Dart错误：错误：当前Dart运行时不支持dart：mirrors的导入 [英] Dart Error: error: import of dart:mirrors is not supported in the current Dart runtime

问题描述

我目前正在尝试使用Flutter编写一些移动代码。我正在尝试使用gcloud库dart将数据发布/订阅到GCP Cloud Pub / Sub。以下是main.dart的代码：

  import‘dart：io’; 
作为 auth导入 package：googleapis_auth / auth_io.dart； 
导入 package：http / http.dart为http； 
导入 package：gcloud / db.dart； 
 import‘package：gcloud / storage.dart’; 
 
 
导入 package：gcloud / pubsub.dart； 
导入 package：gcloud / service_scope.dart为ss； 
导入 package：gcloud / src / datastore_impl.dart作为datastore_impl； 
 
 Future< int> main（）async {
 
 //从文件中读取服务帐户凭据。 
 var jsonCredentials = new File（’path / file.json’）。readAsStringSync（）; 
 var凭证=新的auth.ServiceAccountCredentials.fromJson（jsonCredentials）; 
 
 //使用服务帐户凭据获取经过HTTP身份验证的客户端。 
 var范围= [] 
 ..addAll（PubSub.SCOPES）; 
 var client = await auth.clientViaServiceAccount（凭证，作用域）; 
 
 
 //实例化对象以访问Cloud Datastore，Cloud Storage 
 //和Cloud Pub / Sub API。 
 var pubsub = new PubSub（client，'project-name'）; 
 ss.fork（（）{
 //在新服务范围中注册服务
 registerPubSubService（pubsub）; 
 
 //使用这些服务运行应用程序。
}）; 
 
 var topic = await pubsub.createTopic（'flutter'）; 
等待topic.publishString（'coba publish dr flutter'）; 
 
 var订阅= 
等待pubsub.createSubscription（'sub_flutter'，'flutter'）; 
 var pullEvent =等待subscription.pull（）; 
 print（pullEvent.message.asString）; 
等待pullEvent.acknowledge（）; 
 
返回0; 
} 
  

这是pubspec.yaml上的依赖项：

 依赖性：
抖动：
 sdk：抖动
 
 googleapis：^ 0.54.0 
 googleapis_beta：^ 0.49.0 
 googleapis_auth：^ 0.2.10 
 gcloud：^ 0.6.3 
 
  

尝试调试代码时，出现以下错误：

 启动lib\ vivo 1918上的main.dart在调试模式下... 
构建build\app\outputsapk\debug\app-debug.apk。 
 E / flutter（20586）：[错误：flutter / shell / common / shell.cc（178）] Dart错误：错误：当前Dart运行时中不支持dart：mirrors的导入/ flutter（20586）：[错误：flutter / shell / common / engine.cc（188）]无法准备运行隔离。 
 E / flutter（20586）：[错误：flutter / shell / common / engine.cc（127）]引擎未准备好并启动隔离。 
 E / flutter（20586）：[错误：flutter / shell / common / shell.cc（407）]无法使用配置启动引擎。 
  

解决方案

不幸的是dart的glcoud软件包与flutter不兼容（或网络）由于使用了镜像包。
https://github.com/dart-lang/gcloud/issues/新建

我还可以检查 googleapis 包，其中包含可能符合您需求的pub / sub实现。
https：// pub.dev/documentation/googleapis/latest/googleapis.pubsub.v1/googleapis.pubsub.v1-library.html 。 （由glcoud软件包使用）

I'm currently trying to make some mobile code with Flutter. I'm trying to publish/subscribe data to GCP Cloud Pub/Sub using gcloud library dart. Here is the code for the main.dart:

import 'dart:io';
import 'package:googleapis_auth/auth_io.dart' as auth;
import 'package:http/http.dart' as http;
import 'package:gcloud/db.dart';
import 'package:gcloud/storage.dart';


import 'package:gcloud/pubsub.dart';
import 'package:gcloud/service_scope.dart' as ss;
import 'package:gcloud/src/datastore_impl.dart' as datastore_impl;

Future<int> main() async {

  // Read the service account credentials from the file.
var jsonCredentials = new File('path/file.json').readAsStringSync();
var credentials = new auth.ServiceAccountCredentials.fromJson(jsonCredentials);

// Get an HTTP authenticated client using the service account credentials.
var scopes = []    
    ..addAll(PubSub.SCOPES);
var client = await auth.clientViaServiceAccount(credentials, scopes);


// Instantiate objects to access Cloud Datastore, Cloud Storage
// and Cloud Pub/Sub APIs.
var pubsub = new PubSub(client, 'project-name');
ss.fork(() {
  // register the services in the new service scope.
  registerPubSubService(pubsub);

  // Run application using these services.
});

var topic = await pubsub.createTopic('flutter');
await topic.publishString('coba publish dr flutter');

var subscription =
    await pubsub.createSubscription('sub_flutter', 'flutter');
var pullEvent = await subscription.pull();
print(pullEvent.message.asString);
await pullEvent.acknowledge();

  return 0;
}

Here are the denpendencies on the pubspec.yaml:

dependencies:
  flutter:
    sdk: flutter

  googleapis: ^0.54.0
  googleapis_beta: ^0.49.0
  googleapis_auth: ^0.2.10
  gcloud: ^0.6.3

When trying to debug the code I get the following errors:

Launching lib\main.dart on vivo 1918 in debug mode...
Built build\app\outputs\apk\debug\app-debug.apk.
E/flutter (20586): [ERROR:flutter/shell/common/shell.cc(178)] Dart Error: error: import of dart:mirrors is not supported in the current Dart runtime
E/flutter (20586): [ERROR:flutter/shell/common/engine.cc(188)] Could not prepare to run the isolate.
E/flutter (20586): [ERROR:flutter/shell/common/engine.cc(127)] Engine not prepare and launch isolate.
E/flutter (20586): [ERROR:flutter/shell/common/shell.cc(407)] Could not launch engine with configuration.

解决方案

Unfortunately the glcoud package for dart is not compatible with flutter (or web) due to the mirror package.

I suggest you to open an issue on the github repository about supporting gcloud pub/sub on flutter. https://github.com/dart-lang/gcloud/issues/new

I can also check the googleapis package which has a pub/sub implementation that might fit your needs. https://pub.dev/documentation/googleapis/latest/googleapis.pubsub.v1/googleapis.pubsub.v1-library.html. (use by glcoud package)

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