private void ClientsForSessionThread()
{
while (isRunning)
{
try
{
string clientId = this.clientsForSession.Take();
MqttBrokerSession session = MqttSessionManager.GetSession(clientId);
MqttMsgPublish outgoingMsg;
while (session.OutgoingMessages.TryDequeue(out outgoingMsg))
{
var query = from s in session.Subscriptions
where (new Regex(s.Topic)).IsMatch(outgoingMsg.Topic)
// check for topics based also on wildcard with regex
select s;
MqttSubscription subscription = query.FirstOrDefault();
if (subscription != null)
{
var qosLevel = (subscription.QosLevel < outgoingMsg.QosLevel) ? subscription.QosLevel : outgoingMsg.QosLevel;
MqttMessageToClientConnectionManager.Publish(subscription.ClientConnection, outgoingMsg.Topic, outgoingMsg.Message, qosLevel, outgoingMsg.Retain);
}
}
}
catch (Exception exception)
{
logger.LogException(this, exception);
}
}
}
/// <summary>
/// Save session for a client (all related subscriptions)
/// </summary>
/// <param name="clientId">Client Id to save subscriptions</param>
/// <param name="clientSession">Client session with inflight messages</param>
/// <param name="subscriptions">Subscriptions to save</param>
public void SaveSession(string clientId, MqttClientSession clientSession, List <MqttSubscription> subscriptions)
{
MqttBrokerSession session = null;
lock (this.sessions)
{
// session doesn't exist
if (!this.sessions.ContainsKey(clientId))
{
// create new session
session = new MqttBrokerSession();
session.ClientId = clientId;
// add to sessions list
this.sessions.Add(clientId, session);
}
else
{
// get existing session
session = this.sessions[clientId];
}
}
// null reference to disconnected client
session.Client = null;
// update subscriptions
session.Subscriptions = new List <MqttSubscription>();
lock (session.Subscriptions)
{
foreach (MqttSubscription subscription in subscriptions)
{
session.Subscriptions.Add(new MqttSubscription(subscription.ClientId, subscription.Topic, subscription.QosLevel, null));
}
}
// update inflight messages
session.InflightMessages = new Hashtable();
lock (session.InflightMessages)
{
foreach (MqttMsgContext msgContext in clientSession.InflightMessages.Values)
{
session.InflightMessages.Add(msgContext.Key, msgContext);
}
}
}
void Client_MqttMsgConnected(object sender, MqttMsgConnectEventArgs e)
{
// [v3.1.1] session present flag
bool sessionPresent = false;
// [v3.1.1] generated client id for client who provides client id zero bytes length
string clientId = null;
MqttClient client = (MqttClient)sender;
// verify message to determine CONNACK message return code to the client
byte returnCode = this.MqttConnectVerify(e.Message);
// [v3.1.1] if client id is zero length, the broker assigns a unique identifier to it
clientId = (e.Message.ClientId.Length != 0) ? e.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
MqttClient clientConnected = this.GetClient(clientId);
// force connection close to the existing client (MQTT protocol)
if (clientConnected != null)
{
this.CloseClient(clientConnected);
}
}
try
{
// connection accepted, load (if exists) client session
if (returnCode == MqttMsgConnack.CONN_ACCEPTED)
{
// check if not clean session and try to recovery a session
if (!e.Message.CleanSession)
{
// create session for the client
MqttClientSession clientSession = new MqttClientSession(clientId);
// get session for the connected client
MqttBrokerSession session = this.sessionManager.GetSession(clientId);
// set inflight queue into the client session
if (session != null)
{
clientSession.InflightMessages = session.InflightMessages;
// [v3.1.1] session present flag
if (client.ProtocolVersion == MqttProtocolVersion.Version_3_1_1)
{
sessionPresent = true;
}
}
// send CONNACK message to the client
client.Connack(e.Message, returnCode, clientId, sessionPresent);
// load/inject session to the client
client.LoadSession(clientSession);
if (session != null)
{
// set reference to connected client into the session
session.Client = client;
// there are saved subscriptions
if (session.Subscriptions != null)
{
// register all subscriptions for the connected client
foreach (MqttSubscription subscription in session.Subscriptions)
{
this.subscriberManager.Subscribe(subscription.Topic, subscription.QosLevel, client);
// publish retained message on the current subscription
this.publisherManager.PublishRetaind(subscription.Topic, clientId);
}
}
// there are saved outgoing messages
if (session.OutgoingMessages.Count > 0)
{
// publish outgoing messages for the session
this.publisherManager.PublishSession(session.ClientId);
}
}
//signal
EventHandler <MqttClientEventArgs> handler = DidAcceptNewClient;
if (handler != null)
{
MqttClientEventArgs arg = new MqttClientEventArgs();
arg.Client = client;
handler(this, arg);
}
}
// requested clean session
else
{
// send CONNACK message to the client
client.Connack(e.Message, returnCode, clientId, sessionPresent);
this.sessionManager.ClearSession(clientId);
}
}
else
{
// send CONNACK message to the client
client.Connack(e.Message, returnCode, clientId, sessionPresent);
}
}
catch (MqttCommunicationException)
{
this.CloseClient(client);
}
}
/// <summary>
/// Process the message queue to publish
/// </summary>
public void PublishThread()
{
int count;
byte qosLevel;
MqttMsgPublish publish;
// create event to signal that current thread is ended
this.publishEventEnd = new AutoResetEvent(false);
while (this.isRunning)
{
// wait on message queueud to publish
this.publishQueueWaitHandle.WaitOne();
// first check new subscribers to send retained messages ...
lock (this.subscribersForRetained)
{
count = this.subscribersForRetained.Count;
// publish retained messages to subscribers (new or reconnected)
while (count > 0)
{
count--;
MqttSubscription subscription = this.subscribersForRetained.Dequeue();
var query = from p in this.retainedMessages
where (new Regex(subscription.Topic)).IsMatch(p.Key) // check for topics based also on wildcard with regex
select p.Value;
if (query.Count() > 0)
{
// reverse loop to allow for changes in "this.retainedMessages"
for (int i = query.Count() - 1; i >= 0; i--)
{
MqttMsgPublish retained = query.ElementAt(i);
qosLevel = (subscription.QosLevel < retained.QosLevel) ? subscription.QosLevel : retained.QosLevel;
// send PUBLISH message to the current subscriber
subscription.Client.Publish(retained.Topic, retained.Message, qosLevel, retained.Retain);
}
}
}
}
// ... then check clients to send outgoing session messages
lock (this.clientsForSession)
{
count = this.clientsForSession.Count;
// publish outgoing session messages to clients (reconnected)
while (count > 0)
{
count--;
string clientId = this.clientsForSession.Dequeue();
MqttBrokerSession session = this.sessionManager.GetSession(clientId);
while (session.OutgoingMessages.Count > 0)
{
MqttMsgPublish outgoingMsg = session.OutgoingMessages.Dequeue();
var query = from s in session.Subscriptions
where (new Regex(s.Topic)).IsMatch(outgoingMsg.Topic) // check for topics based also on wildcard with regex
select s;
MqttSubscription subscription = query.First();
if (subscription != null)
{
qosLevel = (subscription.QosLevel < outgoingMsg.QosLevel) ? subscription.QosLevel : outgoingMsg.QosLevel;
session.Client.Publish(outgoingMsg.Topic, outgoingMsg.Message, qosLevel, outgoingMsg.Retain);
}
}
}
}
// ... then pass to process publish queue
lock (this.publishQueue)
{
publish = null;
count = this.publishQueue.Count;
// publish all queued messages
while (count > 0)
{
count--;
publish = (MqttMsgPublish)this.publishQueue.Dequeue();
if (publish != null)
{
// get all subscriptions for a topic
List <MqttSubscription> subscriptions = this.subscriberManager.GetSubscriptionsByTopic(publish.Topic);
if ((subscriptions != null) && (subscriptions.Count > 0))
{
foreach (MqttSubscription subscription in subscriptions)
{
qosLevel = (subscription.QosLevel < publish.QosLevel) ? subscription.QosLevel : publish.QosLevel;
// send PUBLISH message to the current subscriber
subscription.Client.Publish(publish.Topic, publish.Message, qosLevel, publish.Retain);
}
}
// get all sessions
List <MqttBrokerSession> sessions = this.sessionManager.GetSessions();
if ((sessions != null) && (sessions.Count > 0))
{
foreach (MqttBrokerSession session in sessions)
{
var query = from s in session.Subscriptions
where (new Regex(s.Topic)).IsMatch(publish.Topic)
select s;
MqttSubscriptionComparer comparer = new MqttSubscriptionComparer(MqttSubscriptionComparer.MqttSubscriptionComparerType.OnClientId);
// consider only session active for client disconnected (not online)
if (session.Client == null)
{
foreach (MqttSubscription subscription in query.Distinct(comparer))
{
qosLevel = (subscription.QosLevel < publish.QosLevel) ? subscription.QosLevel : publish.QosLevel;
// save PUBLISH message for client disconnected (not online)
session.OutgoingMessages.Enqueue(publish);
}
}
}
}
}
}
}
}
// signal thread end
this.publishEventEnd.Set();
}
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);
}
}
