public void OnMqttMsgSubscribeReceived(MqttClientConnection clientConnection, ushort messageId, string[] topics, byte[] qosLevels)
{
var wasSubscribed = false;
for (var i = 0; i < topics.Length; i++)
{
if (uacManager.AuthenticateSubscriber(clientConnection, topics[i]))
{
// TODO : business logic to grant QoS levels based on some conditions ?
// now the broker granted the QoS levels requested by client
// subscribe client for each topic and QoS level requested
MqttSubscriberManager.Subscribe(topics[i], qosLevels[i], clientConnection);
wasSubscribed = true;
}
}
if (wasSubscribed)
{
// send SUBACK message to the client
MqttOutgoingMessageManager.Suback(clientConnection, messageId, qosLevels);
foreach (var topic in topics)
{
// publish retained message on the current subscription
RetainedMessageManager.PublishRetaind(topic, clientConnection);
}
}
}
private void PublishThread()
{
while (this.isRunning)
{
try
{
var publish = (MqttMsgPublish)this.publishQueue.Take();
if (publish != null)
{
Interlocked.Increment(ref numberOfMessagesPublished);
// get all subscriptions for a topic
var subscriptions = MqttSubscriberManager.GetSubscriptionsByTopic(publish.Topic);
foreach (var subscription in subscriptions)
{
var qosLevel = (subscription.QosLevel < publish.QosLevel) ? subscription.QosLevel : publish.QosLevel;
// send PUBLISH message to the current subscriber
MqttMessageToClientConnectionManager.Publish(subscription.ClientConnection, publish.Topic, publish.Message, qosLevel, publish.Retain);
}
}
}
catch (Exception exception)
{
logger.LogException(this, exception);
}
}
}
/// <summary>
/// Publish retained message for a topic to a client
/// </summary>
/// <param name="topic">Topic to search for a retained message</param>
/// <param name="clientId">Client Id to send retained message</param>
public static void PublishRetaind(string topic, MqttClientConnection clientConnection)
{
MqttSubscription subscription = MqttSubscriberManager.GetSubscription(topic, clientConnection);
// add subscription to list of subscribers for receiving retained messages
if (subscription != null)
{
SubscribersForRetained.Add(subscription);
}
}
public void OnConnectionClosed(MqttClientConnection clientConnection)
{
// if client is connected
MqttClientConnection connectedClient;
if (clientConnection.IsConnected && MqttBroker.TryRemoveClientConnection(clientConnection.ClientId, out connectedClient))
{
// client has a will message
if (clientConnection.WillFlag)
{
// create the will PUBLISH message
MqttMsgPublish publish = new MqttMsgPublish(clientConnection.WillTopic, Encoding.UTF8.GetBytes(clientConnection.WillMessage), false, clientConnection.WillQosLevel, false);
// publish message through publisher manager
this.publishManager.Publish(publish);
}
// if not clean session
if (!clientConnection.CleanSession)
{
List <MqttSubscription> subscriptions = clientConnection.Subscriptions.Values.ToList();
if (subscriptions.Count > 0)
{
MqttSessionManager.SaveSession(clientConnection.ClientId, clientConnection.Session, subscriptions);
// TODO : persist client session if broker close
}
}
foreach (var topic in clientConnection.Subscriptions.Keys)
{
// delete client from runtime subscription
MqttSubscriberManager.Unsubscribe(topic, clientConnection);
}
// close the client
CloseClientConnection(clientConnection);
clientConnectionManager.ReturnConnection(clientConnection);
Interlocked.Decrement(ref numberOfConnectedClients);
}
}
public void OnMqttMsgConnected(MqttClientConnection clientConnection, MqttMsgConnect message)
{
clientConnection.ProtocolVersion = (MqttProtocolVersion)message.ProtocolVersion;
// verify message to determine CONNACK message return code to the client
byte returnCode = MqttConnectVerify(message);
// [v3.1.1] if client id is zero length, the broker assigns a unique identifier to it
var clientId = (message.ClientId.Length != 0) ? message.ClientId : Guid.NewGuid().ToString();
// connection "could" be accepted
if (returnCode == MqttMsgConnack.CONN_ACCEPTED)
{
// check if there is a client already connected with same client Id
MqttClientConnection clientConnectionConnected = MqttBroker.GetClientConnection(clientId);
// force connection close to the existing client (MQTT protocol)
if (clientConnectionConnected != null)
{
OnConnectionClosed(clientConnectionConnected);
}
// add client to the collection
MqttBroker.TryAddClientConnection(clientId, clientConnection);
Interlocked.Increment(ref numberOfConnectedClients);
}
// connection accepted, load (if exists) client session
if (returnCode == MqttMsgConnack.CONN_ACCEPTED)
{
// check if not clean session and try to recovery a session
if (!message.CleanSession)
{
// create session for the client
MqttClientSession clientSession = new MqttClientSession(clientId);
// get session for the connected client
MqttBrokerSession session = MqttSessionManager.GetSession(clientId);
// [v3.1.1] session present flag
bool sessionPresent = false;
// set inflight queue into the client session
if (session != null)
{
clientSession.InflightMessages = session.InflightMessages;
// [v3.1.1] session present flag
if (clientConnection.ProtocolVersion == MqttProtocolVersion.Version_3_1_1)
{
sessionPresent = true;
}
}
// send CONNACK message to the client
MqttOutgoingMessageManager.Connack(clientConnection, message, returnCode, clientId, sessionPresent);
// load/inject session to the client
clientConnection.LoadSession(clientSession);
if (session != null)
{
// set reference to connected client into the session
session.ClientConnection = clientConnection;
// there are saved subscriptions
if (session.Subscriptions != null)
{
// register all subscriptions for the connected client
foreach (MqttSubscription subscription in session.Subscriptions)
{
MqttSubscriberManager.Subscribe(
subscription.Topic,
subscription.QosLevel,
clientConnection);
// publish retained message on the current subscription
RetainedMessageManager.PublishRetaind(subscription.Topic, clientConnection);
}
}
// there are saved outgoing messages
if (session.OutgoingMessages.Count > 0)
{
// publish outgoing messages for the session
this.publishManager.PublishSession(session.ClientId);
}
}
}
// requested clean session
else
{
// send CONNACK message to the client
MqttOutgoingMessageManager.Connack(clientConnection, message, returnCode, clientId, false);
MqttSessionManager.ClearSession(clientId);
}
}
else
{
// send CONNACK message to the client
MqttOutgoingMessageManager.Connack(clientConnection, message, returnCode, clientId, false);
}
}