shenyu-protocol/shenyu-protocol-mqtt/src/main/java/org/apache/shenyu/protocol/mqtt/Unsubscribe.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.shenyu.protocol.mqtt;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.mqtt.MqttFixedHeader;
import io.netty.handler.codec.mqtt.MqttMessageType;
import io.netty.handler.codec.mqtt.MqttQoS;
import io.netty.handler.codec.mqtt.MqttUnsubscribeMessage;
import io.netty.handler.codec.mqtt.MqttUnsubAckMessage;
import org.apache.shenyu.common.utils.Singleton;
import org.apache.shenyu.protocol.mqtt.repositories.SubscribeRepository;

import java.util.List;

import static io.netty.handler.codec.mqtt.MqttMessageIdVariableHeader.from;

/**
 * Unsubscribe from named topics.
 */
public class Unsubscribe extends MessageType {

    @Override
    public void unsubscribe(final ChannelHandlerContext ctx, final MqttUnsubscribeMessage msg) {
        if (isConnected()) {
            return;
        }
        List<String> topics = msg.payload().topics();
        Channel channel = ctx.channel();
        Singleton.INST.get(SubscribeRepository.class).remove(topics, channel);
        int packetId = msg.variableHeader().messageId();
        MqttFixedHeader mqttFixedHeader = new MqttFixedHeader(MqttMessageType.UNSUBACK, false, MqttQoS.AT_MOST_ONCE, false, 0);
        MqttUnsubAckMessage mqttUnsubAckMessage = new MqttUnsubAckMessage(mqttFixedHeader, from(packetId));
        channel.writeAndFlush(mqttUnsubAckMessage);
    }

}