fix: set MQTT sessionPresent from cleanSession flag and stored session state (#6889)

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

@@ -26,9 +26,14 @@
 import org.apache.commons.lang3.StringUtils;
 import org.apache.shenyu.common.utils.Singleton;
 import org.apache.shenyu.protocol.mqtt.repositories.ChannelRepository;
+import org.apache.shenyu.protocol.mqtt.repositories.MqttSession;
+import org.apache.shenyu.protocol.mqtt.repositories.SessionRepository;
+import org.apache.shenyu.protocol.mqtt.repositories.SubscribeRepository;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.Objects;
+
 import static io.netty.channel.ChannelFutureListener.CLOSE_ON_FAILURE;
 import static io.netty.handler.codec.mqtt.MqttConnectReturnCode.CONNECTION_REFUSED_BAD_USER_NAME_OR_PASSWORD;
 import static io.netty.handler.codec.mqtt.MqttConnectReturnCode.CONNECTION_REFUSED_IDENTIFIER_REJECTED;
@@ -74,9 +79,30 @@ public void connect(final ChannelHandlerContext ctx, final MqttConnectMessage ms
 
         // record connect
         Singleton.INST.get(ChannelRepository.class).add(ctx.channel(), clientId);
+
+        boolean cleanSession = msg.variableHeader().isCleanSession();
+        SessionRepository sessionRepository = Singleton.INST.get(SessionRepository.class);
+        MqttSession session = sessionRepository.get(clientId);
+        // MQTT-3.2.2-6/7: session present is only true when the client connects
+        // with cleanSession=0 and the server holds a stored session for the clientId.
+        boolean sessionPresent = !cleanSession && Objects.nonNull(session);
+        if (cleanSession) {
+            // A clean-session connect must discard any previously stored session.
+            session = new MqttSession(clientId, true);
+            sessionRepository.add(clientId, session);
+        } else if (Objects.isNull(session)) {
+            session = new MqttSession(clientId, false);
+            sessionRepository.add(clientId, session);
+        }
+        if (sessionPresent && !session.getTopics().isEmpty()) {
+            // Resume the stored subscriptions (with their QoS) for the new channel.
+            Singleton.INST.get(SubscribeRepository.class)
+                    .add(ctx.channel(), session.getTopicSubscriptions());
+        }
+
         MqttConnAckMessage ackMessage = MqttMessageBuilders.connAck()
                 .returnCode(MqttConnectReturnCode.CONNECTION_ACCEPTED)
-                .sessionPresent(true)
+                .sessionPresent(sessionPresent)
                 .build();
         ctx.writeAndFlush(ackMessage);
         setConnected(ctx.channel(), true);

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

@@ -21,6 +21,11 @@
 import io.netty.channel.ChannelHandlerContext;
 import org.apache.shenyu.common.utils.Singleton;
 import org.apache.shenyu.protocol.mqtt.repositories.ChannelRepository;
+import org.apache.shenyu.protocol.mqtt.repositories.MqttSession;
+import org.apache.shenyu.protocol.mqtt.repositories.SessionRepository;
+import org.apache.shenyu.protocol.mqtt.repositories.SubscribeRepository;
+
+import java.util.Objects;
 
 /**
  * The DISCONNECT message is sent from the client to the server to indicate
@@ -37,7 +42,15 @@ public class Disconnect extends MessageType {
     @Override
     public void disconnect(final ChannelHandlerContext ctx) {
         //// todo Last words
-        //// todo Clean session
+        String clientId = Singleton.INST.get(ChannelRepository.class).get(ctx.channel());
+        if (Objects.nonNull(clientId)) {
+            MqttSession session = Singleton.INST.get(SessionRepository.class).get(clientId);
+            if (Objects.nonNull(session) && session.isCleanSession()) {
+                // A clean-session disconnect discards all stored session state.
+                Singleton.INST.get(SessionRepository.class).remove(clientId);
+            }
+        }
+        Singleton.INST.get(SubscribeRepository.class).removeChannel(ctx.channel());
         cleanChannel(ctx.channel());
         ctx.close();
     }

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

@@ -66,7 +66,10 @@ public void connect() {
                 messageType.pingReq(ctx);
                 break;
             case PUBACK:
+                break;
             case DISCONNECT:
+                messageType.disconnect(ctx);
+                break;
             default:
                 break;
         }

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

@@ -32,11 +32,15 @@
 import io.netty.util.CharsetUtil;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.shenyu.common.utils.Singleton;
+import org.apache.shenyu.protocol.mqtt.repositories.ChannelRepository;
+import org.apache.shenyu.protocol.mqtt.repositories.MqttSession;
+import org.apache.shenyu.protocol.mqtt.repositories.SessionRepository;
 import org.apache.shenyu.protocol.mqtt.repositories.SubscribeRepository;
 import org.apache.shenyu.protocol.mqtt.repositories.TopicRepository;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
 
 import static io.netty.channel.ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE;
@@ -69,6 +73,12 @@ public void subscribe(final ChannelHandlerContext ctx, final MqttSubscribeMessag
 
         Singleton.INST.get(SubscribeRepository.class).add(ctx.channel(), mqttTopicSubscriptions);
 
+        String clientId = Singleton.INST.get(ChannelRepository.class).get(ctx.channel());
+        MqttSession session = Singleton.INST.get(SessionRepository.class).get(clientId);
+        if (Objects.nonNull(session)) {
+            mqttTopicSubscriptions.forEach(subscription -> session.addTopic(subscription.topicName(), subscription.qualityOfService()));
+        }
+
         for (String ackTopic : ackTopics) {
             String message = Singleton.INST.get(TopicRepository.class).get(ackTopic);
             if (StringUtils.isNotEmpty(message)) {

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

@@ -25,9 +25,13 @@
 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.ChannelRepository;
+import org.apache.shenyu.protocol.mqtt.repositories.MqttSession;
+import org.apache.shenyu.protocol.mqtt.repositories.SessionRepository;
 import org.apache.shenyu.protocol.mqtt.repositories.SubscribeRepository;
 
 import java.util.List;
+import java.util.Objects;
 
 import static io.netty.channel.ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE;
 import static io.netty.handler.codec.mqtt.MqttMessageIdVariableHeader.from;
@@ -46,6 +50,11 @@ public void unsubscribe(final ChannelHandlerContext ctx, final MqttUnsubscribeMe
         List<String> topics = msg.payload().topics();
         Channel channel = ctx.channel();
         Singleton.INST.get(SubscribeRepository.class).remove(topics, channel);
+        String clientId = Singleton.INST.get(ChannelRepository.class).get(channel);
+        MqttSession session = Singleton.INST.get(SessionRepository.class).get(clientId);
+        if (Objects.nonNull(session)) {
+            topics.forEach(session::removeTopic);
+        }
         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));

shenyu-protocol/shenyu-protocol-mqtt/src/main/java/org/apache/shenyu/protocol/mqtt/repositories/MqttSession.java

@@ -0,0 +1,103 @@
+/*
+ * 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.repositories;
+
+import io.netty.handler.codec.mqtt.MqttQoS;
+import io.netty.handler.codec.mqtt.MqttTopicSubscription;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
+
+/**
+ * MQTT session state stored for a client.
+ */
+public class MqttSession {
+
+    private final String clientId;
+
+    private final boolean cleanSession;
+
+    private final Map<String, MqttQoS> topics = new ConcurrentHashMap<>();
+
+    /**
+     * MqttSession constructor.
+     * @param clientId clientId
+     * @param cleanSession cleanSession
+     */
+    public MqttSession(final String clientId, final boolean cleanSession) {
+        this.clientId = clientId;
+        this.cleanSession = cleanSession;
+    }
+
+    /**
+     * get clientId.
+     * @return clientId
+     */
+    public String getClientId() {
+        return clientId;
+    }
+
+    /**
+     * get cleanSession.
+     * @return cleanSession
+     */
+    public boolean isCleanSession() {
+        return cleanSession;
+    }
+
+    /**
+     * add topic with its QoS, replacing any existing subscription for the same topic.
+     * @param topic topic
+     * @param qos qos
+     * @return true if the topic was newly added
+     */
+    public boolean addTopic(final String topic, final MqttQoS qos) {
+        return Objects.isNull(topics.put(topic, qos));
+    }
+
+    /**
+     * remove topic.
+     * @param topic topic
+     * @return true if the topic was removed
+     */
+    public boolean removeTopic(final String topic) {
+        return Objects.nonNull(topics.remove(topic));
+    }
+
+    /**
+     * get topics.
+     * @return topics
+     */
+    public Set<String> getTopics() {
+        return topics.keySet();
+    }
+
+    /**
+     * get topic subscriptions with their QoS for session resume.
+     * @return topic subscriptions
+     */
+    public List<MqttTopicSubscription> getTopicSubscriptions() {
+        return topics.entrySet().stream()
+                .map(entry -> new MqttTopicSubscription(entry.getKey(), entry.getValue()))
+                .collect(Collectors.toList());
+    }
+}

shenyu-protocol/shenyu-protocol-mqtt/src/main/java/org/apache/shenyu/protocol/mqtt/repositories/SessionRepository.java

@@ -0,0 +1,45 @@
+/*
+ * 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.repositories;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Session repository, keyed by clientId.
+ */
+public class SessionRepository implements BaseRepository<String, MqttSession> {
+
+    private static final Map<String, MqttSession> SESSION_FACTORY = new ConcurrentHashMap<>();
+
+    @Override
+    public void add(final String clientId, final MqttSession session) {
+        SESSION_FACTORY.put(clientId, session);
+    }
+
+    @Override
+    public void remove(final String clientId) {
+        SESSION_FACTORY.remove(clientId);
+    }
+
+    @Override
+    public MqttSession get(final String clientId) {
+        return SESSION_FACTORY.get(clientId);
+    }
+
+}

shenyu-protocol/shenyu-protocol-mqtt/src/main/java/org/apache/shenyu/protocol/mqtt/repositories/SubscribeRepository.java

@@ -42,11 +42,8 @@ public class SubscribeRepository implements BaseRepository<List<String>, List<Ch
 
     @Override
     public void add(final List<String> topics, final List<Channel> channels) {
-        CompletableFuture.runAsync(() -> topics.parallelStream().forEach(s -> {
-            List<Channel> list = get(s);
-            list.addAll(channels);
-            TOPIC_CHANNEL_FACTORY.put(s, list);
-        }));
+        CompletableFuture.runAsync(() -> topics.parallelStream().forEach(s ->
+                TOPIC_CHANNEL_FACTORY.computeIfAbsent(s, key -> new CopyOnWriteArrayList<>()).addAll(channels)));
     }
 
     /**
@@ -55,11 +52,8 @@ public void add(final List<String> topics, final List<Channel> channels) {
      * @param mqttTopicSubscription mqtt subscription info
      */
     public void add(final Channel channel, final List<MqttTopicSubscription> mqttTopicSubscription) {
-        CompletableFuture.runAsync(() -> mqttTopicSubscription.parallelStream().forEach(s -> {
-            List<Channel> channels = get(s.topicName());
-            channels.add(channel);
-            TOPIC_CHANNEL_FACTORY.put(s.topicName(), channels);
-        }));
+        CompletableFuture.runAsync(() -> mqttTopicSubscription.parallelStream().forEach(s ->
+                TOPIC_CHANNEL_FACTORY.computeIfAbsent(s.topicName(), key -> new CopyOnWriteArrayList<>()).add(channel)));
     }
 
     @Override
@@ -81,6 +75,14 @@ public void remove(final List<String> topics, final Channel channel) {
         }));
     }
 
+    /**
+     * remove channel from all topics.
+     * @param channel channel
+     */
+    public void removeChannel(final Channel channel) {
+        CompletableFuture.runAsync(() -> TOPIC_CHANNEL_FACTORY.values().forEach(channels -> channels.remove(channel)));
+    }
+
     @Override
     public List<Channel> get(final List<String> topics) {
         Set<Channel> channels = new CopyOnWriteArraySet<>();