private async Task PollCommandTaskMethodAsync(SubscriptionTask subscriptionTask)
{
var subscription = subscriptionTask.Subscription;
var cancellationToken = subscriptionTask.CancellationTokenSource.Token;
while (true)
{
try
{
var commands = await PollCommandsAsync(subscription.DeviceGuids, subscription.EventNames,
subscription.Timestamp, subscriptionTask.IsLastPollFailed?(int?)0 : null, cancellationToken);
NotifyPollResult(subscriptionTask, false);
foreach (var command in commands)
{
command.SubscriptionId = subscription.Id;
InvokeSubscriptionCallback(subscription.Id, command.Command.Timestamp.Value, command);
}
}
catch (OperationCanceledException)
{
return;
}
catch (Exception)
{
NotifyPollResult(subscriptionTask, true);
if (cancellationToken.WaitHandle.WaitOne(FAILED_POLL_RETRY_TIMEOUT)) // retry with small wait
{
return;
}
}
}
}
/// <summary>
/// Subscribes to incoming messages.
/// </summary>
/// <param name="QueueName">Queue name.</param>
/// <param name="Cancel">Cancel event. Set this event object, to cancel subscription.</param>
/// <param name="Stopped">Optional Event that will be set when the subscription has ended.</param>
/// <param name="Callback">Method to call when new message has been read.</param>
/// <param name="State">State object to pass on to callback method.</param>
public void SubscribeIncoming(string QueueName, ManualResetEvent Cancel, TaskCompletionSource <bool> Stopped,
MqMessageEventHandler Callback, object State)
{
this.Information("Subscribing to messages from " + QueueName);
SubscriptionTask Item = new SubscriptionTask(this, QueueName, Cancel, Stopped, Callback, State);
MqTasks.ExecuteTask(Item);
}
private void NotifyPollResult(SubscriptionTask subscriptionTask, bool isFailed)
{
lock (_subscriptionTasks)
{
subscriptionTask.IsLastPollFailed = isFailed;
if (State == ChannelState.Connected && isFailed)
{
SetChannelState(ChannelState.Reconnecting);
}
else if (State == ChannelState.Reconnecting && !isFailed)
{
if (!_subscriptionTasks.Values.Any(t => t.IsLastPollFailed))
{
SetChannelState(ChannelState.Connected);
}
}
}
}
/// <summary>
/// Invoked after new subscription is added.
/// The method starts a polling thread.
/// </summary>
/// <param name="subscription">A <see cref="ISubscription"/> object representing a subscription.</param>
/// <returns></returns>
protected override async Task SubscriptionAdded(ISubscription subscription)
{
var subscriptionTask = new SubscriptionTask(subscription);
switch (subscription.Type)
{
case SubscriptionType.Notification:
subscriptionTask.Run(async() => await PollNotificationTaskMethodAsync(subscriptionTask));
break;
case SubscriptionType.Command:
subscriptionTask.Run(async() => await PollCommandTaskMethodAsync(subscriptionTask));
break;
}
lock (_subscriptionTasks)
{
_subscriptionTasks[subscription.Id] = subscriptionTask;
}
await base.SubscriptionAdded(subscription);
}
private void NotifyPollResult(SubscriptionTask subscriptionTask, bool isFailed)
{
lock (_subscriptionTasks)
{
subscriptionTask.IsLastPollFailed = isFailed;
if (State == ChannelState.Connected && isFailed)
{
SetChannelState(ChannelState.Reconnecting);
}
else if (State == ChannelState.Reconnecting && !isFailed)
{
if (!_subscriptionTasks.Values.Any(t => t.IsLastPollFailed))
SetChannelState(ChannelState.Connected);
}
}
}
private async Task PollCommandTaskMethodAsync(SubscriptionTask subscriptionTask)
{
var subscription = subscriptionTask.Subscription;
var cancellationToken = subscriptionTask.CancellationTokenSource.Token;
while (true)
{
try
{
var commands = await PollCommandsAsync(subscription.DeviceGuids, subscription.EventNames,
subscription.Timestamp, subscriptionTask.IsLastPollFailed ? (int?)0 : null, cancellationToken);
NotifyPollResult(subscriptionTask, false);
foreach (var command in commands)
{
InvokeSubscriptionCallback(subscription.Id, command.Timestamp.Value, command);
}
}
catch (OperationCanceledException)
{
return;
}
catch (Exception)
{
NotifyPollResult(subscriptionTask, true);
if (cancellationToken.WaitHandle.WaitOne(FAILED_POLL_RETRY_TIMEOUT)) // retry with small wait
return;
}
}
}
/// <summary>
/// Invoked after new subscription is added.
/// The method starts a polling thread.
/// </summary>
/// <param name="subscription">A <see cref="ISubscription"/> object representing a subscription.</param>
/// <returns></returns>
protected override async Task SubscriptionAdded(ISubscription subscription)
{
var subscriptionTask = new SubscriptionTask(subscription);
switch (subscription.Type)
{
case SubscriptionType.Notification:
subscriptionTask.Run(async () => await PollNotificationTaskMethodAsync(subscriptionTask));
break;
case SubscriptionType.Command:
subscriptionTask.Run(async () => await PollCommandTaskMethodAsync(subscriptionTask));
break;
}
lock (_subscriptionTasks)
{
_subscriptionTasks[subscription.Id] = subscriptionTask;
}
await base.SubscriptionAdded(subscription);
}
