Error: Dart library 'dart:html' is not available on this platform.

[MichealReed]

Error:

Error: Dart library 'dart:html' is not available on this platform.
import 'dart:html' show Blob, FormData, UrlSearchParams;
       ^
Info: The unavailable library 'dart:html' is imported through these packages:

    package:supabase_edge_functions_example => package:dart_openai => package:fetch_client => package:fetch_api => dart:html

Any edge function that references packages that nest dart:html should trigger this.

https://github.com/anasfik/openai uses https://github.com/Zekfad/fetch_client uses https://github.com/Zekfad/fetch_api

Example:

create new edge function

dart pub add fetch_api

import 'package:supabase_functions/supabase_functions.dart';
import 'package:fetch_api/fetch_api.dart' as api;

void main() {
  SupabaseFunctions(fetch: (request) {
    void main() async {
      // Simple cors request
      final response = await fetch(
        Resource('https://api.restful-api.dev/objects/1'),
      );

      print(await response.text());
    }

    return Response("Hello from Supabase Edge Functions!");
  });
}

This all makes sense in that dart_edge has created a custom fetch client, but some packages use custom fetch clients as well. I am attempted to get the dart_openai package to work, which uses conditional importing of the referenced fetch package here:

https://github.com/anasfik/openai/blob/aa42ccee89c0fef5b4102eceee11d28890d0bcdb/lib/src/core/networking/client.dart

if I remove the conditional import so that it only sees the http_client_io, the package will compile as an edge function. If the conditional import is present based on dart.library.io, or even refactoring the imports to look like this

import 'package:dart_openai/src/core/utils/http_client_io.dart'
    if (dart.library.js) 'package:dart_openai/src/core/utils/http_client_web.dart'
    if (dart.library.io) 'package:dart_openai/src/core/utils/http_client_io.dart';

I run into the error referenced above as the import takes the web path. I am not sure if this is directly a dart_edge issue, but thought I would start here as it is likely similar imports / nesting of dart:html will be found across the package ecosystem.

[Ehesp]

Unfortunately the Zekfad/fetch_api package is assuming the user is running on the web environment, not a JS one. I'll take a look at the openai package but I'm not sure there's much we can do.

[Ehesp]

Hmm, replacing this:

fetch.FetchClient createClient() =>
    fetch.FetchClient(mode: fetch.RequestMode.cors);

with

import 'package:edge_http_client/edge_http_client.dart';

http.Client createClient() => EdgeHttpClient();

Could do the trick.

[MichealReed]

The problem is that the code execution follows the JS path for building edge functions, if it followed the normal io path it seems your override would work. If I remove the web dependency from the lib the edge function compiles fine.

[MichealReed]

After forcing the import path, or modifying the package to use

import 'package:edge_http_client/edge_http_client.dart';

http.Client createClient() => EdgeHttpClient();

as suggested, I now see the same issue as in https://github.com/invertase/dart_edge/issues/34. Will close this to resolve there.