channelRead() — netty Function Reference

Architecture documentation for the channelRead() function in MqttHeartBeatBrokerHandler.java from the netty codebase.

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Entity Profile

Buffer→ Telemetry→ channelRead() — netty Function Reference

Dependency Diagram

graph TD
  95c3acb0_49ad_0c82_8d23_9ac5ee200095["channelRead()"]
  fef21bb2_cd7b_3e63_44fc_7bd83af8b9b8["MqttHeartBeatBrokerHandler"]
  95c3acb0_49ad_0c82_8d23_9ac5ee200095 -->|defined in| fef21bb2_cd7b_3e63_44fc_7bd83af8b9b8
  style 95c3acb0_49ad_0c82_8d23_9ac5ee200095 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

example/src/main/java/io/netty/example/mqtt/heartBeat/MqttHeartBeatBrokerHandler.java lines 40–67

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        MqttMessage mqttMessage = (MqttMessage) msg;
        System.out.println("Received MQTT message: " + mqttMessage);
        switch (mqttMessage.fixedHeader().messageType()) {
        case CONNECT:
            MqttFixedHeader connackFixedHeader =
                    new MqttFixedHeader(MqttMessageType.CONNACK, false, MqttQoS.AT_MOST_ONCE, false, 0);
            MqttConnAckVariableHeader mqttConnAckVariableHeader =
                    new MqttConnAckVariableHeader(MqttConnectReturnCode.CONNECTION_ACCEPTED, false);
            MqttConnAckMessage connack = new MqttConnAckMessage(connackFixedHeader, mqttConnAckVariableHeader);
            ctx.writeAndFlush(connack);
            break;
        case PINGREQ:
            MqttFixedHeader pingreqFixedHeader = new MqttFixedHeader(MqttMessageType.PINGRESP, false,
                                                                     MqttQoS.AT_MOST_ONCE, false, 0);
            MqttMessage pingResp = new MqttMessage(pingreqFixedHeader);
            ctx.writeAndFlush(pingResp);
            break;
        case DISCONNECT:
            ctx.close();
            break;
        default:
            System.out.println("Unexpected message type: " + mqttMessage.fixedHeader().messageType());
            ReferenceCountUtil.release(msg);
            ctx.close();
        }
    }