/// <summary>
/// Creates the subscriptions on the server.
/// </summary>
/// <param name="token">A cancellation token. </param>
/// <returns>A task.</returns>
private async Task AutoCreateSubscriptionsAsync(CancellationToken token = default(CancellationToken))
{
var tcs = new TaskCompletionSource <bool>();
NotifyCollectionChangedEventHandler handler = async(o, e) =>
{
if (e.Action == NotifyCollectionChangedAction.Add)
{
foreach (var subscription in e.NewItems.OfType <Subscription>())
{
var target = subscription.Target;
if (target == null)
{
continue;
}
try
{
// create the subscription.
var subscriptionRequest = new CreateSubscriptionRequest
{
RequestedPublishingInterval = subscription.PublishingInterval,
RequestedMaxKeepAliveCount = subscription.KeepAliveCount,
RequestedLifetimeCount = Math.Max(subscription.LifetimeCount, 3 * subscription.KeepAliveCount),
PublishingEnabled = subscription.PublishingEnabled
};
var subscriptionResponse = await this.CreateSubscriptionAsync(subscriptionRequest).ConfigureAwait(false);
var id = subscription.SubscriptionId = subscriptionResponse.SubscriptionId;
// add the items.
if (subscription.MonitoredItems.Count > 0)
{
var items = subscription.MonitoredItems.ToList();
var requests = items.Select(m => new MonitoredItemCreateRequest {
ItemToMonitor = new ReadValueId {
NodeId = m.NodeId, AttributeId = m.AttributeId, IndexRange = m.IndexRange
}, MonitoringMode = m.MonitoringMode, RequestedParameters = new MonitoringParameters {
ClientHandle = m.ClientId, DiscardOldest = m.DiscardOldest, QueueSize = m.QueueSize, SamplingInterval = m.SamplingInterval, Filter = m.Filter
}
}).ToArray();
var itemsRequest = new CreateMonitoredItemsRequest
{
SubscriptionId = id,
ItemsToCreate = requests,
};
var itemsResponse = await this.CreateMonitoredItemsAsync(itemsRequest).ConfigureAwait(false);
for (int i = 0; i < itemsResponse.Results.Length; i++)
{
var item = items[i];
var result = itemsResponse.Results[i];
item.OnCreateResult(target, result);
if (StatusCode.IsBad(result.StatusCode))
{
this.Logger?.LogError($"Error creating MonitoredItem for {item.NodeId}. {StatusCodes.GetDefaultMessage(result.StatusCode)}");
}
}
}
}
catch (ServiceResultException ex)
{
this.Logger?.LogError($"Error creating subscription. {ex.Message}");
this.innerChannel.Fault(ex);
}
}
}
else if (e.Action == NotifyCollectionChangedAction.Remove)
{
try
{
// delete the subscriptions.
var request = new DeleteSubscriptionsRequest
{
SubscriptionIds = e.OldItems.OfType <Subscription>().Select(s => s.SubscriptionId).ToArray()
};
await this.DeleteSubscriptionsAsync(request).ConfigureAwait(false);
}
catch (ServiceResultException ex)
{
this.Logger?.LogError($"Error deleting subscriptions. {ex.Message}");
}
}
};
using (token.Register(state => ((TaskCompletionSource <bool>)state).TrySetResult(true), tcs, false))
{
try
{
handler.Invoke(this.subscriptions, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, this.subscriptions.ToList()));
this.subscriptions.CollectionChanged += handler;
await tcs.Task;
}
finally
{
this.subscriptions.CollectionChanged -= handler;
foreach (var subscription in this.subscriptions)
{
subscription.SubscriptionId = 0;
}
}
}
}
/// <summary>
/// The state machine manages the state of the subscription.
/// </summary>
/// <param name="token">A cancellation token.</param>
/// <returns>A task.</returns>
private async Task StateMachineAsync(CancellationToken token = default(CancellationToken))
{
while (!token.IsCancellationRequested)
{
await this.whenSubscribed.Task;
this.progress.Report(CommunicationState.Opening);
try
{
// get a channel.
this.innerChannel = await this.application.GetChannelAsync(this.endpointUrl, token);
try
{
// create the subscription.
var subscriptionRequest = new CreateSubscriptionRequest
{
RequestedPublishingInterval = this.publishingInterval,
RequestedMaxKeepAliveCount = this.keepAliveCount,
RequestedLifetimeCount = Math.Max(this.lifetimeCount, 3 * this.keepAliveCount),
PublishingEnabled = true
};
var subscriptionResponse = await this.innerChannel.CreateSubscriptionAsync(subscriptionRequest).ConfigureAwait(true);
// link up the dataflow blocks
var id = this.subscriptionId = subscriptionResponse.SubscriptionId;
var linkToken = this.innerChannel.LinkTo(this.actionBlock, pr => pr.SubscriptionId == id);
try
{
// create the monitored items.
var items = this.monitoredItems.ToList();
if (items.Count > 0)
{
var requests = items.Select(m => new MonitoredItemCreateRequest {
ItemToMonitor = new ReadValueId {
NodeId = m.NodeId, AttributeId = m.AttributeId, IndexRange = m.IndexRange
}, MonitoringMode = m.MonitoringMode, RequestedParameters = new MonitoringParameters {
ClientHandle = m.ClientId, DiscardOldest = m.DiscardOldest, QueueSize = m.QueueSize, SamplingInterval = m.SamplingInterval, Filter = m.Filter
}
}).ToArray();
var itemsRequest = new CreateMonitoredItemsRequest
{
SubscriptionId = id,
ItemsToCreate = requests,
};
var itemsResponse = await this.innerChannel.CreateMonitoredItemsAsync(itemsRequest);
for (int i = 0; i < itemsResponse.Results.Length; i++)
{
var item = items[i];
var result = itemsResponse.Results[i];
item.OnCreateResult(result);
if (StatusCode.IsBad(result.StatusCode))
{
this.logger?.LogError($"Error creating MonitoredItem for {item.NodeId}. {StatusCodes.GetDefaultMessage(result.StatusCode)}");
}
}
}
this.progress.Report(CommunicationState.Opened);
// wait here until channel is closing, unsubscribed or token cancelled.
try
{
await Task.WhenAny(
this.WhenChannelClosingAsync(this.innerChannel, token),
this.whenUnsubscribed.Task);
}
catch
{
}
finally
{
this.progress.Report(CommunicationState.Closing);
}
}
catch (Exception ex)
{
this.logger?.LogError($"Error creating MonitoredItems. {ex.Message}");
this.progress.Report(CommunicationState.Faulted);
}
finally
{
linkToken.Dispose();
}
if (this.innerChannel.State == CommunicationState.Opened)
{
try
{
// delete the subscription.
var deleteRequest = new DeleteSubscriptionsRequest
{
SubscriptionIds = new uint[] { id }
};
await this.innerChannel.DeleteSubscriptionsAsync(deleteRequest);
}
catch (Exception ex)
{
this.logger?.LogError($"Error deleting subscription. {ex.Message}");
await Task.Delay(2000);
}
}
this.progress.Report(CommunicationState.Closed);
}
catch (Exception ex)
{
this.logger?.LogError($"Error creating subscription. {ex.Message}");
this.progress.Report(CommunicationState.Faulted);
await Task.Delay(2000);
}
}
catch (Exception ex)
{
this.logger?.LogTrace($"Error getting channel. {ex.Message}");
this.progress.Report(CommunicationState.Faulted);
await Task.Delay(2000);
}
}
}
/// <summary>
/// The state machine manages the state of the subscription.
/// </summary>
/// <param name="token">A cancellation token.</param>
/// <returns>A task.</returns>
private async Task StateMachineAsync(CancellationToken token = default)
{
while (!token.IsCancellationRequested)
{
await this.whenSubscribed.Task;
this.progress.Report(CommunicationState.Opening);
try
{
if (this.endpointUrl is null)
{
throw new InvalidOperationException("The endpointUrl field must not be null. Please, use the Subscription attribute properly.");
}
// get a channel.
this.innerChannel = await this.application.GetChannelAsync(this.endpointUrl, token);
try
{
// create the subscription.
var subscriptionRequest = new CreateSubscriptionRequest
{
RequestedPublishingInterval = this.publishingInterval,
RequestedMaxKeepAliveCount = this.keepAliveCount,
RequestedLifetimeCount = Math.Max(this.lifetimeCount, 3 * this.keepAliveCount),
PublishingEnabled = true
};
var subscriptionResponse = await this.innerChannel.CreateSubscriptionAsync(subscriptionRequest).ConfigureAwait(false);
// link up the dataflow blocks
var id = this.subscriptionId = subscriptionResponse.SubscriptionId;
var linkToken = this.innerChannel.LinkTo(this.actionBlock, pr => pr.SubscriptionId == id);
try
{
// create the monitored items.
var items = this.monitoredItems.ToList();
if (items.Count > 0)
{
var requests = items.Select(m => new MonitoredItemCreateRequest {
ItemToMonitor = new ReadValueId {
NodeId = ExpandedNodeId.ToNodeId(m.NodeId, this.InnerChannel.NamespaceUris), AttributeId = m.AttributeId, IndexRange = m.IndexRange
}, MonitoringMode = m.MonitoringMode, RequestedParameters = new MonitoringParameters {
ClientHandle = m.ClientId, DiscardOldest = m.DiscardOldest, QueueSize = m.QueueSize, SamplingInterval = m.SamplingInterval, Filter = m.Filter
}
}).ToArray();
//split requests array to MaxMonitoredItemsPerCall chunks
int maxmonitoreditemspercall = 100;
MonitoredItemCreateRequest[] requests_chunk;
int chunk_size;
for (int i_chunk = 0; i_chunk < requests.Length; i_chunk += maxmonitoreditemspercall)
{
chunk_size = Math.Min(maxmonitoreditemspercall, requests.Length - i_chunk);
requests_chunk = new MonitoredItemCreateRequest[chunk_size];
Array.Copy(requests, i_chunk, requests_chunk, 0, chunk_size);
var itemsRequest = new CreateMonitoredItemsRequest
{
SubscriptionId = id,
ItemsToCreate = requests_chunk,
};
var itemsResponse = await this.innerChannel.CreateMonitoredItemsAsync(itemsRequest);
if (itemsResponse.Results is { } results)
{
for (int i = 0; i < results.Length; i++)
{
var item = items[i];
var result = results[i];
if (result is null)
{
this.logger?.LogError($"Error creating MonitoredItem for {item.NodeId}. The result is null.");
continue;
}
item.OnCreateResult(result);
if (StatusCode.IsBad(result.StatusCode))
{
this.logger?.LogError($"Error creating MonitoredItem for {item.NodeId}. {StatusCodes.GetDefaultMessage(result.StatusCode)}");
}
}
}
}
}
this.progress.Report(CommunicationState.Opened);
// wait here until channel is closing, unsubscribed or token cancelled.
try
{
await Task.WhenAny(
this.WhenChannelClosingAsync(this.innerChannel, token),
this.whenUnsubscribed.Task);
}
catch
{
}
finally
{
this.progress.Report(CommunicationState.Closing);
}
}
catch (Exception ex)
{
this.logger?.LogError($"Error creating MonitoredItems. {ex.Message}");
this.progress.Report(CommunicationState.Faulted);
}
finally
{
linkToken.Dispose();
}
if (this.innerChannel.State == CommunicationState.Opened)
{
try
{
// delete the subscription.
var deleteRequest = new DeleteSubscriptionsRequest
{
SubscriptionIds = new uint[] { id }
};
await this.innerChannel.DeleteSubscriptionsAsync(deleteRequest);
}
catch (Exception ex)
{
this.logger?.LogError($"Error deleting subscription. {ex.Message}");
await Task.Delay(2000);
}
}
this.progress.Report(CommunicationState.Closed);
}
catch (Exception ex)
{
this.logger?.LogError($"Error creating subscription. {ex.Message}");
this.progress.Report(CommunicationState.Faulted);
await Task.Delay(2000);
}
}
catch (Exception ex)
{
this.logger?.LogTrace($"Error getting channel. {ex.Message}");
this.progress.Report(CommunicationState.Faulted);
await Task.Delay(2000);
}
}
}
