Server.java

/*
 * Copyright 2016 Red Hat Inc.
 *
 * 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 io.vertx.example.mqtt.app;

import io.netty.handler.codec.mqtt.MqttQoS;
import io.vertx.core.AbstractVerticle;
import io.vertx.core.buffer.Buffer;
import io.vertx.example.mqtt.util.Runner;
import io.vertx.mqtt.MqttServer;
import io.vertx.mqtt.MqttTopicSubscription;

import java.util.ArrayList;
import java.util.List;

/**
 * An example of using the MQTT server
 */
public class Server extends AbstractVerticle {

  // Convenience method so you can run it in your IDE
  public static void main(String[] args) {
    Runner.runExample(Server.class);
  }

  @Override
  public void start() throws Exception {

    MqttServer mqttServer = MqttServer.create(vertx);

    mqttServer
      .endpointHandler(endpoint -> {

        // shows main connect info
        System.out.println("MQTT client [" + endpoint.clientIdentifier() + "] request to connect, clean session = " + endpoint.isCleanSession());

        if (endpoint.auth() != null) {
          System.out.println("[username = " + endpoint.auth().getUsername() + ", password = " + endpoint.auth().getPassword() + "]");
        }
        if (endpoint.will() != null) {
          System.out.println("[will flag = " + endpoint.will().isWillFlag() + " topic = " + endpoint.will().getWillTopic() + " msg = " + endpoint.will().getWillMessage() +
            " QoS = " + endpoint.will().getWillQos() + " isRetain = " + endpoint.will().isWillRetain() + "]");
        }

        System.out.println("[keep alive timeout = " + endpoint.keepAliveTimeSeconds() + "]");

        // accept connection from the remote client
        endpoint.accept(false);

        // handling requests for subscriptions
        endpoint.subscribeHandler(subscribe -> {

          List<MqttQoS> grantedQosLevels = new ArrayList<>();
          for (MqttTopicSubscription s : subscribe.topicSubscriptions()) {
            System.out.println("Subscription for " + s.topicName() + " with QoS " + s.qualityOfService());
            grantedQosLevels.add(s.qualityOfService());
          }
          // ack the subscriptions request
          endpoint.subscribeAcknowledge(subscribe.messageId(), grantedQosLevels);

          // just as example, publish a message on the first topic with requested QoS
          endpoint.publish(subscribe.topicSubscriptions().get(0).topicName(),
            Buffer.buffer("Hello from the Vert.x MQTT server"),
            subscribe.topicSubscriptions().get(0).qualityOfService(),
            false,
            false);

          // specifing handlers for handling QoS 1 and 2
          endpoint.publishAcknowledgeHandler(messageId -> {

            System.out.println("Received ack for message = " + messageId);

          }).publishReceivedHandler(messageId -> {

            endpoint.publishRelease(messageId);

          }).publishCompletionHandler(messageId -> {

            System.out.println("Received ack for message = " + messageId);
          });
        });

        // handling requests for unsubscriptions
        endpoint.unsubscribeHandler(unsubscribe -> {

          for (String t : unsubscribe.topics()) {
            System.out.println("Unsubscription for " + t);
          }
          // ack the subscriptions request
          endpoint.unsubscribeAcknowledge(unsubscribe.messageId());
        });

        // handling ping from client
        endpoint.pingHandler(v -> {

          System.out.println("Ping received from client");
        });

        // handling disconnect message
        endpoint.disconnectHandler(v -> {

          System.out.println("Received disconnect from client");
        });

        // handling closing connection
        endpoint.closeHandler(v -> {

          System.out.println("Connection closed");
        });

        // handling incoming published messages
        endpoint.publishHandler(message -> {

          System.out.println("Just received message on [" + message.topicName() + "] payload [" + message.payload() + "] with QoS [" + message.qosLevel() + "]");

          if (message.qosLevel() == MqttQoS.AT_LEAST_ONCE) {
            endpoint.publishAcknowledge(message.messageId());
          } else if (message.qosLevel() == MqttQoS.EXACTLY_ONCE) {
            endpoint.publishReceived(message.messageId());
          }

        }).publishReleaseHandler(messageId -> {
          endpoint.publishComplete(messageId);
        });
      })
      .listen(1883, "0.0.0.0", ar -> {

        if (ar.succeeded()) {
          System.out.println("MQTT server is listening on port " + mqttServer.actualPort());
        } else {
          System.err.println("Error on starting the server" + ar.cause().getMessage());
        }
      });
  }
}