packages/desktop_webview_window/lib/src/webview.dart

@@ -10,7 +10,7 @@ typedef OnHistoryChangedCallback = void Function(
 
 /// Callback when WebView start to load a URL.
 /// [url] is the URL string.
-typedef OnUrlRequestCallback = void Function(String url);
+typedef OnUrlRequestCallback = bool Function(String url);
 
 /// Callback when WebView receives a web message
 /// [message] constains the webmessage
@@ -35,7 +35,7 @@ abstract class Webview {
   void setPromptHandler(PromptHandler? handler);
 
   /// Navigates to the given URL.
-  void launch(String url);
+  void launch(String url, {bool triggerOnUrlRequestEvent=true});
 
   /// change webview theme.
   ///
@@ -74,9 +74,7 @@ abstract class Webview {
   /// Register a callback that will be invoked when the webview history changes.
   void setOnHistoryChangedCallback(OnHistoryChangedCallback? callback);
 
-  void addOnUrlRequestCallback(OnUrlRequestCallback callback);
-
-  void removeOnUrlRequestCallback(OnUrlRequestCallback callback);
+  void setOnUrlRequestCallback(OnUrlRequestCallback? callback);
 
   void addOnWebMessageReceivedCallback(OnWebMessageReceivedCallback callback);
 

packages/desktop_webview_window/lib/src/webview_impl.dart

@@ -22,9 +22,9 @@ class WebviewImpl extends Webview {
 
   OnHistoryChangedCallback? _onHistoryChanged;
 
-  final ValueNotifier<bool> _isNaivgating = ValueNotifier<bool>(false);
+  final ValueNotifier<bool> _isNavigating = ValueNotifier<bool>(false);
 
-  final Set<OnUrlRequestCallback> _onUrlRequestCallbacks = {};
+  OnUrlRequestCallback? _onUrlRequestCallback = null;
 
   final Set<OnWebMessageReceivedCallback> _onWebMessageReceivedCallbacks = {};
 
@@ -57,12 +57,14 @@ class WebviewImpl extends Webview {
   }
 
   void onNavigationStarted() {
-    _isNaivgating.value = true;
+    _isNavigating.value = true;
   }
 
-  void notifyUrlChanged(String url) {
-    for (final callback in _onUrlRequestCallbacks) {
-      callback(url);
+  bool notifyUrlChanged(String url) {
+    if(_onUrlRequestCallback != null) {
+      return _onUrlRequestCallback!(url);
+    } else {
+      return true;
     }
   }
 
@@ -73,11 +75,11 @@ class WebviewImpl extends Webview {
   }
 
   void onNavigationCompleted() {
-    _isNaivgating.value = false;
+    _isNavigating.value = false;
   }
 
   @override
-  ValueListenable<bool> get isNavigating => _isNaivgating;
+  ValueListenable<bool> get isNavigating => _isNavigating;
 
   @override
   void registerJavaScriptMessageHandler(
@@ -121,10 +123,11 @@ class WebviewImpl extends Webview {
   }
 
   @override
-  void launch(String url) async {
+  void launch(String url, {bool triggerOnUrlRequestEvent=true}) async {
     await channel.invokeMethod("launch", {
       "url": url,
       "viewId": viewId,
+      "triggerOnUrlRequestEvent": triggerOnUrlRequestEvent,
     });
   }
 
@@ -223,13 +226,8 @@ class WebviewImpl extends Webview {
   }
 
   @override
-  void addOnUrlRequestCallback(OnUrlRequestCallback callback) {
-    _onUrlRequestCallbacks.add(callback);
-  }
-
-  @override
-  void removeOnUrlRequestCallback(OnUrlRequestCallback callback) {
-    _onUrlRequestCallbacks.remove(callback);
+  void setOnUrlRequestCallback(OnUrlRequestCallback? callback) {
+    _onUrlRequestCallback = callback;
   }
 
   @override

packages/desktop_webview_window/windows/web_view.cc

@@ -8,6 +8,8 @@
 #include <utility>
 #include <thread>
 
+#include "flutter/method_result_functions.h"
+
 #include "web_view.h"
 #include "utils.h"
 #include "strconv.h"
@@ -144,14 +146,34 @@ void WebView::OnWebviewControllerCreated() {
                 std::make_unique<flutter::EncodableValue>(flutter::EncodableMap{
                     {flutter::EncodableValue("id"), flutter::EncodableValue(web_view_id_)},
                 }));
-            LPWSTR uri;
-            args->get_Uri(&uri);
-            method_channel_->InvokeMethod(
-                "onUrlRequested",
-                std::make_unique<flutter::EncodableValue>(flutter::EncodableMap{
-                    {flutter::EncodableValue("id"), flutter::EncodableValue(web_view_id_)},
-                    {flutter::EncodableValue("url"), flutter::EncodableValue(wide_to_utf8(std::wstring(uri)))},
-                }));
+
+            if (triggerOnUrlRequestedEvent) {
+              LPWSTR uri;
+              args->get_Uri(&uri);
+
+              auto result_handler = std::make_unique<flutter::MethodResultFunctions<>>(
+                  [uri, sender, this](const flutter::EncodableValue* success_value) {
+                  const bool letPass = std::get<bool>(*success_value);
+                    if (letPass) {
+                      this->setTriggerOnUrlRequestedEvent(false);
+                      sender->Navigate(uri);
+                    }
+                  },
+                  nullptr, nullptr);
+
+              method_channel_->InvokeMethod(
+                  "onUrlRequested",
+                  std::make_unique<flutter::EncodableValue>(flutter::EncodableMap{
+                      {flutter::EncodableValue("id"), flutter::EncodableValue(web_view_id_)},
+                      {flutter::EncodableValue("url"), flutter::EncodableValue(wide_to_utf8(std::wstring(uri)))},
+                  }), std::move(result_handler));
+
+              // navigation is canceled here and retriggered later from the callback passed to the method channel
+              args->put_Cancel(true);
+            } else {
+              args->put_Cancel(false);
+              triggerOnUrlRequestedEvent = true;
+            }
             return S_OK;
           }
       ).Get(), nullptr);
@@ -323,6 +345,10 @@ void WebView::PostWebMessageAsJson(const std::wstring& webmessage,
   }
 }
 
+void WebView::setTriggerOnUrlRequestedEvent(const bool value) {
+  this->triggerOnUrlRequestedEvent = value;
+}
+
 WebView::~WebView() {
   if (webview_) {
     webview_->Stop();

packages/desktop_webview_window/windows/web_view.h

@@ -60,6 +60,8 @@ class WebView {
   void PostWebMessageAsJson(const std::wstring &webmessage,
       std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> completer);
 
+  void setTriggerOnUrlRequestedEvent(const bool value);
+
  private:
   wil::unique_hwnd view_window_;
 
@@ -79,6 +81,8 @@ class WebView {
 
   std::wstring user_data_folder_;
 
+  bool triggerOnUrlRequestedEvent{true};
+
   void OnWebviewControllerCreated();
 
   [[nodiscard]] bool CanGoBack() const;

packages/desktop_webview_window/windows/web_view_window_plugin.cc

@@ -86,6 +86,7 @@ void WebviewWindowPlugin::HandleMethodCall(
 
     auto window_id = arguments->at(flutter::EncodableValue("viewId")).LongValue();
     auto url = std::get<std::string>(arguments->at(flutter::EncodableValue("url")));
+    auto triggerOnUrlRequestEvent = std::get<bool>(arguments->at(flutter::EncodableValue("triggerOnUrlRequestEvent")));
 
     if (!windows_.count(window_id)) {
       result->Error("0", "can not find webview window for id");
@@ -95,6 +96,7 @@ void WebviewWindowPlugin::HandleMethodCall(
       result->Error("0", "webview window not ready");
       return;
     }
+    windows_[window_id]->GetWebView()->setTriggerOnUrlRequestedEvent(triggerOnUrlRequestEvent);
     windows_[window_id]->GetWebView()->Navigate(utf8_to_wide(url));
     result->Success();
   } else if (method_call.method_name() == "addScriptToExecuteOnDocumentCreated") {