Flutter Firebase云函数集成插件dart_firebase_functions_builder的使用

Flutter Firebase云函数集成插件dart_firebase_functions_builder的使用

动机

本项目旨在为Dart提供类似Node.js firebase-functions包的功能，使用了functions_framework和dart_firebase_admin包。

如何使用

安装

请在你的Flutter应用的pubspec.yaml文件中添加以下依赖：

dependencies:
  dart_firebase_admin: latest
  dart_firebase_functions: latest
  functions_framework: latest
  shelf:

dev_dependencies:
  build_runner:
  dart_firebase_functions_builder: latest

定义adminApp

在定义函数之前，需要配置FirebaseAdminApp并使用你的凭证。

import 'package:dart_firebase_admin/dart_firebase_admin.dart';
import 'package:dart_firebase_functions/dart_firebase_functions.dart';
import 'package:functions_framework/functions_framework.dart';

final adminApp = FirebaseAdminApp.initializeApp(
  'your-project-id',
  Credential.fromServiceAccountParams(
    clientId: 'your-client-id',
    privateKey: 'your-private-key',
    email: 'your-client-email',
  ),
);

final firestore = Firestore(adminApp);

final auth = Auth(adminApp);

final messaging = Messaging(adminApp);

定义HTTP函数

使用@HTTPFunction()来定义HTTP函数。

import 'package:dart_firebase_admin/dart_firebase_admin.dart';
import 'package:dart_firebase_functions/dart_firebase_functions.dart';
import 'package:shelf/shelf.dart';

FirebaseAdminApp initializeAdminApp() => adminApp;

@HTTPFunction()
Future<Response> hello(Request request) async => Response.ok('Hello, World!');

然后运行builder_runner生成代码：

dart pub run build_runner build -d

你将得到类似如下的代码：

// GENERATED CODE - DO NOT MODIFY BY HAND

import 'package:dart_firebase_functions/dart_firebase_functions.dart';
import 'package:functions_framework/serve.dart';
import 'package:server/functions.dart' as function_library;

Future<void> main(List<String> args) async {
  final app = function_library.initializeAdminApp();
  FirebaseFunctions.initialize(app);
  await serve(args, _nameToFunctionTarget);
}

FunctionTarget? _nameToFunctionTarget(String name) => switch (name) {
      'hello' => FunctionTarget.http(
          function_library.hello,
        ),
      _ => null
    };

定义Cloud Firestore触发的函数

为了定义一个由Cloud Firestore文档创建触发的函数，使用@OnDocumentCreated并传递相应的参数。

import 'package:dart_firebase_admin/dart_firebase_admin.dart';
import 'package:dart_firebase_functions/dart_firebase_functions.dart';
import 'package:functions_framework/functions_framework.dart';

FirebaseAdminApp initializeAdminApp() => adminApp;

@OnDocumentCreated('todos/{todoId}')
Future<void> oncreatetodo(
  ({String todoId}) params,
  QueryDocumentSnapshot snapshot,
  RequestContext context,
) async {
  context.logger.debug('todoId: ${params.todoId}');
  final data = snapshot.data();
  final title = data?['title'] as String?;
  await snapshot.ref.update({'title': '$title from server!'});
}

也可以通过嵌套文档创建触发。

@OnDocumentCreated('todos/{todoId}/logs/{logId}')
Future<void> oncreatelog(
  ({String todoId, String logId}) params,
  QueryDocumentSnapshot snapshot,
  RequestContext context,
) async {
  final todoId = params.todoId;
  final logId = params.logId;
  final data = snapshot.data();
  context.logger.debug('todoId: $todoId');
  context.logger.debug('logId: $logId');
  context.logger.debug('data: $data');
}

然后运行builder_runner生成代码：

dart pub run build_runner build -d

你将得到类似如下的代码：

// GENERATED CODE - DO NOT MODIFY BY HAND

import 'package:dart_firebase_functions/dart_firebase_functions.dart';
import 'package:functions_framework/serve.dart';
import 'package:server/functions.dart' as function_library;

Future<void> main(List<String> args) async {
  final app = function_library.initializeAdminApp();
  FirebaseFunctions.initialize(app);
  await serve(args, _nameToFunctionTarget);
}

FunctionTarget? _nameToFunctionTarget(String name) => switch (name) {
      'oncreatetodo' => FunctionTarget.cloudEventWithContext((event, context) {
          const pathPattern = 'todos/{todoId}';
          final documentIds =
              FirestorePathParser(pathPattern).parse(event.subject!);
          final data = QueryDocumentSnapshotBuilder(event).fromCloudEvent();
          return function_library.oncreatetodo(
            (todoId: documentIds['todoId']!),
            data.snapshot,
            context,
          );
        }),
      'oncreatelog' => FunctionTarget.cloudEventWithContext((event, context) {
          const pathPattern = 'todos/{todoId}/logs/{logId}';
          final documentIds =
              FirestorePathParser(pathPattern).parse(event.subject!);
          final data = QueryDocumentSnapshotBuilder(event).fromCloudEvent();
          return function_library.oncreatelog(
            (todoId: documentIds['todoId']!, logId: documentIds['logId']!),
            data.snapshot,
            context,
          );
        }),
      _ => null
    };

示例代码

void main() {
  print('Hello, World!');
}