Extract base MQTT decoder

1 files changed, 96 insertions, 0 deletions

diff --git a/src/main/java/org/traccar/BaseMqttProtocolDecoder.java b/src/main/java/org/traccar/BaseMqttProtocolDecoder.java
new file mode 100644
index 000000000..0388563f5
--- /dev/null
+++ b/src/main/java/org/traccar/BaseMqttProtocolDecoder.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright 2023 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed 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.traccar;
+
+import io.netty.channel.Channel;
+import io.netty.handler.codec.mqtt.MqttConnectMessage;
+import io.netty.handler.codec.mqtt.MqttConnectReturnCode;
+import io.netty.handler.codec.mqtt.MqttMessage;
+import io.netty.handler.codec.mqtt.MqttMessageBuilders;
+import io.netty.handler.codec.mqtt.MqttPublishMessage;
+import io.netty.handler.codec.mqtt.MqttSubscribeMessage;
+import org.traccar.session.DeviceSession;
+
+import java.net.SocketAddress;
+
+public abstract class BaseMqttProtocolDecoder extends BaseProtocolDecoder {
+
+    public BaseMqttProtocolDecoder(Protocol protocol) {
+        super(protocol);
+    }
+
+    protected abstract Object decode(DeviceSession deviceSession, MqttPublishMessage message) throws Exception;
+
+    @Override
+    protected final Object decode(
+            Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {
+
+        if (msg instanceof MqttConnectMessage) {
+
+            MqttConnectMessage message = (MqttConnectMessage) msg;
+
+            DeviceSession deviceSession = getDeviceSession(
+                    channel, remoteAddress, message.payload().clientIdentifier());
+
+            MqttConnectReturnCode returnCode = deviceSession != null
+                    ? MqttConnectReturnCode.CONNECTION_ACCEPTED
+                    : MqttConnectReturnCode.CONNECTION_REFUSED_IDENTIFIER_REJECTED;
+
+            MqttMessage response = MqttMessageBuilders.connAck().returnCode(returnCode).build();
+
+            if (channel != null) {
+                channel.writeAndFlush(new NetworkMessage(response, remoteAddress));
+            }
+
+        } else if (msg instanceof MqttSubscribeMessage) {
+
+            MqttSubscribeMessage message = (MqttSubscribeMessage) msg;
+
+            MqttMessage response = MqttMessageBuilders.subAck()
+                    .packetId(message.variableHeader().messageId())
+                    .build();
+
+            if (channel != null) {
+                channel.writeAndFlush(new NetworkMessage(response, remoteAddress));
+            }
+
+        } else if (msg instanceof MqttPublishMessage) {
+
+            DeviceSession deviceSession = getDeviceSession(channel, remoteAddress);
+            if (deviceSession == null) {
+                return null;
+            }
+
+            MqttPublishMessage message = (MqttPublishMessage) msg;
+
+            Object result = decode(deviceSession, message);
+
+            MqttMessage response = MqttMessageBuilders.pubAck()
+                    .packetId(message.variableHeader().packetId())
+                    .build();
+
+            if (channel != null) {
+                channel.writeAndFlush(new NetworkMessage(response, remoteAddress));
+            }
+
+            return result;
+
+        }
+
+        return null;
+    }
+
+}