Add disallowUnrecognizedKeys option (#212)

Author: jakemac53

json_annotation/CHANGELOG.md

@@ -1,3 +1,10 @@
+## 0.2.7
+
+* Added `JsonSerializable.disallowUnrecognizedKeys`.
+  * Added a helper function to support this option. This function starts with a
+    `$` and should only be referenced by generated code. It is not meant for
+    direct use.
+
 ## 0.2.6
 
 * `CheckedFromJsonException`
@@ -29,7 +36,7 @@
 
 ## 0.2.2
 
-* Added a helper class – `$JsonMapWrapper` – and helper functions – `$wrapMap`, 
+* Added a helper class – `$JsonMapWrapper` – and helper functions – `$wrapMap`,
   `$wrapMapHandleNull`, `$wrapList`, and `$wrapListHandleNull` – to support
   the `useWrappers` option added to `JsonSerializableGenerator` in `v0.3.0` of
   `package:json_serializable`.

json_annotation/lib/json_annotation.dart

@@ -10,6 +10,7 @@
 /// enabled.
 library json_annotation;
 
+export 'src/allowed_keys_helpers.dart';
 export 'src/checked_helpers.dart';
 export 'src/json_literal.dart';
 export 'src/json_serializable.dart';

json_annotation/lib/src/allowed_keys_helpers.dart

@@ -0,0 +1,36 @@
+// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// Helper function used in generated code when
+/// `JsonSerializable.disallowUnrecognizedKeys` is `true`.
+///
+/// Should not be used directly.
+void $checkAllowedKeys(Map map, Iterable<String> allowedKeys) {
+  if (map == null) return;
+  var invalidKeys = map.keys.where((k) => !allowedKeys.contains(k));
+  if (invalidKeys.isNotEmpty) {
+    throw new UnrecognizedKeysException(
+        new List<String>.from(invalidKeys), map, allowedKeys.toList());
+  }
+}
+
+/// Exception thrown if there is an unrecognized key in a json map that was
+/// provided during deserialization.
+class UnrecognizedKeysException implements Exception {
+  /// The allowed keys for [map].
+  final List<String> allowedKeys;
+
+  /// The keys from [map] that were unrecognized.
+  final List<String> unrecognizedKeys;
+
+  /// The source [Map] that the key was found in.
+  final Map map;
+
+  /// A human-readable message corresponding to the error.
+  String get message =>
+      'Unrecognized keys [${unrecognizedKeys.join(', ')}], supported keys  are '
+      '[${allowedKeys.join(', ')}]';
+
+  UnrecognizedKeysException(this.unrecognizedKeys, this.map, this.allowedKeys);
+}

json_annotation/lib/src/checked_helpers.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'allowed_keys_helpers.dart';
+
 /// Helper function used in generated code when
 /// `JsonSerializableGenerator.checked` is `true`.
 ///
@@ -85,6 +87,12 @@ class CheckedFromJsonException implements Exception {
       : _className = className,
         message = _getMessage(innerError);
 
-  static String _getMessage(Object error) =>
-      (error is ArgumentError) ? error.message?.toString() : null;
+  static String _getMessage(Object error) {
+    if (error is ArgumentError) {
+      return error.message?.toString();
+    } else if (error is UnrecognizedKeysException) {
+      return error.message;
+    }
+    return null;
+  }
 }

json_annotation/lib/src/json_serializable.dart

@@ -4,6 +4,12 @@
 
 /// An annotation used to specify a class to generate code for.
 class JsonSerializable {
+  /// If `false` (the default), then any unrecognized keys passed to the
+  /// generated FromJson factory will be ignored.
+  ///
+  /// If `true`, any unrecognized keys will be treated as an error.
+  final bool disallowUnrecognizedKeys;
+
   /// If `true` (the default), a private, static `_$ExampleFromJson` method
   /// is created in the generated part file.
   ///
@@ -48,11 +54,13 @@ class JsonSerializable {
 
   /// Creates a new [JsonSerializable] instance.
   const JsonSerializable(
-      {bool createFactory: true,
+      {bool disallowUnrecognizedKeys: false,
+      bool createFactory: true,
       bool createToJson: true,
       bool includeIfNull: true,
       bool nullable: true})
-      : this.createFactory = createFactory ?? true,
+      : this.disallowUnrecognizedKeys = disallowUnrecognizedKeys ?? false,
+        this.createFactory = createFactory ?? true,
         this.createToJson = createToJson ?? true,
         this.includeIfNull = includeIfNull ?? true,
         this.nullable = nullable ?? true;

json_annotation/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_annotation
-version: 0.2.6
+version: 0.2.7-dev
 description: >-
   Classes and helper functions that support JSON code generation via the
   `json_serializable` package.

json_serializable/CHANGELOG.md

@@ -1,3 +1,12 @@
+## 0.5.6
+
+* Added support for `JsonSerializable.disallowUnrecognizedKeys`.
+  * Throws an `UnrecognizedKeysException` if it finds unrecognized keys in the
+    JSON map used to create the annotated object.
+  * Will be captured captured and wrapped in a `CheckedFromJsonException` if
+    `checked` is enabled in `json_serializable`.
+* All `fromJson` constructors now use block syntax instead of fat arrows.
+
 ## 0.5.5
 
 * Added support for `JsonKey.defaultValue`.
@@ -35,9 +44,9 @@
 
 * If `JsonKey.fromJson` function parameter is `Iterable` or `Map` with type
    arguments of `dynamic` or `Object`, omit the arguments when generating a
-   cast. 
+   cast.
    `_myHelper(json['key'] as Map)` instead of
-   `_myHelper(json['key'] as Map<dynamic, dynamic>)`.  
+   `_myHelper(json['key'] as Map<dynamic, dynamic>)`.
 
 * `JsonKey.fromJson`/`.toJson` now support functions with optional arguments.
 

json_serializable/README.md

@@ -41,10 +41,12 @@ Building creates the corresponding part `example.g.dart`:
 ```dart
 part of 'example.dart';
 
-Person _$PersonFromJson(Map<String, dynamic> json) => new Person(
-    firstName: json['firstName'] as String,
-    lastName: json['lastName'] as String,
-    dateOfBirth: DateTime.parse(json['dateOfBirth'] as String));
+Person _$PersonFromJson(Map<String, dynamic> json) {
+  return new Person(
+      firstName: json['firstName'] as String,
+      lastName: json['lastName'] as String,
+      dateOfBirth: DateTime.parse(json['dateOfBirth'] as String));
+}
 
 abstract class _$PersonSerializerMixin {
   String get firstName;

json_serializable/example/example.g.dart

@@ -10,10 +10,12 @@ part of 'example.dart';
 // Generator: JsonSerializableGenerator
 // **************************************************************************
 
-Person _$PersonFromJson(Map<String, dynamic> json) => new Person(
-    firstName: json['firstName'] as String,
-    lastName: json['lastName'] as String,
-    dateOfBirth: DateTime.parse(json['dateOfBirth'] as String));
+Person _$PersonFromJson(Map<String, dynamic> json) {
+  return new Person(
+      firstName: json['firstName'] as String,
+      lastName: json['lastName'] as String,
+      dateOfBirth: DateTime.parse(json['dateOfBirth'] as String));
+}
 
 abstract class _$PersonSerializerMixin {
   String get firstName;

json_serializable/lib/src/generator_helper.dart

@@ -141,7 +141,7 @@ class _GeneratorHelper {
       var mapType = _generator.anyMap ? 'Map' : 'Map<String, dynamic>';
       _buffer.write('$_targetClassReference '
           '${_prefix}FromJson${_genericClassArguments(true)}'
-          '($mapType json) =>');
+          '($mapType json) {\n');
 
       String deserializeFun(String paramOrFieldName,
               {ParameterElement ctorParam}) =>
@@ -152,10 +152,11 @@ class _GeneratorHelper {
       if (_generator.checked) {
         var classLiteral = escapeDartString(_element.name);
 
-        _buffer.write(''' \$checkedNew(
+        _buffer.write('''
+  return \$checkedNew(
     $classLiteral,
     json,
-    ()''');
+    () {''');
 
         var data = writeConstructorInvocation(
             _element,
@@ -169,31 +170,28 @@ class _GeneratorHelper {
 
         fieldsSetByFactory = data.usedCtorParamsAndFields;
 
-        if (data.fieldsToSet.isEmpty) {
-          // Use simple arrow syntax for the constructor invocation.
-          // There are no fields to set
-          _buffer.write(' => ${data.content}');
-        } else {
-          // If there are fields to set, create a full function body and
-          // create a temporary variable to hold the instance so we can make
-          // wrapped calls to all of the fields value assignments.
-          _buffer.write(''' {
-      var val = ''');
-          _buffer.write(data.content);
-          _buffer.writeln(';');
-
-          for (var field in data.fieldsToSet) {
-            _buffer.writeln();
-            var safeName = _safeNameAccess(accessibleFields[field]);
-            _buffer.write('''
+        if (_annotation.disallowUnrecognizedKeys) {
+          var listLiteral = jsonLiteralAsDart(
+              accessibleFields.values.map(_nameAccess).toList(), true);
+          _buffer.write('''
+      \$checkAllowedKeys(json, $listLiteral);''');
+        }
+        _buffer.write('''
+      var val = ${data.content};''');
+
+        for (var field in data.fieldsToSet) {
+          _buffer.writeln();
+          var safeName = _safeNameAccess(accessibleFields[field]);
+          _buffer.write('''
       \$checkedConvert(json, $safeName, (v) => ''');
-            _buffer.write('val.$field = ');
-            _buffer.write(_deserializeForField(accessibleFields[field],
-                checkedProperty: true));
-            _buffer.write(');');
-          }
-          _buffer.writeln('return val; }');
+          _buffer.write('val.$field = ');
+          _buffer.write(_deserializeForField(accessibleFields[field],
+              checkedProperty: true));
+          _buffer.write(');');
         }
+
+        _buffer.writeln('return val; }');
+
         var fieldKeyMap = new Map.fromEntries(fieldsSetByFactory
             .map((k) => new MapEntry(k, _nameAccess(accessibleFields[k])))
             .where((me) => me.key != me.value));
@@ -206,7 +204,9 @@ class _GeneratorHelper {
           fieldKeyMapArg = ', fieldKeyMap: $mapLiteral';
         }
 
-        _buffer.write('$fieldKeyMapArg)');
+        _buffer.write(fieldKeyMapArg);
+
+        _buffer.write(')');
       } else {
         var data = writeConstructorInvocation(
             _element,
@@ -220,14 +220,25 @@ class _GeneratorHelper {
 
         fieldsSetByFactory = data.usedCtorParamsAndFields;
 
-        _buffer.write(' ${data.content}');
+        if (_annotation.disallowUnrecognizedKeys) {
+          var listLiteral = jsonLiteralAsDart(
+              fieldsSetByFactory
+                  .map((k) => _nameAccess(accessibleFields[k]))
+                  .toList(),
+              true);
+          _buffer.write('''
+  \$checkAllowedKeys(json, $listLiteral);''');
+        }
+
+        _buffer.write('''
+  return ${data.content}''');
         for (var field in data.fieldsToSet) {
           _buffer.writeln();
-          _buffer.write('  ..$field = ');
+          _buffer.write('    ..$field = ');
           _buffer.write(deserializeFun(field));
         }
       }
-      _buffer.writeln(';');
+      _buffer.writeln(';\n}');
       _buffer.writeln();
 
       // If there are fields that are final – that are not set via the generated

json_serializable/lib/src/utils.dart

@@ -14,6 +14,8 @@ import 'package:source_gen/source_gen.dart';
 
 JsonSerializable valueForAnnotation(ConstantReader annotation) =>
     new JsonSerializable(
+        disallowUnrecognizedKeys:
+            annotation.read('disallowUnrecognizedKeys').boolValue,
         createToJson: annotation.read('createToJson').boolValue,
         createFactory: annotation.read('createFactory').boolValue,
         nullable: annotation.read('nullable').boolValue,

json_serializable/pubspec.yaml

@@ -1,5 +1,5 @@
 name: json_serializable
-version: 0.5.5
+version: 0.5.6-dev
 author: Dart Team <misc@dartlang.org>
 description: Generates utilities to aid in serializing to/from JSON.
 homepage: https://github.com/dart-lang/json_serializable
@@ -12,7 +12,7 @@ dependencies:
 
   # Use a tight version constraint to ensure that a constraint on
   # `json_annotation`. Properly constrains all features it provides.
-  json_annotation: '>=0.2.6 <0.2.7'
+  json_annotation: '>=0.2.7 <0.2.8'
   meta: ^1.1.0
   path: ^1.3.2
   source_gen: '>=0.8.1 <0.9.0'
@@ -25,3 +25,7 @@ dev_dependencies:
   logging: ^0.11.3+1
   test: ^0.12.3
   yaml: ^2.1.13
+
+dependency_overrides:
+  json_annotation:
+    path: ../json_annotation