Regarding Flutter + Flutter Web packages not being recognized on pub.dev

[luanpotter]

I just uploaded a new version of the package audioplayers including the flutter web files.

However, pub does not like the web files:

See: https://pub.dev/packages/audioplayers#-analysis-tab-

Fix lib/audioplayers_web.dart. (-95.82 points)
Analysis of lib/audioplayers_web.dart failed with 11 errors, 2 hints, including:
line 3 col 8: Target of URI doesn't exist: 'dart:web_audio'.
line 8 col 7: Undefined class 'AudioContext'.
line 8 col 32: The function 'AudioContext' isn't defined.
line 17 col 3: Undefined class 'AudioBuffer'.
line 18 col 3: Undefined class 'AudioBufferSourceNode'.

I also find it weird that I have to add the audioplayer_web.dart file inside the lib folder. All other platforms have dedicated folders outside the lib folder. This file is the implementation for web, should be placed on a web folder outside the lib folder, just like ios, android and macos. However when I do that, I cannot properly run the example app on web.

Can you give me some directions on how to proceed? Having such a low score on pub is not desirable, I'm sure there is a way to configure everything properly.

[isoos]

@luanpotter: thanks for reporting this, seems like an edge case in Flutter web + dartanalyzer, we'll need to dig into it what's going on.

I also find it weird that I have to add the audioplayer_web.dart file inside the lib folder.

Could you please link where this is recommended?

[luanpotter]

Hi @isoos , thanks for looking into this!

So I'm in contact with Mariam from Google. I got some instructions and I was following this article. Mostly it suggests creating a separated package, but since I'm the owner of the original audioplayers, I thought I might do it on the same (the same way all other platforms reside on the same plugin, different implementation folders).

The article directs us to add a <plugin>_web.dart file inside the lib folder. So that is my confusion. Also I tried adding a web folder outside of lib and adding the file there, but then on the example app for web I cannot make it properly import that file.

[isoos]

Maybe the author @hterkelsen can comment on this? Or some another official Flutter channel: https://flutter.dev/community

I am not aware what the official layout recommendation on this is, and I couldn't find example repositories with similar layouts. If there is anything we shall change in the analysis or suggestions, I'm happy to help with that, but I cannot recommend on how Flutter (esp. the new web platform) should be used.

[harryterkelsen]

Unfortunately, the only web-specific dart: libraries available in Flutter are dart:html, dart:js and dart:js_util. You can use package:js to create JS-interop classes for the dart:web_audio classes you are using and most likely only have to change the import in audioplayers_web.dart from dart:web_audio to your library containing your JS-interop classes.

As for layout: you could create an web/ directory which would be another package which just has the web-specific code. Unfortunately, you will also need to add stub Android and iOS folders in your web plugin... The reason that you can't just have a web/ folder containing just the Dart files is that those files wouldn't be able to be imported since they wouldn't be inside of a Dart package.

[luanpotter]

@hterkelsen, thanks for your input.

Unfortunately, the only web-specific dart: libraries available in Flutter are dart:html, dart:js and dart:js_util

I'm not sure I follow, I am using dart:web_audio and tested in Flutter web and it worked. It is certainly available. It just doesn't work on pub.

About the layout, I understand it could be technical difficult, and I'm certainly ok with keeping audioplayers_web.dart inside, but I propose as a suggestion the structure I mentioned as I think it's more clear and more in-line with what my expectations are.

[isoos]

I'm not sure I follow, I am using dart:web_audio and tested in Flutter web and it worked. It is certainly available. It just doesn't work on pub.

@luanpotter: Could you please run the following commands in your package directory and copy their output here:

flutter --version
flutter analyze
[path-to-flutter-sdk]/bin/cache/dart-sdk/bin/dartanalyzer lib/

I have a fear that we are getting another edge case where the Flutter-included SDK slightly differs from the APIs provided by Flutter SDK. A prior bug on that was this: flutter/flutter#23664

[luanpotter]

There you have it:

[luan@aurora audioplayers]$ flutter --version
Flutter 1.14.7-pre.83 • channel master • https://github.com/flutter/flutter.git
Framework • revision e10df3c1a6 (13 hours ago) • 2020-02-01 11:23:01 +0800
Engine • revision e625e174c5
Tools • Dart 2.8.0 (build 2.8.0-dev.6.0 5ae5aff640)

[luan@aurora audioplayers]$ flutter analyze
Running "flutter pub get" in audioplayers...                        0.7s
Analyzing audioplayers...                                               

   info • 'seekCompleteHandler' is deprecated and shouldn't be used • example/lib/main.dart:228:27 • deprecated_member_use
  error • Target of URI doesn't exist: 'dart:web_audio' • lib/audioplayers_web.dart:3:8 • uri_does_not_exist
  error • Undefined class 'AudioContext' • lib/audioplayers_web.dart:8:7 • undefined_class
  error • The function 'AudioContext' isn't defined • lib/audioplayers_web.dart:8:32 • undefined_function
  error • Undefined class 'AudioBuffer' • lib/audioplayers_web.dart:17:3 • undefined_class
  error • Undefined class 'AudioBufferSourceNode' • lib/audioplayers_web.dart:18:3 • undefined_class
  error • Undefined class 'GainNode' • lib/audioplayers_web.dart:19:3 • undefined_class
  error • Undefined class 'AudioBuffer' • lib/audioplayers_web.dart:21:18 • undefined_class
  error • The name 'AudioBuffer' isn't a type so it can't be used as a type argument • lib/audioplayers_web.dart:85:15 • non_type_as_type_argument
  error • The name 'AudioBuffer' isn't a type so it can't be used as a type argument • lib/audioplayers_web.dart:98:10 • non_type_as_type_argument
  error • Undefined class 'AudioBuffer' • lib/audioplayers_web.dart:105:11 • undefined_class
  error • Undefined class 'AudioBuffer' • lib/audioplayers_web.dart:116:11 • undefined_class
   info • The value of the local variable 'isLocal' isn't used • lib/audioplayers_web.dart:134:22 • unused_local_variable
   info • This function has a return type of 'Future<dynamic>', but doesn't end with a return statement • test/audioplayers_test.dart:8:36 • missing_return

14 issues found. (ran in 17.3s)

[luan@aurora audioplayers]$ /home/luan/softwares/flutter/bin/cache/dart-sdk/bin/dartanalyzer lib/
Analyzing lib...
  error • Target of URI doesn't exist: 'dart:web_audio'. • lib/audioplayers_web.dart:3:8 • uri_does_not_exist
  error • Undefined class 'AudioContext'. • lib/audioplayers_web.dart:8:7 • undefined_class
  error • The function 'AudioContext' isn't defined. • lib/audioplayers_web.dart:8:32 • undefined_function
  error • Undefined class 'AudioBuffer'. • lib/audioplayers_web.dart:17:3 • undefined_class
  error • Undefined class 'AudioBufferSourceNode'. • lib/audioplayers_web.dart:18:3 • undefined_class
  error • Undefined class 'GainNode'. • lib/audioplayers_web.dart:19:3 • undefined_class
  error • Undefined class 'AudioBuffer'. • lib/audioplayers_web.dart:21:18 • undefined_class
  error • The name 'AudioBuffer' isn't a type so it can't be used as a type argument. • lib/audioplayers_web.dart:85:15 • non_type_as_type_argument
  error • The name 'AudioBuffer' isn't a type so it can't be used as a type argument. • lib/audioplayers_web.dart:98:10 • non_type_as_type_argument
  error • Undefined class 'AudioBuffer'. • lib/audioplayers_web.dart:105:11 • undefined_class
  error • Undefined class 'AudioBuffer'. • lib/audioplayers_web.dart:116:11 • undefined_class
  hint • The value of the local variable 'isLocal' isn't used. • lib/audioplayers_web.dart:134:22 • unused_local_variable
11 errors and 1 hint found.

Which seems to indicate that the dart:web_audio package does not exist. However if you go to the example folder and run the project on web, it will compile, run and work successfully.

[isoos]

@luanpotter: This looks looks like a Flutter-internal bug: the Flutter analyzer should recognize the missed libraries. Could you please open a bug in https://github.com/flutter/flutter/issues, copy the details over there, and also reference the bug here? Thank you! (I'll have proper time to do this on Monday if you can't do it until then.)

[isoos]

@luanpotter: It looks like dart:web_audio is not yet officially supported by Flutter, and there is a discussion on how it should be done in the long term. See: flutter/flutter#49849

[jonasfj]

It's not clear this is a bug in pub.dev

[chipweinberger]

I'm hitting the same error. I am trying to add Web support to https://github.com/chipweinberger/flutter_pcm_sound

I don't want to use a federated structure if I don't have to.

Can someone upload a example repo with 'dart:web_audio' without a federated repo? Is this even possible?