Use Flutter compute for parsing models (#408)

* Format code

* Fix pubspec

* Generate compute calls

* Add tests

* Update parser name

* Format code

* Fix merge conflict

* Add examples for post methods

* Define a new parser annotation for using the Flutter  function

* Increment to version 3.0.0 with documentation for implementing the FlutterCompute parser option

* Upgrade to version 3.0.0

* Use serialize and deserialize functions

* Update documentation to match implementation better

* Fix generating compute for requests body

* Handle queries

* Add tests for FlutterCompute parser

* Update documentation

* Ignore computing unserialised objects

* Fix nullable bodies and add warnings for spawning for collections

* Serialise lists

* Handle lists for objects in one function

* Fix casting lists

* Fix tests

* Remove failed check

* Revert "Remove failed check"

This reverts commit 91b8037.

* Fix tests

* Update CHANGELOG

Co-authored-by: Trevor Wang <[email protected]>

README.md

@@ -223,7 +223,14 @@ If you want to parse models on a separate thread, you can take advantage of the
 For each model that you use you will need to define 2 top-level functions:
 ```dart
 FutureOr<Task> deserializeTask(Map<String, dynamic> json);
-FutureOr<Map<String, dynamic>> serializeTask(Task object);
+FutureOr<dynamic> serializeTask(Task object);
+```
+
+If you want to handle lists of objects, either as return types or parameters, you should provide List counterparts.
+
+```dart
+FutureOr<List<Task>> deserializeTaskList(Map<String, dynamic> json);
+FutureOr<dynamic> serializeTaskList(List<Task> objects);
 ```
 
 E.g.
@@ -235,40 +242,54 @@ E.g.
 abstract class RestClient {
   factory RestClient(Dio dio, {String baseUrl}) = _RestClient;
 
+  @GET("/task")
+  Future<Task> getTask();
   @GET("/tasks")
   Future<List<Task>> getTasks();
 
+  @POST("/task")
+  Future<void> updateTasks(Task task);
   @POST("/tasks")
   Future<void> updateTasks(List<Task> tasks);
 }
 
 Task deserializeTask(Map<String, dynamic> json) => Task.fromJson(json);
-Map<String, dynamic> serializeTask(User object) => object.toJson();
+List<Task> deserializeTaskList(List<Map<String, dynamic>> json) =>
+    json.map((e) => Task.fromJson(e)).toList();
+Map<String, dynamic> serializeTask(Task object) => object.toJson();
+List<Map<String, dynamic>> serializeTaskList(List<Task> objects) =>
+    objects.map((e) => e.toJson()).toList();
 ```
 
 N.B.
-It is recommended to use just a single object, if possible, as then only one background thread will be spawned to perform the computation. If you use a list or a map it will spawn a thread for each element.
+Avoid using Map values, otherwise multiple background isolates will be spawned to perform the computation, which is extremely intensive for Dart.
 
 ```dart
 abstract class RestClient {
   factory RestClient(Dio dio, {String baseUrl}) = _RestClient;
 
+  // BAD
   @GET("/tasks")
-  Future<List<Task>> getTasks(); // BAD
+  Future<Map<String, Task>> getTasks();
+  @POST("/tasks")
+  Future<void> updateTasks(Map<String, Task> tasks);
 
-  @GET("/tasks_list")
-  Future<TaskList> getTasksList(); // GOOD
+  // GOOD
+  @GET("/tasks_names")
+  Future<TaskNames> getTaskNames();
+  @POST("/tasks_names")
+  Future<void> updateTasks(TaskNames tasks);
 }
 
-TaskList deserializeTaskList(Map<String, dynamic> json) => TaskList.fromJson(json);
+TaskNames deserializeTaskNames(Map<String, dynamic> json) => TaskNames.fromJson(json);
 
 @JsonSerializable
-class TaskList {
-  const TaskList({required this.tasks});
+class TaskNames {
+  const TaskNames({required this.tasks});
 
-  final List<Task> tasks;
+  final Map<String, Task> taskNames;
 
-  factory TaskList.fromJson(Map<String, dynamic> json) => _$TaskListFromJson(json);
+  factory TaskNames.fromJson(Map<String, dynamic> json) => _$TaskNamesFromJson(json);
 }
 ```
 

annotation/lib/http.dart

@@ -30,15 +30,26 @@ enum Parser {
   /// Each model class must define a top-level function, taking the form
   /// ```
   /// FutureOr<T> deserializeT(Map<String, dynamic> json);
-  /// FutureOr<Map<String, dynamic>> serializeTask(T object);
+  /// FutureOr<dynamic> serializeTask(T object);
+  /// ```
+  ///
+  /// If you want to handle lists of objects, either as return types or parameters, you should provide List counterparts.
+  ///
+  /// ```
+  /// FutureOr<List<T>> deserializeTList(Map<String, dynamic> json);
+  /// FutureOr<dynamic> serializeTList(List<T> objects);
   /// ```
   ///
   /// E.g.
   /// ----
   /// _In file user.dart_
   /// ```
   /// User deserializeUser(Map<String, dynamic> json) => User.fromJson(json);
+  /// List<User> deserializeUserList(List<Map<String, dynamic>> json) =>
+  ///     json.map((e) => User.fromJson(e)).toList();
   /// Map<String, dynamic> serializeUser(User object) => object.toJson();
+  /// List<Map<String, dynamic>> serializeUserList(List<User> objects) =>
+  ///     objects.map((e) => e.toJson()).toList();
   ///
   /// @JsonSerializable()
   /// class User {

example_dartmapper/pubspec.yaml

@@ -16,7 +16,7 @@ dependencies:
 dev_dependencies:
   test: 1.16.5
   retrofit_generator:
-  build_runner: ^1.12.2
+  build_runner: ^2.0.1
   json_serializable: ^4.0.3
   mock_web_server:
 

flutter_example/lib/example.dart

@@ -1,14 +1,80 @@
-import 'mock_adapter.dart';
-import 'package:retrofit/retrofit.dart';
 import 'package:dio/dio.dart' hide Headers;
+import 'package:flutter/foundation.dart';
+import 'package:json_annotation/json_annotation.dart';
+import 'package:retrofit/retrofit.dart';
+
+import 'mock_adapter.dart';
 
 part 'example.g.dart';
 
-@RestApi(baseUrl: "http://baidu.com")
+User deserializeUser(Map<String, dynamic> json) => User.fromJson(json);
+List<User> deserializeUserList(List<Map<String, dynamic>> json) =>
+    json.map((e) => User.fromJson(e)).toList();
+Map<String, dynamic> serializeUser(User object) => object.toJson();
+List<Map<String, dynamic>> serializeUserList(List<User> objects) =>
+    objects.map((e) => e.toJson()).toList();
+
+@JsonSerializable()
+class User {
+  User({required this.id});
+
+  final String id;
+
+  factory User.fromJson(Map<String, dynamic> json) => _$UserFromJson(json);
+  Map<String, dynamic> toJson() => _$UserToJson(this);
+}
+
+@RestApi(baseUrl: "http://baidu.com", parser: Parser.FlutterCompute)
 abstract class RestClient {
   factory RestClient(Dio dio, {String baseUrl}) = _RestClient;
+
   @GET('/tags')
   Future<List<String>> getTags({@DioOptions() Options? options});
+  @GET('/tagsNullable')
+  Future<List<String>?> getTagsNullable({@DioOptions() Options? options});
+  @GET('/tagByKey')
+  Future<Map<String, String>> getTagByKey({@DioOptions() Options? options});
+  @GET('/tagByKeyNullable')
+  Future<Map<String, String>?> getTagByKeyNullable(
+      {@DioOptions() Options? options});
+  @GET('/tag')
+  Future<String> getTag({@DioOptions() Options? options});
+  @GET('/tagNullable')
+  Future<String?> getTagNullable({@DioOptions() Options? options});
+
+  @GET('/users')
+  Future<List<User>> getUsers({@DioOptions() Options? options});
+  @GET('/usersNullable')
+  Future<List<User>?> getUsersNullable({@DioOptions() Options? options});
+  @GET('/userByKey')
+  Future<Map<String, User>> getUserByKey({@DioOptions() Options? options});
+  @GET('/userByKeyNullable')
+  Future<Map<String, User>?> getUserByKeyNullable(
+      {@DioOptions() Options? options});
+  @GET('/usersByKey')
+  Future<Map<String, List<User>>> getUsersByKey(
+      {@DioOptions() Options? options});
+  @GET('/user')
+  Future<User> getUser({@DioOptions() Options? options});
+  @GET('/userNullable')
+  Future<User?> getUserNullable({@DioOptions() Options? options});
+
+  @PATCH('/user/{user}')
+  Future<void> patchUser(
+      {@Query('u') required User user, @DioOptions() Options? options});
+  @PATCH('/userMap/{user}')
+  Future<void> patchUserMap(
+      {@Queries() required User user, @DioOptions() Options? options});
+
+  @POST('/users')
+  Future<void> postUsers(
+      {@Body() required List<User> users, @DioOptions() Options? options});
+  @POST('/user')
+  Future<void> postUser(
+      {@Body() required User user, @DioOptions() Options? options});
+  @POST('/userNullable')
+  Future<void> postUserNullable(
+      {@Body() required User? user, @DioOptions() Options? options});
 }
 
 void test() {
@@ -23,7 +89,7 @@ void test() {
     handler.next(options);
   }));
   final api = RestClient(dio, baseUrl: MockAdapter.mockBase);
-  api.getTags().then((it) {
+  api.getUsers().then((it) {
     print(it.length);
   });
 }