Netty 4中如何处理PING/PONG帧？

Question

class ClientWebSocketHandler extends SimpleChannelInboundHandler<WebSocketFrame> {

  @Override
    protected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame frame) throws Exception {

    }
}

我只能收到TextWebSocketFrame

如何处理PingWebSocketFrame和PongWebSocketFrame，我想知道客户端何时发送Ping/Pong




Answer 1

在任何WebSocketFrame到达您的SimpleChannelInboundHandler之前，Netty已收到PingWebSocketFrame和PongWebSocketFrame。有关其处理逻辑，请参见抽象WebSocketProtocolHandler。

Answer 2

这样：（知道channelRead0已弃用，应该在5.0版本后删除或不支持，请在评论中询问您是否想要最新的答案）

/**
 * * <strong>Please keep in mind that this method will be renamed to
 * {@code messageReceived(ChannelHandlerContext, I)} in 5.0.</strong>
 */
@Override
public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
    Channel ch = ctx.channel();
    if (!handshaker.isHandshakeComplete()) {
        handshaker.finishHandshake(ch, (FullHttpResponse) msg);
        l.error("WebSocket Client connected!");
        handshakeFuture.setSuccess();
        return;
    }

    if (msg instanceof FullHttpResponse) {
        FullHttpResponse response = (FullHttpResponse) msg;
        throw new IllegalStateException("Unexpected FullHttpResponse (getStatus=" + response.status() + ", content="
            + response.content().toString(CharsetUtil.UTF_8) + ')');
    }


    WebSocketFrame frame = (WebSocketFrame) msg;
    if (frame instanceof TextWebSocketFrame) {
        TextWebSocketFrame textFrame = (TextWebSocketFrame) frame;
        l.info("WebSocket Client received message:{} ", textFrame.text());

        //needed if the server close the socket if no ping send for long
        //better to send the ping with a timer
        // it allwos to choose the rate
        ch.write(new PingWebSocketFrame());

    } else if (frame instanceof PongWebSocketFrame) {
        l.info("WebSocket Client received pong");
    } else if (frame instanceof CloseWebSocketFrame) {
        l.info("WebSocket Client received closing");
        ch.close();
    }
}