Velocity向Spigot发插件消息时onPluginMessageReceived无响应排查

我正在为Minecraft服务器集群开发Velocity插件，实现/screenshare <玩家>命令，将员工玩家和嫌疑玩家转移到录屏服务器。为了让仅部署在录屏服务器的Spigot插件区分两者角色，使用了Plugin Messaging Channel。目前Spigot向Velocity发消息能正常接收，但Velocity发消息给Spigot时，Spigot端的onPluginMessageReceived完全没反应。

已知Velocity仅在有在线玩家时才会发送消息，已经设置了2秒延迟执行代码，没用。Velocity日志显示消息发送成功，但Spigot端无任何日志输出。试过用Bungee频道替代自定义频道、延长延迟时间，都没解决。

Spigot端代码 #

@Override
public void onEnable() {
    getServer().getMessenger().registerOutgoingPluginChannel(this, "test:screenshare");
    getServer().getMessenger().registerIncomingPluginChannel(this, "test:screenshare", this);

    // 注册PlayerJoin事件
    getServer().getPluginManager().registerEvents(this, this);
}

@Override
public void onPluginMessageReceived(String channel, Player player, byte[] message) {
    if (!(channel.equals("test:screenshare"))) {
        getLogger().info("Wrong channel: " + channel);
        return;
    }

    new BukkitRunnable() {
        @Override
        public void run() {
            ByteArrayDataInput in = ByteStreams.newDataInput(message);
            String subchannel = in.readUTF();

            if (subchannel.equals("RoleUpdate")) {
                String stafferRole = in.readUTF();
                String stafferName = in.readUTF();
                String suspectRole = in.readUTF();
                String suspectName = in.readUTF();

                getLogger().info("Received roles: " + stafferRole + " for " + stafferName + " and " + suspectRole + " for " + suspectName);
            } else {
                getLogger().info("Subchannel not found: " + subchannel);
            }
        }
    }.runTaskLater(this, 40L);
}

Velocity端代码 #

频道定义：

public static final MinecraftChannelIdentifier IDENTIFIER = MinecraftChannelIdentifier.from("test:screenshare");

调用触发：执行Velocity端/ss命令时调用sendPluginMessage(staffer.getUsername(), suspect.getUsername(), "Staffer", "Suspect");

消息发送方法：

private void sendPluginMessage(String stafferName, String suspectName, String stafferRole, String suspectRole) {
        ByteArrayDataOutput out = ByteStreams.newDataOutput();

        out.writeUTF("RoleUpdate");
        out.writeUTF(stafferRole);
        out.writeUTF(stafferName);
        out.writeUTF(suspectRole);
        out.writeUTF(suspectName);

        Optional<Player> anyConnectedPlayer = proxy.getAllPlayers().stream().findAny();
        if (anyConnectedPlayer.isPresent()) {
            Optional<ServerConnection> connection = anyConnectedPlayer.get().getCurrentServer();
            if (connection.isPresent()) {
                connection.get().sendPluginMessage(IDENTIFIER, out.toByteArray());
                logger.info("Message sent to spigot, staffer name: " + stafferName + " (role: " + stafferRole + ") and suspect: " + suspectName + " (role: " + suspectRole + ")");
            } else {
                logger.warn("No connection was found for player: " + anyConnectedPlayer.get().getUsername());
            }
        } else {
            logger.warn("No players connected to send message to the spigot server.");
        }
    }

排查与解决步骤 #

• 修正消息目标服务器：当前代码是随机找一个在线玩家的服务器发送消息，但该玩家大概率不在录屏服务器上。直接定位录屏服务器发送：

  // 替换原来的玩家查找逻辑，直接获取录屏服务器实例
  Optional<RegisteredServer> screenShareServer = proxy.getServer("录屏服务器的名称");
  if (screenShareServer.isPresent()) {
      // 检查服务器是否有在线玩家（Velocity要求必须有玩家才能发消息）
      if (!screenShareServer.get().getPlayersConnected().isEmpty()) {
          // 取该服务器上的任意一个玩家连接
          screenShareServer.get().getPlayersConnected().stream().findAny().ifPresent(player -> {
              player.getCurrentServer().ifPresent(connection -> {
                  connection.sendPluginMessage(IDENTIFIER, out.toByteArray());
                  logger.info("Message sent to screen share server, staffer name: " + stafferName + " (role: " + stafferRole + ") and suspect: " + suspectName + " (role: " + suspectRole + ")");
              });
          });
      } else {
          logger.warn("No players on screen share server, cannot send plugin message.");
      }
  } else {
      logger.warn("Screen share server not found in proxy config.");
  }
  

• 移除Spigot端不必要的延迟：onPluginMessageReceived本身在主线程执行，无需额外延迟，直接处理消息：

  @Override
  public void onPluginMessageReceived(String channel, Player player, byte[] message) {
      if (!channel.equals("test:screenshare")) {
          getLogger().info("Wrong channel: " + channel);
          return;
      }
  
      ByteArrayDataInput in = ByteStreams.newDataInput(message);
      String subchannel = in.readUTF();
  
      if (subchannel.equals("RoleUpdate")) {
          String stafferRole = in.readUTF();
          String stafferName = in.readUTF();
          String suspectRole = in.readUTF();
          String suspectName = in.readUTF();
  
          getLogger().info("Received roles: " + stafferRole + " for " + stafferName + " and " + suspectRole + " for " + suspectName);
      } else {
          getLogger().info("Subchannel not found: " + subchannel);
      }
  }
  

• 确认频道注册一致性：在Spigot插件的plugin.yml中显式声明频道，确保服务器加载时正确注册：

  plugin:
    channels:
      - test:screenshare
  

• 添加注册日志验证：在Spigot端onEnable中添加日志，确认频道注册成功：

  @Override
  public void onEnable() {
      getServer().getMessenger().registerOutgoingPluginChannel(this, "test:screenshare");
      getServer().getMessenger().registerIncomingPluginChannel(this, "test:screenshare", this);
      getLogger().info("Registered plugin channel: test:screenshare");
      // ...其他代码
  }
  

内容的提问来源于stack exchange，提问作者Giuseppe Gentile