如何让服务器发送事件在我的颤栗应用程序？

Question

我正试图在我的应用程序中以JSON的形式接收SSE数据。但是，不是获取数据，而是在我的控制台中得到以下重复的数字数组。

    I/flutter (17286): Received streamedResponse.statusCode:200
    I/flutter (17286): Received data:[100, 97, 116, 97, 58, 32, 123, 34, 109, 115, 103, 34, 58, 34, 84, 104, 105, 115, 32, 105, 115, 32, 109, 121, 32, 109, 101, 115, 115, 97, 103, 101, 34, 125, 10, 10]
    I/flutter (17286): Received data:[100, 97, 116, 97, 58, 32, 123, 34, 109, 115, 103, 34, 58, 34, 84, 104, 105, 115, 32, 105, 115, 32, 109, 121, 32, 109, 101, 115, 115, 97, 103, 101, 34, 125, 10, 10]

以下是服务器上SSE数据的样子

data: {"msg":"This is my message"}
data: {"msg":"This is my message"}
data: {"msg":"This is my message"}
    (repeated over and over)

这是颤振代码；

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

 class MyApp extends StatelessWidget {
 http.Client _client;

  MyApp() : super() {
         subscribe();
   }

  @override
    Widget build(BuildContext context) {
       return MaterialApp(
     title: 'Flutter SSE',
     home: Scaffold(
      appBar: AppBar(
      title: Text('Receive SSE Events'),
    ),
    body: Center(
      child: Text('Ready for events..'),
    ),
   ),
 );
}

subscribe() async {
  print("Subscribing..");
  try {
   _client = http.Client();

  var request = new http.Request("GET", Uri.parse("http://18.224.97.18:8080/connect"));
  request.headers["Cache-Control"] = "no-cache";
  request.headers["Accept"] = "text/event-stream";

  Future<http.StreamedResponse> response = _client.send(request);

  response.asStream().listen((streamedResponse) {
    print("Received streamedResponse.statusCode:${streamedResponse.statusCode}");
    streamedResponse.stream.listen((data) {
      print("Received data:$data");
    });

  });
} catch(e) {
  print("Caught $e");
  }
}

 unsubscribe() {
   _client.close();
      }
     }

我不知道为什么"print("Received data:$data")要在SSE流中提供数字数组而不是{"msg":"This is my message"}。

有人知道我为什么要得到这些数字而不是数据吗？

Answer 1

ByteStream是从streamedResponse.stream.listen()返回的data。要解码这个值，您可以像注释中提到的那样使用utf8.decode(data)。

Answer 2

对服务器发送的事件流数据使用sse包。它返回事件、id和数据的解析模型。