[webview_flutter] Fix platform exception on iOS 14+ when evaluating any JavaScript that evaluates to null or undefined.

packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.0.14
+
+* Fixed platform exception being thrown on iOS 14+ when evaluating any JavaScript evaluating to null or undefined.
+
 ## 2.0.13
 
 * Extract WKWebView implementation from `webview_flutter`.

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FLTWebViewTests.m

@@ -88,4 +88,129 @@ - (void)testContentInsetsSumAlwaysZeroAfterSetFrame {
   }
 }
 
+- (void)testEvaluateJavaScriptShouldCallCallAsyncJavaScriptIOS14AndAbove {
+  if (@available(iOS 14, *)) {
+    // Setup
+    FLTWebViewController *controller =
+        [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                     viewIdentifier:1
+                                          arguments:nil
+                                    binaryMessenger:self.mockBinaryMessenger];
+    FLTWKWebView *mockView = OCMClassMock(FLTWKWebView.class);
+    [OCMStub([mockView callAsyncJavaScript:[OCMArg any]
+                                 arguments:[OCMArg any]
+                                   inFrame:[OCMArg any]
+                            inContentWorld:[OCMArg any]
+                         completionHandler:[OCMArg any]]) andDo:^(NSInvocation *invocation) {
+      // __unsafe_unretained: https://github.com/erikdoe/ocmock/issues/384#issuecomment-589376668
+      __unsafe_unretained void (^evalResultHandler)(id, NSError *);
+      [invocation getArgument:&evalResultHandler atIndex:6];
+      evalResultHandler(@"RESULT", nil);
+    }];
+    controller.webView = mockView;
+    XCTestExpectation *resultExpectation = [self
+        expectationWithDescription:@"Should return successful result over the method channel."];
+
+    // Run
+    [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"evaluateJavascript"
+                                                               arguments:@"console.log('test')"]
+                      result:^(id _Nullable result) {
+                        XCTAssertTrue([@"RESULT" isEqualToString:result]);
+                        [resultExpectation fulfill];
+                      }];
+
+    // Verify
+    OCMVerify([mockView
+        callAsyncJavaScript:[OCMArg isEqual:@"return eval(\"console.log('test')\");"]
+                  arguments:[OCMArg any]
+                    inFrame:[OCMArg any]
+             inContentWorld:[OCMArg any]
+          completionHandler:[OCMArg any]]);
+    OCMReject([mockView evaluateJavaScript:[OCMArg any] completionHandler:[OCMArg any]]);
+    [self waitForExpectationsWithTimeout:30.0 handler:nil];
+  }
+}
+
+- (void)testEvaluateJavaScriptShouldCallEvaluateJavaScriptBelowIOS14 {
+  if (@available(iOS 14, *)) {
+  } else {
+    // Setup
+    FLTWebViewController *controller =
+        [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                     viewIdentifier:1
+                                          arguments:nil
+                                    binaryMessenger:self.mockBinaryMessenger];
+    FLTWKWebView *mockView = OCMClassMock(FLTWKWebView.class);
+    [OCMStub([mockView evaluateJavaScript:[OCMArg any]
+                        completionHandler:[OCMArg any]]) andDo:^(NSInvocation *invocation) {
+      // __unsafe_unretained: https://github.com/erikdoe/ocmock/issues/384#issuecomment-589376668
+      __unsafe_unretained void (^evalResultHandler)(id, NSError *);
+      [invocation getArgument:&evalResultHandler atIndex:3];
+      evalResultHandler(@"RESULT", nil);
+    }];
+    controller.webView = mockView;
+    XCTestExpectation *resultExpectation = [self
+        expectationWithDescription:@"Should return successful result over the method channel."];
+
+    // Run
+    [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"evaluateJavascript"
+                                                               arguments:@"console.log('test')"]
+                      result:^(id _Nullable result) {
+                        XCTAssertTrue([@"RESULT" isEqualToString:result]);
+                        [resultExpectation fulfill];
+                      }];
+
+    // Verify
+    OCMVerify([mockView evaluateJavaScript:@"console.log('test')" completionHandler:[OCMArg any]]);
+    [self waitForExpectationsWithTimeout:30.0 handler:nil];
+  }
+}
+
+- (void)testEvaluateJavaScriptShouldSendErrorResultOnError {
+  // Setup
+  FLTWebViewController *controller =
+      [[FLTWebViewController alloc] initWithFrame:CGRectMake(0, 0, 300, 400)
+                                   viewIdentifier:1
+                                        arguments:nil
+                                  binaryMessenger:self.mockBinaryMessenger];
+  NSError *testError = [NSError errorWithDomain:@""
+                                           code:1
+                                       userInfo:@{NSLocalizedDescriptionKey : @"Test Error"}];
+  FLTWKWebView *mockView = OCMClassMock(FLTWKWebView.class);
+  XCTestExpectation *resultExpectation =
+      [self expectationWithDescription:@"Should return error result over the method channel."];
+  if (@available(iOS 14, *)) {
+    [OCMStub([mockView callAsyncJavaScript:[OCMArg any]
+                                 arguments:[OCMArg any]
+                                   inFrame:[OCMArg any]
+                            inContentWorld:[OCMArg any]
+                         completionHandler:[OCMArg any]]) andDo:^(NSInvocation *invocation) {
+      // __unsafe_unretained: https://github.com/erikdoe/ocmock/issues/384#issuecomment-589376668
+      __unsafe_unretained void (^evalResultHandler)(id, NSError *);
+      [invocation getArgument:&evalResultHandler atIndex:6];
+      evalResultHandler(nil, testError);
+    }];
+  } else {
+    [OCMStub([mockView evaluateJavaScript:[OCMArg any]
+                        completionHandler:[OCMArg any]]) andDo:^(NSInvocation *invocation) {
+      // __unsafe_unretained: https://github.com/erikdoe/ocmock/issues/384#issuecomment-589376668
+      __unsafe_unretained void (^evalResultHandler)(id, NSError *);
+      [invocation getArgument:&evalResultHandler atIndex:3];
+      evalResultHandler(nil, testError);
+    }];
+  }
+  controller.webView = mockView;
+
+  // Run
+  [controller onMethodCall:[FlutterMethodCall methodCallWithMethodName:@"evaluateJavascript"
+                                                             arguments:@"console.log('test')"]
+                    result:^(id _Nullable result) {
+                      XCTAssertTrue([result class] == [FlutterError class]);
+                      [resultExpectation fulfill];
+                    }];
+
+  // Verify
+  [self waitForExpectationsWithTimeout:30.0 handler:nil];
+}
+
 @end

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.h

@@ -7,26 +7,30 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+/**
+ * The WkWebView used for the plugin.
+ *
+ * This class overrides some methods in `WKWebView` to serve the needs for the plugin.
+ */
+@interface FLTWKWebView : WKWebView
+@end
+
 @interface FLTWebViewController : NSObject <FlutterPlatformView, WKUIDelegate>
 
+@property(nonatomic) FLTWKWebView* webView;
+
 - (instancetype)initWithFrame:(CGRect)frame
                viewIdentifier:(int64_t)viewId
                     arguments:(id _Nullable)args
               binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger;
 
 - (UIView*)view;
+
+- (void)onMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result;
 @end
 
 @interface FLTWebViewFactory : NSObject <FlutterPlatformViewFactory>
 - (instancetype)initWithMessenger:(NSObject<FlutterBinaryMessenger>*)messenger;
 @end
 
-/**
- * The WkWebView used for the plugin.
- *
- * This class overrides some methods in `WKWebView` to serve the needs for the plugin.
- */
-@interface FLTWKWebView : WKWebView
-@end
-
 NS_ASSUME_NONNULL_END

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FlutterWebView.m

@@ -222,6 +222,14 @@ - (void)onCurrentUrl:(FlutterMethodCall*)call result:(FlutterResult)result {
   result(_currentUrl);
 }
 
+- (NSString*)escapeStringForJavaScript:(NSString*)string {
+  NSArray* arrayForEncoding = @[ string ];
+  NSString* jsonString = [[NSString alloc]
+      initWithData:[NSJSONSerialization dataWithJSONObject:arrayForEncoding options:0 error:nil]
+          encoding:NSUTF8StringEncoding];
+  return [jsonString substringWithRange:NSMakeRange(2, jsonString.length - 4)];
+}
+
 - (void)onEvaluateJavaScript:(FlutterMethodCall*)call result:(FlutterResult)result {
   NSString* jsString = [call arguments];
   if (!jsString) {
@@ -230,18 +238,31 @@ - (void)onEvaluateJavaScript:(FlutterMethodCall*)call result:(FlutterResult)resu
                                details:nil]);
     return;
   }
-  [_webView evaluateJavaScript:jsString
-             completionHandler:^(_Nullable id evaluateResult, NSError* _Nullable error) {
-               if (error) {
-                 result([FlutterError
-                     errorWithCode:@"evaluateJavaScript_failed"
-                           message:@"Failed evaluating JavaScript"
-                           details:[NSString stringWithFormat:@"JavaScript string was: '%@'\n%@",
-                                                              jsString, error]]);
-               } else {
-                 result([NSString stringWithFormat:@"%@", evaluateResult]);
-               }
-             }];
+  void (^evalResultHandler)(id, NSError*) = ^(_Nullable id evaluateResult,
+                                              NSError* _Nullable error) {
+    if (error) {
+      result([FlutterError
+          errorWithCode:@"evaluateJavaScript_failed"
+                message:@"Failed evaluating JavaScript"
+                details:[NSString
+                            stringWithFormat:@"JavaScript string was: '%@'\n%@", jsString, error]]);
+    } else if (evaluateResult == /*null*/ [NSNull null] || evaluateResult == /*undefined*/ nil) {
+      result(@"null");
+    } else {
+      result([NSString stringWithFormat:@"%@", evaluateResult]);
+    }
+  };
+  if (@available(iOS 14, *)) {
+    jsString = [NSString
+        stringWithFormat:@"return eval(\"%@\");", [self escapeStringForJavaScript:jsString]];
+    [_webView callAsyncJavaScript:jsString
+                        arguments:nil
+                          inFrame:nil
+                   inContentWorld:WKContentWorld.pageWorld
+                completionHandler:evalResultHandler];
+  } else {
+    [_webView evaluateJavaScript:jsString completionHandler:evalResultHandler];
+  }
 }
 
 - (void)onAddJavaScriptChannels:(FlutterMethodCall*)call result:(FlutterResult)result {

packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_wkwebview
 description: A Flutter plugin that provides a WebView widget based on Apple's WKWebView control.
 repository: https://github.com/flutter/plugins/tree/master/packages/webview_flutter/webview_flutter_wkwebview
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 2.0.13
+version: 2.0.14
 
 environment:
   sdk: ">=2.14.0 <3.0.0"