Exposed method to retrieve the list of Server's connected clients (issue #448)

broker/src/main/java/io/moquette/broker/ClientDescriptor.java

@@ -0,0 +1,52 @@
+package io.moquette.broker;
+
+import java.util.Objects;
+
+public class ClientDescriptor {
+
+    private final String clientID;
+    private final String address;
+    private final int port;
+
+    ClientDescriptor(String clientID, String address, int port) {
+        this.clientID = clientID;
+        this.address = address;
+        this.port = port;
+    }
+
+    public String getClientID() {
+        return clientID;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ClientDescriptor that = (ClientDescriptor) o;
+        return port == that.port &&
+            Objects.equals(clientID, that.clientID) &&
+            Objects.equals(address, that.address);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(clientID, address, port);
+    }
+
+    @Override
+    public String toString() {
+        return "ClientDescriptor{" +
+            "clientID='" + clientID + '\'' +
+            ", address='" + address + '\'' +
+            ", port=" + port +
+            '}';
+    }
+}

broker/src/main/java/io/moquette/broker/MQTTConnection.java

@@ -25,6 +25,7 @@ import io.netty.handler.timeout.IdleStateHandler;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.net.InetSocketAddress;
 import java.nio.charset.StandardCharsets;
 import java.util.*;
 import java.util.concurrent.TimeUnit;
@@ -488,4 +489,8 @@ final class MQTTConnection {
     public String toString() {
         return "MQTTConnection{channel=" + channel + ", connected=" + connected + '}';
     }
+
+    InetSocketAddress remoteAddress() {
+        return (InetSocketAddress) channel.remoteAddress();
+    }
 }

broker/src/main/java/io/moquette/broker/MQTTConnectionFactory.java

@@ -33,7 +33,7 @@ class MQTTConnectionFactory {
         this.postOffice = postOffice;
     }
 
-    public MQTTConnection create(Channel channel) {
+    MQTTConnection create(Channel channel) {
         return new MQTTConnection(channel, brokerConfig, authenticator, sessionRegistry, postOffice);
     }
 }

broker/src/main/java/io/moquette/broker/Server.java

@@ -34,10 +34,7 @@ import java.io.File;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.text.ParseException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.Properties;
+import java.util.*;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 
@@ -53,6 +50,7 @@ public class Server {
     private PostOffice dispatcher;
     private BrokerInterceptor interceptor;
     private H2Builder h2Builder;
+    private SessionRegistry sessions;
 
     public static void main(String[] args) throws IOException {
         final Server server = new Server();
@@ -136,7 +134,7 @@ public class Server {
     }
 
     public void startServer(IConfig config, List<? extends InterceptHandler> handlers, ISslContextCreator sslCtxCreator,
-                            IAuthenticator authenticator, IAuthorizatorPolicy authorizatorPolicy) throws IOException {
+                            IAuthenticator authenticator, IAuthorizatorPolicy authorizatorPolicy) {
         final long start = System.currentTimeMillis();
         if (handlers == null) {
             handlers = Collections.emptyList();
@@ -179,7 +177,7 @@ public class Server {
         ISubscriptionsDirectory subscriptions = new CTrieSubscriptionDirectory();
         subscriptions.init(subscriptionsRepository);
         final Authorizator authorizator = new Authorizator(authorizatorPolicy);
-        SessionRegistry sessions = new SessionRegistry(subscriptions, queueRepository, authorizator);
+        sessions = new SessionRegistry(subscriptions, queueRepository, authorizator);
         dispatcher = new PostOffice(subscriptions, retainedRepository, sessions, interceptor, authorizator);
         final BrokerConfiguration brokerConfig = new BrokerConfiguration(config);
         MQTTConnectionFactory connectionFactory = new MQTTConnectionFactory(brokerConfig, authenticator, sessions,
@@ -195,11 +193,6 @@ public class Server {
     }
 
     private IAuthorizatorPolicy initializeAuthorizatorPolicy(IAuthorizatorPolicy authorizatorPolicy, IConfig props) {
-//        if (authorizatorPolicy == null) {
-//            authorizatorPolicy = new PermitAllAuthorizatorPolicy();
-//        }
-//        return authorizatorPolicy;
-
         LOG.debug("Configuring MQTT authorizator policy");
         String authorizatorClassName = props.getProperty(BrokerConstants.AUTHORIZATOR_CLASS_NAME, "");
         if (authorizatorPolicy == null && !authorizatorClassName.isEmpty()) {
@@ -215,7 +208,7 @@ public class Server {
                     IResourceLoader resourceLoader = props.getResourceLoader();
                     authorizatorPolicy = ACLFileParser.parse(resourceLoader.loadResource(aclFilePath));
                 } catch (ParseException pex) {
-                    LOG.error("Unable to parse ACL file. path=" + aclFilePath, pex);
+                    LOG.error("Unable to parse ACL file. path = {}", aclFilePath, pex);
                 }
             } else {
                 authorizatorPolicy = new PermitAllAuthorizatorPolicy();
@@ -226,11 +219,6 @@ public class Server {
     }
 
     private IAuthenticator initializeAuthenticator(IAuthenticator authenticator, IConfig props) {
-//        if (authenticator == null) {
-//            authenticator = new AcceptAllAuthenticator();
-//        }
-//        return authenticator;
-
         LOG.debug("Configuring MQTT authenticator");
         String authenticatorClassName = props.getProperty(BrokerConstants.AUTHENTICATOR_CLASS_NAME, "");
 
@@ -391,4 +379,11 @@ public class Server {
         LOG.info("Removing MQTT message interceptor. InterceptorId={}", interceptHandler.getID());
         interceptor.removeInterceptHandler(interceptHandler);
     }
+
+    /**
+     * Return a list of descriptors of connected clients.
+     * */
+    public Collection<ClientDescriptor> listConnectedClients() {
+        return sessions.listConnectedClients();
+    }
 }

broker/src/main/java/io/moquette/broker/Session.java

@@ -23,6 +23,7 @@ import io.netty.util.ReferenceCountUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.net.InetSocketAddress;
 import java.util.*;
 import java.util.concurrent.DelayQueue;
 import java.util.concurrent.Delayed;
@@ -368,6 +369,13 @@ class Session {
         ReferenceCountUtil.release(removedMsg);
     }
 
+    Optional<InetSocketAddress> remoteAddress() {
+        if (connected()) {
+            return Optional.of(mqttConnection.remoteAddress());
+        }
+        return Optional.empty();
+    }
+
     @Override
     public String toString() {
         return "Session{" +

broker/src/main/java/io/moquette/broker/SessionRegistry.java

@@ -26,9 +26,13 @@ import io.netty.handler.codec.mqtt.MqttQoS;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.net.InetSocketAddress;
+import java.util.Collection;
+import java.util.Optional;
 import java.util.Queue;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.stream.Collectors;
 
 public class SessionRegistry {
 
@@ -245,4 +249,19 @@ public class SessionRegistry {
     private void dropQueuesForClient(String clientId) {
         queues.remove(clientId);
     }
+
+    Collection<ClientDescriptor> listConnectedClients() {
+        return pool.values().stream()
+            .filter(Session::connected)
+            .map(this::createClientDescriptor)
+            .filter(Optional::isPresent)
+            .map(Optional::get)
+            .collect(Collectors.toList());
+    }
+
+    private Optional<ClientDescriptor> createClientDescriptor(Session s) {
+        final String clientID = s.getClientID();
+        final Optional<InetSocketAddress> remoteAddressOpt = s.remoteAddress();
+        return remoteAddressOpt.map(r -> new ClientDescriptor(clientID, r.getHostString(), r.getPort()));
+    }
 }