/// <summary>
/// Subscribes or unsubscribes to events produced an event source.
/// </summary>
public override ServiceResult SubscribeToEvents(
OperationContext context,
object sourceId,
uint subscriptionId,
IEventMonitoredItem monitoredItem,
bool unsubscribe)
{
ServerSystemContext systemContext = SystemContext.Copy(context);
// send request to external system.
try
{
MonitoredItem localItem = monitoredItem as MonitoredItem;
if (localItem == null)
{
return ServiceResult.Good;
}
Opc.Ua.Client.Session client = GetClientSession(systemContext);
if (unsubscribe)
{
lock (client)
{
// get the subscription.
Opc.Ua.Client.Subscription target = null;
foreach (Opc.Ua.Client.Subscription current in client.Subscriptions)
{
target = current;
break;
}
if (target == null)
{
return ServiceResult.Good;
}
// find matching item.
Opc.Ua.Client.MonitoredItem remoteItem = target.FindItemByClientHandle(monitoredItem.Id);
if (remoteItem == null)
{
return ServiceResult.Good;
}
// apply changes.
target.RemoveItem(remoteItem);
target.ApplyChanges();
if (target.MonitoredItemCount == 0)
{
target.Session.RemoveSubscription(target);
}
}
return ServiceResult.Good;
}
// create a request.
Opc.Ua.Client.MonitoredItem request = new Opc.Ua.Client.MonitoredItem(localItem.Id);
if (localItem.NodeId == ObjectIds.Server || localItem.NodeId == m_root.NodeId)
{
request.StartNodeId = ObjectIds.Server;
}
else
{
request.StartNodeId = m_mapper.ToRemoteId(localItem.NodeId);
}
request.AttributeId = Attributes.EventNotifier;
request.MonitoringMode = localItem.MonitoringMode;
request.SamplingInterval = (int)localItem.SamplingInterval;
request.QueueSize = localItem.QueueSize;
request.DiscardOldest = true;
request.Filter = localItem.Filter;
request.Handle = localItem;
lock (client)
{
// create subscription.
if (client.SubscriptionCount == 0)
{
Opc.Ua.Client.Subscription subscription = new Opc.Ua.Client.Subscription();
subscription.PublishingInterval = 250;
subscription.KeepAliveCount = 100;
subscription.LifetimeCount = 1000;
subscription.MaxNotificationsPerPublish = 10000;
subscription.Priority = 1;
subscription.PublishingEnabled = true;
subscription.TimestampsToReturn = TimestampsToReturn.Both;
subscription.DisableMonitoredItemCache = true;
subscription.FastDataChangeCallback = OnDataChangeNotification;
subscription.FastEventCallback = OnEventNotification;
client.AddSubscription(subscription);
subscription.Create();
}
// get the subscription.
Opc.Ua.Client.Subscription target = null;
foreach (Opc.Ua.Client.Subscription current in client.Subscriptions)
{
target = current;
break;
}
if (target == null)
{
return ServiceResult.Good;
}
target.AddItem(request);
target.ApplyChanges();
if (ServiceResult.IsBad(request.Status.Error))
{
Utils.Trace((int)Utils.TraceMasks.Error, "Could not create event item. {0}", request.Status.Error.ToLongString());
}
}
}
catch (Exception e)
{
Utils.Trace(e, "Could not access external system.");
}
return ServiceResult.Good;
}
/// <summary>
/// Called when a batch of monitored items has been created.
/// </summary>
protected override void OnCreateMonitoredItemsComplete(ServerSystemContext context, IList<IMonitoredItem> monitoredItems)
{
List<Opc.Ua.Client.MonitoredItem> requests = new List<Opc.Ua.Client.MonitoredItem>();
List<int> indexes = new List<int>();
for (int ii = 0; ii < monitoredItems.Count; ii++)
{
MonitoredItem monitoredItem = monitoredItems[ii] as MonitoredItem;
if (monitoredItem == null || !Object.ReferenceEquals(monitoredItem.NodeManager, this))
{
continue;
}
lock (Lock)
{
// determine if a local node.
if (PredefinedNodes.ContainsKey(monitoredItem.NodeId))
{
continue;
}
// create a request.
Opc.Ua.Client.MonitoredItem request = new Opc.Ua.Client.MonitoredItem(monitoredItem.Id);
request.StartNodeId = m_mapper.ToRemoteId(monitoredItem.NodeId);
request.MonitoringMode = monitoredItem.MonitoringMode;
request.SamplingInterval = (int)(monitoredItem.SamplingInterval/2);
request.Handle = monitoredItem;
requests.Add(request);
indexes.Add(ii);
}
}
// send request to external system.
try
{
Opc.Ua.Client.Session client = GetClientSession(context);
lock (client)
{
// create subscription.
if (client.SubscriptionCount == 0)
{
Opc.Ua.Client.Subscription subscription = new Opc.Ua.Client.Subscription();
subscription.PublishingInterval = 250;
subscription.KeepAliveCount = 100;
subscription.LifetimeCount = 1000;
subscription.MaxNotificationsPerPublish = 10000;
subscription.Priority = 1;
subscription.PublishingEnabled = true;
subscription.TimestampsToReturn = TimestampsToReturn.Both;
subscription.DisableMonitoredItemCache = true;
subscription.FastDataChangeCallback = OnDataChangeNotification;
subscription.FastEventCallback = OnEventNotification;
client.AddSubscription(subscription);
subscription.Create();
}
// add items.
Opc.Ua.Client.Subscription target = null;
foreach (Opc.Ua.Client.Subscription current in client.Subscriptions)
{
target = current;
break;
}
for (int ii = 0; ii < requests.Count; ii++)
{
target.AddItem(requests[ii]);
}
target.ApplyChanges();
// check status.
int index = 0;
foreach (Opc.Ua.Client.MonitoredItem monitoredItem in target.MonitoredItems)
{
if (ServiceResult.IsBad(monitoredItem.Status.Error))
{
((MonitoredItem)monitoredItems[indexes[index++]]).QueueValue(null, monitoredItem.Status.Error);
}
}
}
}
catch (Exception e)
{
// handle unexpected communication error.
ServiceResult error = ServiceResult.Create(e, StatusCodes.BadUnexpectedError, "Could not access external system.");
for (int ii = 0; ii < requests.Count; ii++)
{
((MonitoredItem)monitoredItems[indexes[ii]]).QueueValue(null, error);
}
}
}
public System.Threading.Tasks.Task OPCUnmonitorAsync(Opc.Ua.Client.Subscription subscription, Opc.Ua.Client.MonitoredItem monitoredItem)
{
return(base.Channel.OPCUnmonitorAsync(subscription, monitoredItem));
}
public void OPCUnmonitor(Opc.Ua.Client.Subscription subscription, Opc.Ua.Client.MonitoredItem monitoredItem)
{
base.Channel.OPCUnmonitor(subscription, monitoredItem);
}
public System.Threading.Tasks.Task OPCUnsubscribeAsync(Opc.Ua.Client.Subscription subscription)
{
return(base.Channel.OPCUnsubscribeAsync(subscription));
}
public void OPCUnsubscribe(Opc.Ua.Client.Subscription subscription)
{
base.Channel.OPCUnsubscribe(subscription);
}
