[webview_flutter] Add a method for getting the user agent (#4472)

Aggregate PR for adding a method for retrieving the user agent. 

Internal: b/272582342

Author: bparrishMines

packages/webview_flutter/webview_flutter/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.3.0
+
+* Adds support to retrieve the user agent. See `WebViewController.getUserAgent`.
+
 ## 4.2.4
 
 * Adds pub topics to package metadata.

packages/webview_flutter/webview_flutter/example/integration_test/webview_flutter_test.dart

@@ -179,7 +179,7 @@ Future<void> main() async {
 
     await pageFinished.future;
 
-    final String customUserAgent = await _getUserAgent(controller);
+    final String? customUserAgent = await controller.getUserAgent();
     expect(customUserAgent, 'Custom_User_Agent1');
   });
 
@@ -876,22 +876,6 @@ String _webViewString(String value) {
   return '"$value"';
 }
 
-/// Returns the value used for the HTTP User-Agent: request header in subsequent HTTP requests.
-Future<String> _getUserAgent(WebViewController controller) async {
-  return _runJavascriptReturningResult(controller, 'navigator.userAgent;');
-}
-
-Future<String> _runJavascriptReturningResult(
-  WebViewController controller,
-  String js,
-) async {
-  if (defaultTargetPlatform == TargetPlatform.iOS) {
-    return await controller.runJavaScriptReturningResult(js) as String;
-  }
-  return jsonDecode(await controller.runJavaScriptReturningResult(js) as String)
-      as String;
-}
-
 class ResizableWebView extends StatefulWidget {
   const ResizableWebView({
     super.key,

packages/webview_flutter/webview_flutter/example/pubspec.yaml

@@ -17,8 +17,8 @@ dependencies:
     # The example app is bundled with the plugin so we use a path dependency on
     # the parent directory to use the current plugin's version.
     path: ../
-  webview_flutter_android: ^3.6.0
-  webview_flutter_wkwebview: ^3.4.0
+  webview_flutter_android: ^3.12.0
+  webview_flutter_wkwebview: ^3.9.0
 
 dev_dependencies:
   build_runner: ^2.1.5

packages/webview_flutter/webview_flutter/lib/src/webview_controller.dart

@@ -353,6 +353,11 @@ class WebViewController {
   Future<void> setUserAgent(String? userAgent) {
     return platform.setUserAgent(userAgent);
   }
+
+  /// Gets the value used for the HTTP `User-Agent:` request header.
+  Future<String?> getUserAgent() {
+    return platform.getUserAgent();
+  }
 }
 
 /// Permissions request when web content requests access to protected resources.

packages/webview_flutter/webview_flutter/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter
 description: A Flutter plugin that provides a WebView widget on Android and iOS.
 repository: https://github.com/flutter/packages/tree/main/packages/webview_flutter/webview_flutter
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 4.2.4
+version: 4.3.0
 
 environment:
   sdk: ">=2.19.0 <4.0.0"
@@ -20,7 +20,7 @@ dependencies:
   flutter:
     sdk: flutter
   webview_flutter_android: ^3.0.0
-  webview_flutter_platform_interface: ^2.3.0
+  webview_flutter_platform_interface: ^2.6.0
   webview_flutter_wkwebview: ^3.0.0
 
 dev_dependencies:

packages/webview_flutter/webview_flutter/test/legacy/webview_flutter_test.mocks.dart

@@ -1,7 +1,9 @@
-// Mocks generated by Mockito 5.4.0 from annotations
+// Mocks generated by Mockito 5.4.1 from annotations
 // in webview_flutter/test/legacy/webview_flutter_test.dart.
 // Do not manually edit this file.
 
+// @dart=2.19
+
 // ignore_for_file: no_leading_underscores_for_library_prefixes
 import 'dart:async' as _i9;
 

packages/webview_flutter/webview_flutter/test/navigation_delegate_test.mocks.dart

@@ -1,7 +1,9 @@
-// Mocks generated by Mockito 5.4.0 from annotations
+// Mocks generated by Mockito 5.4.1 from annotations
 // in webview_flutter/test/navigation_delegate_test.dart.
 // Do not manually edit this file.
 
+// @dart=2.19
+
 // ignore_for_file: no_leading_underscores_for_library_prefixes
 import 'dart:async' as _i8;
 
@@ -208,6 +210,16 @@ class MockPlatformNavigationDelegate extends _i1.Mock
         returnValueForMissingStub: _i8.Future<void>.value(),
       ) as _i8.Future<void>);
   @override
+  _i8.Future<void> setOnHttpError(_i3.HttpResponseErrorCallback? onHttpError) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #setOnHttpError,
+          [onHttpError],
+        ),
+        returnValue: _i8.Future<void>.value(),
+        returnValueForMissingStub: _i8.Future<void>.value(),
+      ) as _i8.Future<void>);
+  @override
   _i8.Future<void> setOnProgress(_i3.ProgressCallback? onProgress) =>
       (super.noSuchMethod(
         Invocation.method(

packages/webview_flutter/webview_flutter/test/webview_controller_test.dart

@@ -387,6 +387,23 @@ void main() {
     requestCallback(const TestPlatformWebViewPermissionRequest());
     expect(permissionRequestCallbackCalled, isTrue);
   });
+
+  test('getUserAgent', () async {
+    final MockPlatformWebViewController mockPlatformWebViewController =
+        MockPlatformWebViewController();
+
+    const String userAgent = 'str';
+
+    when(mockPlatformWebViewController.getUserAgent()).thenAnswer(
+      (_) => Future<String?>.value(userAgent),
+    );
+
+    final WebViewController webViewController = WebViewController.fromPlatform(
+      mockPlatformWebViewController,
+    );
+
+    await expectLater(webViewController.getUserAgent(), completion(userAgent));
+  });
 }
 
 class TestPlatformWebViewPermissionRequest

packages/webview_flutter/webview_flutter/test/webview_controller_test.mocks.dart

@@ -1,7 +1,9 @@
-// Mocks generated by Mockito 5.4.0 from annotations
+// Mocks generated by Mockito 5.4.1 from annotations
 // in webview_flutter/test/webview_controller_test.dart.
 // Do not manually edit this file.
 
+// @dart=2.19
+
 // ignore_for_file: no_leading_underscores_for_library_prefixes
 import 'dart:async' as _i5;
 import 'dart:ui' as _i3;
@@ -353,6 +355,25 @@ class MockPlatformWebViewController extends _i1.Mock
         returnValue: _i5.Future<void>.value(),
         returnValueForMissingStub: _i5.Future<void>.value(),
       ) as _i5.Future<void>);
+  @override
+  _i5.Future<String?> getUserAgent() => (super.noSuchMethod(
+        Invocation.method(
+          #getUserAgent,
+          [],
+        ),
+        returnValue: _i5.Future<String?>.value(),
+      ) as _i5.Future<String?>);
+  @override
+  _i5.Future<void> setOnConsoleMessage(
+          void Function(_i2.JavaScriptConsoleMessage)? onConsoleMessage) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #setOnConsoleMessage,
+          [onConsoleMessage],
+        ),
+        returnValue: _i5.Future<void>.value(),
+        returnValueForMissingStub: _i5.Future<void>.value(),
+      ) as _i5.Future<void>);
 }
 
 /// A class which mocks [PlatformNavigationDelegate].
@@ -405,6 +426,16 @@ class MockPlatformNavigationDelegate extends _i1.Mock
         returnValueForMissingStub: _i5.Future<void>.value(),
       ) as _i5.Future<void>);
   @override
+  _i5.Future<void> setOnHttpError(_i6.HttpResponseErrorCallback? onHttpError) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #setOnHttpError,
+          [onHttpError],
+        ),
+        returnValue: _i5.Future<void>.value(),
+        returnValueForMissingStub: _i5.Future<void>.value(),
+      ) as _i5.Future<void>);
+  @override
   _i5.Future<void> setOnProgress(_i6.ProgressCallback? onProgress) =>
       (super.noSuchMethod(
         Invocation.method(

packages/webview_flutter/webview_flutter/test/webview_cookie_manager_test.mocks.dart

@@ -1,7 +1,9 @@
-// Mocks generated by Mockito 5.4.0 from annotations
+// Mocks generated by Mockito 5.4.1 from annotations
 // in webview_flutter/test/webview_cookie_manager_test.dart.
 // Do not manually edit this file.
 
+// @dart=2.19
+
 // ignore_for_file: no_leading_underscores_for_library_prefixes
 import 'dart:async' as _i4;