Flutter - 如何实现网络服务发现

Question

我想发现正在运行暴露于本地网络的指定服务的设备，但我不知道如何做。例如，我想要运行服务“_googlecast._tcp.”的设备的本地 IP 地址和端口号。

Flutter 有什么办法可以实现这一点吗？

提前致谢

Answer 1

检查多播 DNS 包：一个 Dart 包，用于通过多播 DNS (mDNS)、Bonjour 和 Avahi 进行服务发现。本质上，创建一个 mDNS 客户端并获取该服务的 PTR 记录，如下所示：

const String name = '_googlecast._tcp.local';
  final MDnsClient client = MDnsClient();
  await client.start();
  // Get the PTR recod for the service.
  await for (PtrResourceRecord ptr in client
      .lookup<PtrResourceRecord>(ResourceRecordQuery.serverPointer(name))) {
    // Use the domainName from the PTR record to get the SRV record,
    // which will have the port and local hostname.
    // Note that duplicate messages may come through, especially if any
    // other mDNS queries are running elsewhere on the machine.
    await for (SrvResourceRecord srv in client.lookup<SrvResourceRecord>(
        ResourceRecordQuery.service(ptr.domainName))) {
      // Domain name will be something like "io.flutter.example@some-iphone.local._dartobservatory._tcp.local"
      final String bundleId =
          ptr.domainName; //.substring(0, ptr.domainName.indexOf('@'));
      print('Dart observatory instance found at '
          '${srv.target}:${srv.port} for "$bundleId".');
    }
  }
  client.stop();

  print('Done.');