从Flutter应用程序连接到本地Firebase函数模拟器时出错

Question

在用本地Firebase函数模拟器作为我的后端设置了我的项目，并从我的Android模拟器调用了我的Firebase onCall函数后，我收到了一条非常没有信息的错误消息PlatformException(functionsError, Cloud function failed with exception., {code: INTERNAL, details: null, message: INTERNAL})。下面的完整错误消息：

E/flutter (20862): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: PlatformException(functionsError, Cloud function failed with exception., {code: INTERNAL, details: null, message: INTERNAL})
E/flutter (21445): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
E/flutter (21445): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
E/flutter (21445): <asynchronous suspension>
E/flutter (21445): #2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
E/flutter (21445): #3      MethodChannelCloudFunctions.callCloudFunction (package:cloud_functions_platform_interface/src/method_channel_cloud_functions.dart:43:15)
E/flutter (21445): #4      HttpsCallable.call (package:cloud_functions/src/https_callable.dart:33:12)
E/flutter (21445): #5      ApiService.loadUserLessonsByLessonIds (package:kim/services/api.dart:28:21)
E/flutter (21445): #6      MapScreen.build.<anonymous closure> (package:kim/screens/map.dart:170:34)
E/flutter (21445): #7      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:779:19)
E/flutter (21445): #8      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:862:36)
E/flutter (21445): #9      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (21445): #10     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:504:11)
E/flutter (21445): #11     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:282:5)
E/flutter (21445): #12     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:217:7)
E/flutter (21445): #13     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:475:9)
E/flutter (21445): #14     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
E/flutter (21445): #15     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:122:9)
E/flutter (21445): #16     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
E/flutter (21445): #17     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:120:18)
E/flutter (21445): #18     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:106:7)
E/flutter (21445): #19     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter (21445): #20     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (21445): #21     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (21445): #22     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (21445): #23     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (21445): #24     _rootRunUnary (dart:async/zone.dart:1196:13)
E/flutter (21445): #25     _CustomZone.runUnary (dart:async/zone.dart:1085:19)
E/flutter (21445): #26     _CustomZone.runUnaryGuarded (dart:async/zone.dart:987:7)
E/flutter (21445): #27     _invoke1 (dart:ui/hooks.dart:275:10)
E/flutter (21445): #28     _dispatchPointerDataPacket (dart:ui/hooks.dart:184:5)
E/flutter (21445): 

服务器代码index.ts:

import * as functions from 'firebase-functions'
interface LoadUserLessonsData {
lessonIds: string[]
}
export const loadUserLessons = functions.https.onCall((data: LoadUserLessonsData, context) => {
const uid = context.auth?.uid
const ids = data.lessonIds
console.log(uid, ids)
})

运行firebase emulators:start --only functions:后的服务器控制台窗口

...
+  functions[loadUserLessons]: http function initialized (http://localhost:5001/project-name/us-central1/loadUserLessons).
...
┌───────────┬────────────────┬─────────────────────────────────┐
│ Emulator  │ Host:Port      │ View in Emulator UI             │
├───────────┼────────────────┼─────────────────────────────────┤
│ Functions │ localhost:5001 │ http://localhost:4000/functions │
└───────────┴────────────────┴─────────────────────────────────┘

客户端应用程序代码api.dart:

import 'dart:io';
import 'package:cloud_functions/cloud_functions.dart';
import 'package:myapp/services/config.dart';
class ApiService {
static final ApiService _apiService = ApiService._internal();
static final _functions = CloudFunctions.instance;
ApiService._internal();
factory ApiService() {
init();
return _apiService;
}
static void init() {
// 10.0.2.2 is the special IP address to connect to the 'localhost' of the host computer from an Android emulator.
final origin = Platform.isAndroid ? 'http://10.0.2.2:5001' : 'http://localhost:5001';
_functions.useFunctionsEmulator(origin: origin);
}
static Future<dynamic> loadUserLessons(List<String> lessonIds) {
final HttpsCallable callable = _functions.getHttpsCallable(
functionName: 'loadUserLessons',
);
return callable.call({
'lessonIds': lessonIds,
});
}
}

如何正确设置Flutter应用程序以连接到本地模拟器？

应该注意的是，无论模拟器是否正在运行，错误消息都是相同的。模拟器也没有在控制台日志中注册任何事件。然而，当模拟器正在运行时，向功能端点发送自定义请求(例如通过类似"RESTApiClient"的Android应用程序(确实会使模拟器做出反应。

这意味着问题仅存在于Flutter代码(mine或cloud_functionsFlutter包(中。至少，到目前为止，这是我的结论。

Answer 1

幸运的是，我设置了Crashlytics，它收到了更详细的错误消息，其中一条是：

CLEARTEXT communication to 10.0.2.2 not permitted by network security policy

这让我想到了这个Stackloverflow问题和Ashish John的评论：

OkHttp:<--HTTP失败：java.net.UnnknownService异常：网络安全策略不允许CLEARTEXT与10.0.2.2通信

你可以你的android：usesCleartextTraffic="true"在清单文件的"Application"标记中。如果您的API/链接不支持https&您正在使用"Android P"或更高版本。

阅读有关android:usesCleartextTraffic的更多信息https://developer.android.com/guide/topics/manifest/application-element

指示应用程序是否打算使用明文网络流量，如明文HTTP针对API等级27或更低的应用程序的默认值是"；真"；。以API 28级或更高级别为目标的应用程序默认为；false">。

换句话说，如果您的Android模拟器运行的是Android API 28级或更高级别，则需要将android:usesCleartextTraffic="true"添加到应用程序的AndroidManifest.xml中的<application>标记中

现在我们需要允许Android模拟器和Firebase功能模拟器之间的流量，Ahmed Ghrib解决了这个问题。

OkHttp:<--HTTP失败：java.net.UnnknownService异常：网络安全策略不允许CLEARTEXT与10.0.2.2通信

创建一个文件network_security_config.xml，并使用以下代码将其放置在[PROJECT]/android/app/src/main/res/xml中：

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<domain-config cleartextTrafficPermitted="true">
<domain>10.0.2.2</domain>
</domain-config>
</network-security-config>

这是对Ahmed Ghrib答案的修改版本，目的是限制明文流量只能在Android模拟器和Firebase函数模拟器之间使用。