public async Task AddAsync(MqttManagedMessage applicationMessage)
{
if (applicationMessage == null)
{
throw new ArgumentNullException(nameof(applicationMessage));
}
using (await _messagesLock.LockAsync(CancellationToken.None).ConfigureAwait(false))
{
_messages.Add(applicationMessage);
await SaveAsync().ConfigureAwait(false);
}
}
private void TryPublishQueuedMessage(MqttManagedMessage message)
{
Exception transmitException = null;
try
{
_mqttClient.PublishAsync(message.ApplicationMessage).GetAwaiter().GetResult();
lock (_messageQueue) //lock to avoid conflict with this.PublishAsync
{
//While publishing this message, this.PublishAsync could have booted this
//message off the queue to make room for another (when using a cap
//with the DropOldestQueuedMessage strategy). If the first item
//in the queue is equal to this message, then it's safe to remove
//it from the queue. If not, that means this.PublishAsync has already
//removed it, in which case we don't want to do anything.
_messageQueue.RemoveFirst(i => i.Id.Equals(message.Id));
}
_storageManager?.RemoveAsync(message).GetAwaiter().GetResult();
}
catch (MqttCommunicationException exception)
{
transmitException = exception;
_logger.Warning(exception, $"Publishing application ({message.Id}) message failed.");
if (message.ApplicationMessage.QualityOfServiceLevel == MqttQualityOfServiceLevel.AtMostOnce)
{
//If QoS 0, we don't want this message to stay on the queue.
//If QoS 1 or 2, it's possible that, when using a cap, this message
//has been booted off the queue by this.PublishAsync, in which case this
//thread will not continue to try to publish it. While this does
//contradict the expected behavior of QoS 1 and 2, that's also true
//for the usage of a message queue cap, so it's still consistent
//with prior behavior in that way.
lock (_messageQueue) //lock to avoid conflict with this.PublishAsync
{
_messageQueue.RemoveFirst(i => i.Id.Equals(message.Id));
}
}
}
catch (Exception exception)
{
transmitException = exception;
_logger.Error(exception, $"Unhandled exception while publishing application message ({message.Id}).");
}
finally
{
ApplicationMessageProcessed?.Invoke(this, new MqttMessageProcessedEventArgs(message, transmitException));
}
}
public async Task PublishAsync(MqttManagedMessage applicationMessage)
{
if (applicationMessage == null)
{
throw new ArgumentNullException(nameof(applicationMessage));
}
MqttManagedMessage removedMessage = null;
lock (_messageQueue)
{
if (Options != null)
{
if (_messageQueue.Count >= Options.MaxPendingMessages)
{
if (Options.PendingMessagesOverflowStrategy == MqttPendingMessagesOverflowStrategy.DropNewMessage)
{
_logger.Verbose("Skipping publish of new application message because internal queue is full.");
ApplicationMessageSkipped?.Invoke(this, new MqttMessageSkippedEventArgs(applicationMessage));
return;
}
if (Options.PendingMessagesOverflowStrategy == MqttPendingMessagesOverflowStrategy.DropOldestQueuedMessage)
{
removedMessage = _messageQueue.RemoveFirst();
_logger.Verbose("Removed oldest application message from internal queue because it is full.");
ApplicationMessageSkipped?.Invoke(this, new MqttMessageSkippedEventArgs(removedMessage));
}
}
}
_messageQueue.Enqueue(applicationMessage);
}
if (_storageManager != null)
{
if (removedMessage != null)
{
await _storageManager.RemoveAsync(removedMessage).ConfigureAwait(false);
}
await _storageManager.AddAsync(applicationMessage).ConfigureAwait(false);
}
}
public async Task RemoveAsync(MqttManagedMessage applicationMessage)
{
if (applicationMessage == null)
{
throw new ArgumentNullException(nameof(applicationMessage));
}
using (await _messagesLock.LockAsync(CancellationToken.None).ConfigureAwait(false))
{
var index = _messages.IndexOf(applicationMessage);
if (index == -1)
{
return;
}
_messages.RemoveAt(index);
await SaveAsync().ConfigureAwait(false);
}
}
public MqttMessageProcessedEventArgs(MqttManagedMessage applicationMessage, Exception exception)
{
ApplicationMessage = applicationMessage ?? throw new ArgumentNullException(nameof(applicationMessage));
Exception = exception;
}
public MqttMessageSkippedEventArgs(MqttManagedMessage applicationMessage)
{
ApplicationMessage = applicationMessage ?? throw new ArgumentNullException(nameof(applicationMessage));
}
