OpenAI TTS chunked transfer streaming dart (not working on web)

open_ai_api.dart

import 'dart:convert';

import 'package:universal_io/io.dart';
import 'package:http/http.dart' as http;

import 'dart:typed_data';

const _kOpenAiApiKey = 'sk-QDU...';

abstract interface class OpenAiApi {
  Future<Uint8List> textToSpeech(
    String text, {
    String? voice,
    double? speed,
  });
  Future<Stream<List<int>>> textToSpeechStream(
    String text, {
    String? voice,
    double? speed,
  });
}

class OpenAiApiImpl implements OpenAiApi {
  @override
  Future<Uint8List> textToSpeech(
    String text, {
    String? voice,
    double? speed,
  }) async {
    try {
      final response = await http.post(
        Uri.parse('https://api.openai.com/v1/audio/speech'),
        headers: {
          'Authorization': 'Bearer $_kOpenAiApiKey',
          HttpHeaders.contentTypeHeader: 'application/json',
        },
        body: json.encode({
          'model': 'tts-1',
          'voice': voice ?? 'nova',
          'input': text,
          'speed': speed?.toString() ?? '1',
        }),
      );

      if (response.statusCode != 200) {
        throw Exception(
          'Error generating speech: '
          '${response.statusCode} - ${response.reasonPhrase} \n '
          '${response.body}',
        );
      } else {
        logger.i('Audio generated successfully');
        return response.bodyBytes;
      }
    } catch (e, s) {
      logger.e(e);
      logger.e(s);
    }

    return Uint8List(0);
  }

  @override
  Future<Stream<List<int>>> textToSpeechStream(
    String text, {
    String? voice,
    double? speed,
  }) async {
    try {
      final request = http.Request(
        'POST',
        Uri.parse('https://api.openai.com/v1/audio/speech'),
      );
      request.headers.addAll({
        'Authorization': 'Bearer $_kOpenAiApiKey',
        // HttpHeaders.transferEncodingHeader: 'chunked',
        HttpHeaders.contentTypeHeader: 'application/json',
      });
      request.body = json.encode({
        'model': 'tts-1',
        'voice': voice ?? 'nova',
        'input': text,
        'speed': speed?.toString() ?? '1',
      });
      final streamedResponse = await request.send();

      if (streamedResponse.statusCode != 200) {
        final response = await http.Response.fromStream(streamedResponse);
        throw Exception(
          'Error generating speech: '
          '${response.statusCode} - ${response.reasonPhrase} \n '
          '${response.body}',
        );
      } else {
        logger.i('Audio generated successfully');
        return streamedResponse.stream.asBroadcastStream();
      }
    } catch (e, s) {
      logger.e(e);
      logger.e(s);
    }

    return const Stream.empty();
  }
}