[go_router] add initial json support #110781

packages/go_router/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 15.1.4
+
+- Adds annotation for go_router_builder that enable custom string encoder/decoder [#110781](https://github.com/flutter/flutter/issues/110781)
+
 ## 15.1.3
 
 * Updates minimum supported SDK version to Flutter 3.27/Dart 3.6.

packages/go_router/lib/go_router.dart

@@ -11,6 +11,7 @@ export 'src/configuration.dart';
 export 'src/delegate.dart';
 export 'src/information_provider.dart';
 export 'src/match.dart' hide RouteMatchListCodec;
+export 'src/misc/custom_parameter.dart';
 export 'src/misc/errors.dart';
 export 'src/misc/extensions.dart';
 export 'src/misc/inherited_router.dart';

packages/go_router/lib/src/misc/custom_parameter.dart

@@ -0,0 +1,40 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:meta/meta_meta.dart';
+
+/// annotation to define a custom parameter decoder/encoder
+/// this is useful when the is encoded/decoded in a non-standard way like base64
+/// this must be used as an annotation on a field
+/// ```dart
+/// String fromBase64(String value) {
+///   return const Utf8Decoder().convert(base64.decode(value));
+/// }
+/// String toBase64(String value) {
+///   return base64.encode(const Utf8Encoder().convert(value));
+/// }
+/// class MyRoute {
+///   @CustomParameterCodec(
+///     encode: toBase64,
+///     decode: fromBase64,
+///   )
+///   final String data;
+///   MyRoute(this.data);
+/// }
+/// ```
+@Target({TargetKind.field})
+class CustomParameterCodec {
+  /// create a custom parameter codec
+  ///
+  const CustomParameterCodec({
+    required this.encode,
+    required this.decode,
+  });
+
+  /// custom function to encode the field
+  final String Function(String json) encode;
+
+  /// custom function to decode the field
+  final String Function(String json) decode;
+}

packages/go_router/pubspec.yaml

@@ -1,7 +1,7 @@
 name: go_router
 description: A declarative router for Flutter based on Navigation 2 supporting
   deep linking, data-driven routes and more
-version: 15.1.3
+version: 15.1.4
 repository: https://github.com/flutter/packages/tree/main/packages/go_router
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+go_router%22