flutter 在新进程中运行 firebase 存储和 firestore 或隔离导致绑定问题

Question

我正在构建一个用户上传徽标的应用程序，我已经在 firebase 存储中激活了调整器扩展。因此，所有上传的图片都将被替换为具有相同参考但以“_600x600.png”而不是“.png”结尾的调整大小的图片。

考虑到在上传功能中，如果我等待原始文件上传，它不会保证新的“600x600.png”完成上传。

我的最终目标是获取新文件的下载 URL。我最好的方法是从客户端运行一个隔离函数，它尝试获取新的文件路径，如果没有成功（因为上传调整大小的文件可能需要一段时间），它将等待 1 秒，然后重试等等...

因此，如果我在“新”过程中实现它，我不应该看到任何伤害。

这是我所做的：

1. 全局上传函数：

   Future updateResizedProfileUrl2(Map<String, dynamic> args) async {
     /// Updating profile cover and logo images urls as individual process
     /// imageType: logo, cover
     String imageType = args['type'];
     print('got into update function');
     await Firebase.initializeApp(
       options: DefaultFirebaseOptions.currentPlatform,
     );
   
     FirebaseFirestore _fs = FirebaseFirestore.instance;
     FirebaseStorage _fst = FirebaseStorage.instance;
     while (true) {
       Reference fileRef =
           _fst.ref(profileStorageDir).child('${imageType}_600x600.png');
       try {
         print('checking fileref $fileRef');
         final refStr = await fileRef.getDownloadURL();
         print('got url $refStr');
         _fs.collection(settingsCollection).doc('profile').update(
           {'media.$imageType': refStr},
         );
         print('updating media strrefStr');
         return;
       } catch (e) {
         print('waaiting....');
         print(e);
         sleep(const Duration(seconds: 2));
       }
     }
   }
   

   2. 这是我的主要上传功能

   MyClass... {
     Future<void> uploadLogoImage(File image) async {
       Reference ref = _fst.ref(profileStorageDir).child('logo.png');
       await ref.putFile(image);
       Map<String, dynamic> args = {
         'type': 'logo',
       };
       print('sent update logo');
       compute(updateResizedProfileUrl2, args);
     }
   }
   

   但这不起作用，出现以下错误：

   ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Binding has not yet been initialized.
   E/flutter (23103): The "instance" getter on the ServicesBinding binding mixin is only available once that binding has been initialized.
   E/flutter (23103): Typically, this is done by calling "WidgetsFlutterBinding.ensureInitialized()" or "runApp()" (the latter calls the former). Typically this call is done in the "void main()" method. The "ensureInitialized" method is idempotent; calling it multiple times is not harmful. After calling that method, the "instance" getter will return the binding.
   E/flutter (23103): In a test, one can call "TestWidgetsFlutterBinding.ensureInitialized()" as the first line in the test's "main()" method to initialize the binding.
   E/flutter (23103): If ServicesBinding is a custom binding mixin, there must also be a custom binding class, like WidgetsFlutterBinding, but that mixes in the selected binding, and that is the class that must be constructed before using the "instance" getter.
   E/flutter (23103): #0      BindingBase.checkInstance.<anonymous closure> (package:flutter/src/foundation/binding.dart:284:9)
   E/flutter (23103): #1      BindingBase.checkInstance (package:flutter/src/foundation/binding.dart:366:6)
   E/flutter (23103): #2      ServicesBinding.instance (package:flutter/src/services/binding.dart:54:54)
   E/flutter (23103): #3      BasicMessageChannel.binaryMessenger (package:flutter/src/services/platform_channel.dart:166:45)
   E/flutter (23103): #4      BasicMessageChannel.send (package:flutter/src/services/platform_channel.dart:180:38)
   E/flutter (23103): #5      FirebaseCoreHostApi.initializeCore (package:firebase_core_platform_interface/src/pigeon/messages.pigeon.dart:201:23)
   E/flutter (23103): #6      MethodChannelFirebase._initializeCore (package:firebase_core_platform_interface/src/method_channel/method_channel_firebase.dart:29:54)
   E/flutter (23103): #7      MethodChannelFirebase.initializeApp (package:firebase_core_platform_interface/src/method_channel/method_channel_firebase.dart:73:13)
   E/flutter (23103): #8      Firebase.initializeApp (package:firebase_core/src/firebase.dart:43:47)
   E/flutter (23103): #9      updateResizedProfileUrl2 (package:appointments/providers/settings_mgr.dart:33:18)
   E/flutter (23103): #10     _IsolateConfiguration.applyAndTime.<anonymous closure> (package:flutter/src/foundation/_isolates_io.dart:108:21)
   E/flutter (23103): #11     Timeline.timeSync (dart:developer/timeline.dart:160:22)
   E/flutter (23103): #12     _IsolateConfiguration.applyAndTime (package:flutter/src/foundation/_isolates_io.dart:106:21)
   E/flutter (23103): #13     _spawn (package:flutter/src/foundation/_isolates_io.dart:127:67)
   E/flutter (23103): #14     _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:300:17)
   E/flutter (23103): #15     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:192:12)
   E/flutter (23103): 
   

   我已经初始化了 firebase，因为我需要它，而且我知道 isolate 与 main 具有不同的内存......

   写作：全局函数中的“WidgetsFlutterBinding.ensureInitialized()”也不起作用......

   我怎样才能实现上述目标？或者我如何解决它？

   谢谢！！

Answer 1

简而言之，您不能从以标准方式生成的 isolate 运行本机代码，而 firebase 存储插件依赖于本机代码。

您需要的是使用 https://pub.dev/packages/isolate_handler 或 https://pub.dev/packages/flutter_isolate 生成隔离。那些支持插件，但并非所有插件都可以工作。我可以确认 firebase 存储与 isolate_handler 一起工作

flutter 使用平台通道与本机代码进行通信，而 WidgetsBinding.ensureInitialized() 是使用这些通道所需要的，这就是您收到此错误的原因。

还有一个问题 https://github.com/firebase/flutterfire/issues/9790 阻止了 firebase 存储在隔离中正常工作，但最近得到修复