typed events

functions_framework/lib/src/cloud_event.dart

@@ -13,11 +13,19 @@
 // limitations under the License.
 
 import 'package:json_annotation/json_annotation.dart';
+import 'package:meta/meta.dart';
 
 part 'cloud_event.g.dart';
 
-@JsonSerializable(includeIfNull: false, checked: true)
-class CloudEvent {
+@internal
+typedef FromJson<T> = T Function(Map<String, dynamic> json);
+
+@JsonSerializable(
+  includeIfNull: false,
+  checked: true,
+  genericArgumentFactories: true,
+)
+class CloudEvent<T> {
   @JsonKey(required: true)
   final String id;
   @JsonKey(required: true)
@@ -30,7 +38,7 @@ class CloudEvent {
 
   @JsonKey(name: 'datacontenttype')
   final String? dataContentType;
-  final Object? data;
+  final T data;
 
   @JsonKey(name: 'dataschema')
   final Uri? dataSchema;
@@ -42,15 +50,21 @@ class CloudEvent {
     required this.source,
     required this.specVersion,
     required this.type,
-    this.data,
+    required this.data,
     this.dataContentType,
     this.dataSchema,
     this.subject,
     this.time,
   });
 
-  factory CloudEvent.fromJson(Map<String, dynamic> json) =>
-      _$CloudEventFromJson(json);
+  factory CloudEvent.fromJson(
+    Map<String, dynamic> json,
+    FromJson<T> fromJsonT,
+  ) =>
+      _$CloudEventFromJson(
+        json,
+        (value) => fromJsonT(value as Map<String, dynamic>),
+      );
 
-  Map<String, dynamic> toJson() => _$CloudEventToJson(this);
+  Map<String, dynamic> toJson() => _$CloudEventToJson(this, (val) => val);
 }

functions_framework/lib/src/function_target.dart

@@ -34,13 +34,15 @@ abstract class FunctionTarget {
     HandlerWithLogger function,
   ) = HttpWithLoggerFunctionTarget;
 
-  factory FunctionTarget.cloudEvent(
-    CloudEventHandler function,
-  ) = CloudEventFunctionTarget;
-
-  factory FunctionTarget.cloudEventWithContext(
-    CloudEventWithContextHandler function,
-  ) = CloudEventWithContextFunctionTarget;
+  static FunctionTarget cloudEvent<T>(
+    CloudEventHandler<T> function,
+  ) =>
+      CloudEventFunctionTarget<T>(function);
+
+  static FunctionTarget cloudEventWithContext<T>(
+    CloudEventWithContextHandler<T> function,
+  ) =>
+      CloudEventWithContextFunctionTarget<T>(function);
 
   FutureOr<Response> handler(Request request);
 }

functions_framework/lib/src/targets/cloud_event_targets.dart

@@ -24,49 +24,55 @@ import '../json_request_utils.dart';
 import '../request_context.dart';
 import '../typedefs.dart';
 
-class CloudEventFunctionTarget extends FunctionTarget {
-  final CloudEventHandler function;
+abstract class _CloudEventFunctionTarget<T> extends FunctionTarget {
+  _CloudEventFunctionTarget();
+
+  Future<CloudEvent<T>> _eventFromRequest(Request request) async =>
+      _requiredBinaryHeader.every(request.headers.containsKey)
+          ? await _decodeBinary(request, _decode)
+          : await _decodeStructured(request, _decode);
+
+  T _decode(Map<String, dynamic> json) => json as T;
+}
+
+class CloudEventFunctionTarget<T> extends _CloudEventFunctionTarget<T> {
+  final CloudEventHandler<T> function;
 
   @override
   FunctionType get type => FunctionType.cloudevent;
 
   @override
   FutureOr<Response> handler(Request request) async {
     final event = await _eventFromRequest(request);
-
     await function(event);
-
     return Response.ok('');
   }
 
   CloudEventFunctionTarget(this.function);
 }
 
-class CloudEventWithContextFunctionTarget extends FunctionTarget {
-  final CloudEventWithContextHandler function;
+class CloudEventWithContextFunctionTarget<T>
+    extends _CloudEventFunctionTarget<T> {
+  final CloudEventWithContextHandler<T> function;
 
   @override
   FunctionType get type => FunctionType.cloudevent;
 
   @override
   Future<Response> handler(Request request) async {
     final event = await _eventFromRequest(request);
-
     final context = contextForRequest(request);
     await function(event, context);
-
     return Response.ok('', headers: context.responseHeaders);
   }
 
   CloudEventWithContextFunctionTarget(this.function);
 }
 
-Future<CloudEvent> _eventFromRequest(Request request) =>
-    _requiredBinaryHeader.every(request.headers.containsKey)
-        ? _decodeBinary(request)
-        : _decodeStructured(request);
-
-Future<CloudEvent> _decodeStructured(Request request) async {
+Future<CloudEvent<T>> _decodeStructured<T>(
+  Request request,
+  FromJson<T> fromJson,
+) async {
   final type = mediaTypeFromRequest(request);
 
   mustBeJson(type);
@@ -79,13 +85,20 @@ Future<CloudEvent> _decodeStructured(Request request) async {
     };
   }
 
-  return _decodeValidCloudEvent(jsonObject, 'structured-mode message');
+  return _decodeValidCloudEvent(
+    jsonObject,
+    'structured-mode message',
+    fromJson,
+  );
 }
 
 const _cloudEventPrefix = 'ce-';
 const _clientEventPrefixLength = _cloudEventPrefix.length;
 
-Future<CloudEvent> _decodeBinary(Request request) async {
+Future<CloudEvent<T>> _decodeBinary<T>(
+  Request request,
+  FromJson<T> fromJson,
+) async {
   final type = mediaTypeFromRequest(request);
   mustBeJson(type);
 
@@ -97,15 +110,16 @@ Future<CloudEvent> _decodeBinary(Request request) async {
     'data': await decodeJson(request),
   };
 
-  return _decodeValidCloudEvent(map, 'binary-mode message');
+  return _decodeValidCloudEvent(map, 'binary-mode message', fromJson);
 }
 
-CloudEvent _decodeValidCloudEvent(
+CloudEvent<T> _decodeValidCloudEvent<T>(
   Map<String, dynamic> map,
   String messageType,
+  FromJson<T> fromJson,
 ) {
   try {
-    return CloudEvent.fromJson(map);
+    return CloudEvent.fromJson(map, fromJson);
   } catch (e, stackTrace) {
     throw BadRequestException(
       400,

functions_framework/lib/src/typedefs.dart

@@ -20,10 +20,10 @@ import 'cloud_event.dart';
 import 'log_severity.dart';
 import 'request_context.dart';
 
-typedef CloudEventHandler = FutureOr<void> Function(CloudEvent request);
+typedef CloudEventHandler<T> = FutureOr<void> Function(CloudEvent<T> request);
 
-typedef CloudEventWithContextHandler = FutureOr<void> Function(
-  CloudEvent request,
+typedef CloudEventWithContextHandler<T> = FutureOr<void> Function(
+  CloudEvent<T> request,
   RequestContext context,
 );
 

functions_framework/pubspec.yaml

@@ -21,7 +21,7 @@ dependencies:
 dev_dependencies:
   build_runner: ^1.10.7
   build_verify: ^2.0.0
-  json_serializable: ^4.0.0
+  json_serializable: ^4.0.1
   # Because we use the ignore_for_file build.yaml config
   source_gen: ^1.0.0
   test: ^1.15.7

functions_framework_builder/lib/src/supported_function_type.dart

@@ -50,7 +50,9 @@ class SupportedFunctionType {
         lib.exportNamespace.get(typeDefName) as TypeAliasElement;
 
     final functionType = handlerTypeAlias.instantiate(
-      typeArguments: [],
+      typeArguments: handlerTypeAlias.typeParameters
+          .map((e) => e.instantiate(nullabilitySuffix: NullabilitySuffix.none))
+          .toList(),
       nullabilitySuffix: NullabilitySuffix.none,
     );
 

functions_framework_builder/lib/src/valid_json_utils.dart

@@ -27,19 +27,8 @@ bool _validJsonType(DartType type, bool allowComplexMembers) {
     return memberType.isDynamic || memberType.isDartCoreObject;
   }
 
-  if (type.isDartCoreBool ||
-      type.isDartCoreNum ||
-      type.isDartCoreDouble ||
-      type.isDartCoreInt ||
-      type.isDartCoreString) {
-    return true;
-  }
-
   if (type is InterfaceType) {
-    if (type.isDartCoreList) {
-      final arg = type.typeArguments.single;
-      return validCollectionMember(arg);
-    } else if (type.isDartCoreMap) {
+    if (type.isDartCoreMap) {
       final keyArg = type.typeArguments[0];
       final valueArg = type.typeArguments[1];
       return keyArg.isDartCoreString && validCollectionMember(valueArg);