/// <summary>
/// Method exposed as a node in the server to publish a node to IoT Hub that it is connected to
/// </summary>
private ServiceResult PublishNodeMethod(ISystemContext context, MethodState method, IList <object> inputArguments, IList <object> outputArguments)
{
if (inputArguments[0] == null || inputArguments[1] == null)
{
Trace("PublishNodeMethod: Invalid Arguments!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments!"));
}
NodeToPublish nodeToPublish;
string nodeId = inputArguments[0] as string;
string endpointUrl = inputArguments[1] as string;
if (string.IsNullOrEmpty(nodeId) || string.IsNullOrEmpty(endpointUrl))
{
Trace($"PublishNodeMethod: Arguments (0 (nodeId): '{nodeId}', 1 (endpointUrl):'{endpointUrl}') are not valid strings!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments as strings!"));
}
try
{
nodeToPublish = new NodeToPublish(nodeId, endpointUrl);
}
catch (UriFormatException)
{
Trace($"PublishNodeMethod: The endpointUrl is invalid (0 (nodeId): '{nodeId}', 1 (endpointUrl):'{endpointUrl}')!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide a valid OPC UA endpoint URL as second argument!"));
}
// Create session and add item to monitor, what ever is needed.
try
{
// find the session we need to monitor the node
OpcSession opcSession = OpcSessions.First(s => s.EndpointUri == nodeToPublish.EndPointUri);
// Add a new session.
if (opcSession == null)
{
// create new session info.
opcSession = new OpcSession(nodeToPublish.EndPointUri, OpcSessionCreationTimeout);
OpcSessions.Add(opcSession);
Trace($"DoPublish: No matching session found for endpoint '{nodeToPublish.EndPointUri.AbsolutePath}'. Requested to create a new one.");
}
else
{
Trace($"DoPublish: Session found for endpoint '{nodeToPublish.EndPointUri.AbsolutePath}'");
}
// add the node info to the sessions monitored items list.
opcSession.AddNodeForMonitoring(nodeToPublish.NodeId);
Trace("DoPublish: Requested to monitor item.");
// start monitoring the node
Task monitorTask = Task.Run(async() => await opcSession.ConnectAndMonitor());
monitorTask.Wait();
Trace("DoPublish: Session processing completed.");
// update our data
NodesToPublish.Add(nodeToPublish);
// persist it to disk
File.WriteAllText(NodesToPublishAbsFilename, JsonConvert.SerializeObject(NodesToPublish));
Trace($"DoPublish: Now publishing: {nodeToPublish.ToString()}");
return(ServiceResult.Good);
}
catch (Exception e)
{
Trace(e, $"DoPublish: Exception while trying to configure publishing node '{nodeToPublish.ToString()}'");
return(ServiceResult.Create(e, StatusCodes.BadUnexpectedError, $"Unexpected error publishing node: {e.Message}"));
}
}
/// <summary>
/// Method exposed as a node in the server to stop monitoring it and no longer publish telemetry of it.
/// </summary>
private ServiceResult UnPublishNodeMethod(ISystemContext context, MethodState method, IList <object> inputArguments, IList <object> outputArguments)
{
if (inputArguments[0] == null || inputArguments[1] == null)
{
Trace("UnPublishNodeMethod: Invalid arguments!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments!"));
}
string nodeId = inputArguments[0] as string;
string endpointUrl = inputArguments[1] as string;
if (string.IsNullOrEmpty(nodeId) || string.IsNullOrEmpty(endpointUrl))
{
Trace($"UnPublishNodeMethod: Arguments (0 (nodeId): '{nodeId}', 1 (endpointUrl):'{endpointUrl}') are not valid strings!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide all arguments as strings!"));
}
NodeToPublish nodeToUnpublish = new NodeToPublish();
try
{
nodeToUnpublish = new NodeToPublish(nodeId, endpointUrl);
}
catch (UriFormatException)
{
Trace($"UnPublishNodeMethod: The endpointUrl is invalid (0 (nodeId): '{nodeId}', 1 (endpointUrl):'{endpointUrl}')!");
return(ServiceResult.Create(StatusCodes.BadArgumentsMissing, "Please provide a valid OPC UA endpoint URL as second argument!"));
}
// Find the session and stop monitoring the node.
try
{
// find the session we need to monitor the node
OpcSession opcSession = OpcSessions.First(s => s.EndpointUri == nodeToUnpublish.EndPointUri);
if (opcSession == null)
{
// do nothing if there is no session for this endpoint.
Trace($"UnPublishNodeMethod: Session for endpoint '{nodeToUnpublish.EndPointUri.AbsolutePath}' not found.");
return(ServiceResult.Create(StatusCodes.BadSessionIdInvalid, "Session for endpoint of published node not found!"));
}
else
{
Trace($"UnPublishNodeMethod: Session found for endpoint '{nodeToUnpublish.EndPointUri.AbsolutePath}'");
}
// remove the node from the sessions monitored items list.
opcSession.TagNodeForMonitoringStop(nodeToUnpublish.NodeId);
Trace("UnPublishNodeMethod: Requested to stop monitoring of node.");
// stop monitoring the node
Task monitorTask = Task.Run(async() => await opcSession.ConnectAndMonitor());
monitorTask.Wait();
Trace("UnPublishNodeMethod: Session processing completed.");
// remove node from our persisted data set.
var itemToRemove = NodesToPublish.Find(l => l.NodeId == nodeToUnpublish.NodeId && l.EndPointUri == nodeToUnpublish.EndPointUri);
NodesToPublish.Remove(itemToRemove);
// persist data
File.WriteAllText(NodesToPublishAbsFilename, JsonConvert.SerializeObject(NodesToPublish));
}
catch (Exception e)
{
Trace(e, $"DoPublish: Exception while trying to configure publishing node '{nodeToUnpublish.ToString()}'");
return(ServiceResult.Create(e, StatusCodes.BadUnexpectedError, $"Unexpected error publishing node: {e.Message}"));
}
return(ServiceResult.Good);
}