Cannot build web app with pure Dart

[kaboc]

Describe the bug

Building a web app not using Flutter fails due to the universal_io package that is currently lacking support for web.

To Reproduce

Steps to reproduce the behavior:

1. Create a project with dart create -t web.
2. Run dart pub add supabase and dart pub get to start using the supabase package.
3. Prepare to use Supabase by calling the SupabaseClient constructor.
4. Run the app by webdev serve.
5. See the warnings printed in the console.
6. Open localhost:8080 in a browser.

main.dart should look like this:

import 'dart:html';

import 'package:supabase/supabase.dart';

void main() {
  SupabaseClient(
    'Your Supabase URL',
    'Your Supabase Key',
  );

  querySelector('#output')?.text = 'Your Dart app is running.';
}

Expected behavior

There is no warning during a build, and "Your Dart app is running." is shown in the browser.

Screenshots

N/A

Version (please complete the following information):

└── supabase 1.11.5
    ├── functions_client 1.3.2
    ├── gotrue 1.12.2
    ├── postgrest 1.5.1
    ├── realtime_client 1.2.2
    ├── storage_client 1.5.2

Additional context

[WARNING] build_web_compilers:entrypoint on web/main.dart: Skipping compiling bug|web/main.dart with ddc because some of its
transitive libraries have sdk dependencies that not supported on this platform:

universal_io|lib/src/_exports_in_vm.dart
universal_io|lib/src/internet_address.dart
universal_io|lib/src/http_client.dart

[kaboc]

How about removing the dependency on universal_io if it is not heavily used? It will make the supabase package less subject to external changes.

As far as I see,

• gotrue uses SocketException
• storage_client uses SocketException and File

It may be possible to replace File with XFile.

[kaboc]

Related issue: dint-dev/universal_io#41

[Vinzent03]

I'm unsure on how to replace the SocketException. Does everything work except that warning?

[kaboc]

Does everything work except that warning?

main.dart.js is not created due to the dependency on universal_io. I cannot start the web app at all. If you have to see what actually happens, please try building an app, following the steps I wrote earlier.

I was thinking SocketException was reimplementation in universal_io. However, having looked at the source code, it looks like the SocketException itself from dart:io via universal_io if I'm not wrong. It means the package depends on dart:io, whether the app is for mobile / desktop or for web. It seems like the cause of the issue.

I was able to build my blog site made with Dart + Jaspr + Supabase when I was using supabase 1.4.0. I'm not sure about other versions between that version and the latest. Investigating how universal_io was handling SocketException in the past would probably be a way to find a solution.