Added introspection fields for each field on __Type

graphql_schema/lib/src/gen.dart

@@ -1,8 +1,12 @@
 part of graphql_schema.src.schema;
 
 GraphQLObjectType objectType(String name,
-        {String description, Iterable<GraphQLField> fields = const []}) =>
-    new GraphQLObjectType(name, description)..fields.addAll(fields ?? []);
+        {String description,
+        Iterable<GraphQLField> fields = const [],
+        Iterable<GraphQLObjectType> interfaces = const []}) =>
+    new GraphQLObjectType(name, description)
+      ..fields.addAll(fields ?? [])
+      ..interfaces.addAll(interfaces ?? []);
 
 GraphQLField<T, Serialized> field<T, Serialized>(String name,
     {Iterable<GraphQLFieldArgument<T, Serialized>> arguments: const [],

graphql_schema/lib/src/object_type.dart

@@ -7,6 +7,9 @@ class GraphQLObjectType
   final String description;
   final List<GraphQLField> fields = [];
 
+  /// A list of other types that this object type is known to implement.
+  final List<GraphQLObjectType> interfaces = [];
+
   GraphQLObjectType(this.name, this.description);
 
   @override

graphql_server/lib/introspection.dart

@@ -38,6 +38,7 @@ GraphQLSchema reflectSchema(GraphQLSchema schema, List<GraphQLType> allTypes) {
     _reflectFields(),
     _reflectDirectiveType(),
     _reflectInputValueType(),
+    _reflectEnumValueType(),
   ]);
 
   var fields = <GraphQLField>[
@@ -87,6 +88,31 @@ GraphQLObjectType _reflectSchemaTypes() {
       ),
     );
 
+    _typeType.fields.add(
+      field(
+        'interfaces',
+        type: listType(_reflectSchemaTypes().nonNullable()),
+        resolve: (type, _) {
+          if (type is GraphQLObjectType) {
+            return type.interfaces;
+          } else {
+            return <GraphQLType>[];
+          }
+        },
+      ),
+    );
+
+    _typeType.fields.add(
+      field(
+        'possibleTypes',
+        type: listType(_reflectSchemaTypes().nonNullable()),
+        resolve: (type, _) {
+          // TODO: Interface and union types
+          return <GraphQLType>[];
+        },
+      ),
+    );
+
     var fieldType = _reflectFields();
     var inputValueType = _reflectInputValueType();
     var typeField = fieldType.fields
@@ -120,7 +146,9 @@ GraphQLObjectType _reflectSchemaTypes() {
 }
 
 GraphQLObjectType _createTypeType() {
+  var enumValueType = _reflectEnumValueType();
   var fieldType = _reflectFields();
+  var inputValueType = _reflectInputValueType();
 
   return objectType('__Type', fields: [
     field(
@@ -169,6 +197,25 @@ GraphQLObjectType _createTypeType() {
               .toList()
           : [],
     ),
+    field(
+      'enumValues',
+      type: listType(enumValueType.nonNullable()),
+      arguments: [
+        new GraphQLFieldArgument(
+          'includeDeprecated',
+          graphQLBoolean,
+          defaultValue: false,
+        ),
+      ],
+    ),
+    field(
+      'inputFields',
+      type: listType(inputValueType.nonNullable()),
+      resolve: (obj, _) {
+        // TODO: INPUT_OBJECT type
+        return <GraphQLFieldArgument>[];
+      },
+    ),
   ]);
 }
 
@@ -261,6 +308,12 @@ GraphQLObjectType _reflectDirectiveType() {
   ]);
 }
 
+GraphQLObjectType _enumValueType;
+
+GraphQLObjectType _reflectEnumValueType() {
+  return _enumValueType ?? objectType('__EnumValue', fields: []);
+}
+
 List<GraphQLObjectType> fetchAllTypes(GraphQLSchema schema) {
   var typess = <GraphQLType>[];
   typess.addAll(_fetchAllTypesFromObject(schema.query));