[flutter_markdown] fix invalid URI's causing unhandled image errors (#8058)
This PR adds an error builder for images, so that any errors from those are caught.
*List which issues are fixed by this PR. You must list at least one issue.*
Fixes https://github.com/flutter/flutter/issues/158428
diff --git a/packages/flutter_markdown/CHANGELOG.md b/packages/flutter_markdown/CHANGELOG.md
index 40c40d6..0c43f4f 100644
--- a/packages/flutter_markdown/CHANGELOG.md
+++ b/packages/flutter_markdown/CHANGELOG.md
@@ -1,6 +1,10 @@
+## 0.7.4+3
+
+* Passes a default error builder to image widgets.
+
## 0.7.4+2
-* Fixes pub.dev detection of WebAssembly support.
+* Fixes pub.dev detection of WebAssembly support.
## 0.7.4+1
diff --git a/packages/flutter_markdown/lib/src/_functions_io.dart b/packages/flutter_markdown/lib/src/_functions_io.dart
index b302057..965d617 100644
--- a/packages/flutter_markdown/lib/src/_functions_io.dart
+++ b/packages/flutter_markdown/lib/src/_functions_io.dart
@@ -24,23 +24,62 @@
double? height,
) {
if (uri.scheme == 'http' || uri.scheme == 'https') {
- return Image.network(uri.toString(), width: width, height: height);
+ return Image.network(
+ uri.toString(),
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
} else if (uri.scheme == 'data') {
return _handleDataSchemeUri(uri, width, height);
} else if (uri.scheme == 'resource') {
- return Image.asset(uri.path, width: width, height: height);
+ return Image.asset(
+ uri.path,
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
} else {
final Uri fileUri = imageDirectory != null
? Uri.parse(imageDirectory + uri.toString())
: uri;
if (fileUri.scheme == 'http' || fileUri.scheme == 'https') {
- return Image.network(fileUri.toString(), width: width, height: height);
+ return Image.network(
+ fileUri.toString(),
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
} else {
- return Image.file(File.fromUri(fileUri), width: width, height: height);
+ try {
+ return Image.file(
+ File.fromUri(fileUri),
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
+ } catch (error, stackTrace) {
+ // Handle any invalid file URI's.
+ return Builder(
+ builder: (BuildContext context) {
+ return kDefaultImageErrorWidgetBuilder(context, error, stackTrace);
+ },
+ );
+ }
}
}
};
+/// A default error widget builder for handling image errors.
+// ignore: prefer_function_declarations_over_variables
+final ImageErrorWidgetBuilder kDefaultImageErrorWidgetBuilder = (
+ BuildContext context,
+ Object error,
+ StackTrace? stackTrace,
+) {
+ return const SizedBox();
+};
+
/// A default style sheet generator.
final MarkdownStyleSheet Function(BuildContext, MarkdownStyleSheetBaseTheme?)
// ignore: prefer_function_declarations_over_variables
@@ -76,6 +115,7 @@
uri.data!.contentAsBytes(),
width: width,
height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
);
} else if (mimeType.startsWith('text/')) {
return Text(uri.data!.contentAsString());
diff --git a/packages/flutter_markdown/lib/src/_functions_web.dart b/packages/flutter_markdown/lib/src/_functions_web.dart
index abf2345..d1aade0 100644
--- a/packages/flutter_markdown/lib/src/_functions_web.dart
+++ b/packages/flutter_markdown/lib/src/_functions_web.dart
@@ -25,24 +25,68 @@
double? height,
) {
if (uri.scheme == 'http' || uri.scheme == 'https') {
- return Image.network(uri.toString(), width: width, height: height);
+ return Image.network(
+ uri.toString(),
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
} else if (uri.scheme == 'data') {
return _handleDataSchemeUri(uri, width, height);
} else if (uri.scheme == 'resource') {
- return Image.asset(uri.path, width: width, height: height);
+ return Image.asset(
+ uri.path,
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
} else {
- final Uri fileUri = imageDirectory != null
- ? Uri.parse(p.join(imageDirectory, uri.toString()))
- : uri;
+ final Uri fileUri;
+
+ if (imageDirectory != null) {
+ try {
+ fileUri = Uri.parse(p.join(imageDirectory, uri.toString()));
+ } catch (error, stackTrace) {
+ // Handle any invalid file URI's.
+ return Builder(
+ builder: (BuildContext context) {
+ return kDefaultImageErrorWidgetBuilder(context, error, stackTrace);
+ },
+ );
+ }
+ } else {
+ fileUri = uri;
+ }
+
if (fileUri.scheme == 'http' || fileUri.scheme == 'https') {
- return Image.network(fileUri.toString(), width: width, height: height);
+ return Image.network(
+ fileUri.toString(),
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
} else {
final String src = p.join(p.current, fileUri.toString());
- return Image.network(src, width: width, height: height);
+ return Image.network(
+ src,
+ width: width,
+ height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
+ );
}
}
};
+/// A default error widget builder for handling image errors.
+// ignore: prefer_function_declarations_over_variables
+final ImageErrorWidgetBuilder kDefaultImageErrorWidgetBuilder = (
+ BuildContext context,
+ Object error,
+ StackTrace? stackTrace,
+) {
+ return const SizedBox();
+};
+
/// A default style sheet generator.
final MarkdownStyleSheet Function(BuildContext, MarkdownStyleSheetBaseTheme?)
// ignore: prefer_function_declarations_over_variables
@@ -72,6 +116,7 @@
uri.data!.contentAsBytes(),
width: width,
height: height,
+ errorBuilder: kDefaultImageErrorWidgetBuilder,
);
} else if (mimeType.startsWith('text/')) {
return Text(uri.data!.contentAsString());
diff --git a/packages/flutter_markdown/lib/src/builder.dart b/packages/flutter_markdown/lib/src/builder.dart
index ea9af16..50bdd11 100644
--- a/packages/flutter_markdown/lib/src/builder.dart
+++ b/packages/flutter_markdown/lib/src/builder.dart
@@ -601,7 +601,12 @@
}
}
- final Uri uri = Uri.parse(path);
+ final Uri? uri = Uri.tryParse(path);
+
+ if (uri == null) {
+ return const SizedBox();
+ }
+
Widget child;
if (imageBuilder != null) {
child = imageBuilder!(uri, title, alt);
diff --git a/packages/flutter_markdown/pubspec.yaml b/packages/flutter_markdown/pubspec.yaml
index b15a738..b78c0dc 100644
--- a/packages/flutter_markdown/pubspec.yaml
+++ b/packages/flutter_markdown/pubspec.yaml
@@ -4,7 +4,7 @@
formatted with simple Markdown tags.
repository: https://github.com/flutter/packages/tree/main/packages/flutter_markdown
issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+flutter_markdown%22
-version: 0.7.4+2
+version: 0.7.4+3
environment:
sdk: ^3.3.0
diff --git a/packages/flutter_markdown/test/image_test.dart b/packages/flutter_markdown/test/image_test.dart
index 00677f1..07a4e87 100644
--- a/packages/flutter_markdown/test/image_test.dart
+++ b/packages/flutter_markdown/test/image_test.dart
@@ -334,6 +334,46 @@
);
testWidgets(
+ 'should gracefully handle image URLs with empty scheme',
+ (WidgetTester tester) async {
+ const String data = '';
+ await tester.pumpWidget(
+ boilerplate(
+ const Markdown(data: data),
+ ),
+ );
+
+ expect(find.byType(Image), findsNothing);
+ expect(tester.takeException(), isNull);
+ },
+ );
+
+ testWidgets(
+ 'should gracefully handle image URLs with invalid scheme',
+ (WidgetTester tester) async {
+ const String data = '';
+ await tester.pumpWidget(
+ boilerplate(
+ const Markdown(data: data),
+ ),
+ );
+
+ // On the web, any URI with an unrecognized scheme is treated as a network image.
+ // Thus the error builder of the Image widget is called.
+ // On non-web, any URI with an unrecognized scheme is treated as a file image.
+ // However, constructing a file from an invalid URI will throw an exception.
+ // Thus the Image widget is never created, nor is its error builder called.
+ if (kIsWeb) {
+ expect(find.byType(Image), findsOneWidget);
+ } else {
+ expect(find.byType(Image), findsNothing);
+ }
+
+ expect(tester.takeException(), isNull);
+ },
+ );
+
+ testWidgets(
'should gracefully handle width parsing failures',
(WidgetTester tester) async {
const String data = '';
