Netty IdleStateHandler 的问题 - 我测试它的方式错误吗?

2022-01-19 00:00:00 network-programming java netty jboss heartbeat

我有一个玩具 Netty 服务器，当他们的频道上没有发生任何事情时，我正在尝试向客户端发送心跳消息.我正在通过远程登录到服务器，写一条消息然后不发送任何东西来测试这个，但是我没有听到心跳！

I have a toy Netty server and am trying to send heartbeat messages to clients when nothing has happened on their channels. I am testing this by telnetting to the server, writing a message and then not sending anything, but I get no hearbeat!

控制台:

>>telnet localhost 6969
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
>>foo
Did you say 'foo'?

MyPipelineFactory.java

MyPipelineFactory.java

public class MyPipelineFactory implements ChannelPipelineFactory {
    private final Timer timer;
    private static final ChannelHandler stringDecoder = new StringDecoder();
    private static final ChannelHandler stringEncoder = new StringEncoder();
    private final ChannelHandler idleStateHandler;

    public MyPipelineFactory(Timer t) {
        this.timer = t;
        this.idleStateHandler = new IdleStateHandler(timer, 5, 5, 5);
    }

    public ChannelPipeline getPipeline() {
        // create default pipeline from static method
        ChannelPipeline pipeline = Channels.pipeline();
        pipeline.addLast("idleStateHandler", this.idleStateHandler); // heartbeat
        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(1024, Delimiters.lineDelimiter()));
        //pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(1024,0,1)); // get header from message
        pipeline.addLast("stringDecoder", stringDecoder);
        pipeline.addLast("stringEncoder", stringEncoder);
        pipeline.addLast("ServerHandler", new ServerHandler()); // goes at the end

        return pipeline;
    }
}

HeartbeatHandler.java

HeartbeatHandler.java

public class HeartbeatHandler extends IdleStateAwareChannelHandler {

    @Override
    public void channelIdle(ChannelHandlerContext ctx, IdleStateEvent e) {
        if (e.getState() == IdleState.READER_IDLE) {
            System.out.println("Reader idle, closing channel");
            //e.getChannel().close();
            e.getChannel().write("heartbeat-reader_idle");
        }
        else if (e.getState() == IdleState.WRITER_IDLE) {
            System.out.println("Writer idle, sending heartbeat");
            e.getChannel().write("heartbeat-writer_idle");
        }
        else if (e.getState() == IdleState.ALL_IDLE) {
            System.out.println("All idle, sending heartbeat");
            e.getChannel().write("heartbeat-all_idle");
        }
    }
}

<小时>

固定:

我忘记了 HeartbeatHandler，它需要 IdleStateHandler(这部分对我来说并不明显).这行得通.

I forgot to have the HeartbeatHandler, which requires the IdleStateHandler (this part wasn't obvious to me). That works.

public class MyPipelineFactory implements ChannelPipelineFactory {
    private final Timer timer;
    private static final ChannelHandler stringDecoder = new StringDecoder();
    private static final ChannelHandler stringEncoder = new StringEncoder();
    private final ChannelHandler idleStateHandler;
    private final ChannelHandler heartbeatHandler;

    public MyPipelineFactory(Timer t) {
        this.timer = t;
        this.idleStateHandler = new IdleStateHandler(timer, 5, 5, 5);
        this.heartbeatHandler = new HeartbeatHandler();
    }

    public ChannelPipeline getPipeline() {
        // create default pipeline from static method
        ChannelPipeline pipeline = Channels.pipeline();
        pipeline.addLast("idleStateHandler", this.idleStateHandler);
        pipeline.addLast("heartbeatHandler", this.heartbeatHandler); // heartbeat
        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(1024, Delimiters.lineDelimiter()));
        //pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(1024,0,1)); // get header from message
        pipeline.addLast("stringDecoder", stringDecoder);
        pipeline.addLast("stringEncoder", stringEncoder);
        pipeline.addLast("ServerHandler", new ServerHandler()); // goes at the end

        return pipeline;
    }
}

推荐答案

您错过了在 ChannelPipeline 中添加 HeartbeatHandler.您需要将 IdleStateHandler AND HeartbeatHandler 添加到 ChannelPipeline 以使其工作.

You missed to add the HeartbeatHandler in the ChannelPipeline. You need to add IdleStateHandler AND HeartbeatHandler to the ChannelPipeline to have it work.

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