A simple Web service using WCF technology. Provides a GetData method to read a value of an OPC UA variable. Use UAWcfClient1 project (under Console folder) to test this Web service.
The service class:
// $Header: $
// Copyright (c) CODE Consulting and Development, s.r.o., Plzen. All rights reserved.
// ReSharper disable ArrangeModifiersOrder
// UAWcfService1: A simple Web service using WCF technology. Provides a GetData method to read a value of an OPC UA
// variable.
// Use UAWcfClient1 project (under Console folder) to test this Web service.
using OpcLabs.EasyOpc.UA;
namespace UAWcfService1
{
// NOTE: If you change the class name "Service1" here, you must also update the reference to "Service1" in Web.config and in the associated .svc file.
public class Service1 : IService1
{
// Use a shared client instance to allow for better optimization.
static private readonly EasyUAClient Client = new EasyUAClient();
public string GetData()
{
UAEndpointDescriptor endpointDescriptor =
"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
// or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
// or "https://opcua.demo-this.com:51212/UA/SampleServer/"
// The following call may throw a UAException, which would be propagated to the client as a FaultException.
// Production-quality code may need to catch the UAException and handle it differently.
object value = Client.ReadValue(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10845");
return value?.ToString() ?? "";
}
}
}
Service contract:
// $Header: $
// Copyright (c) CODE Consulting and Development, s.r.o., Plzen. All rights reserved.
using System.ServiceModel;
namespace UAWcfService1
{
// NOTE: If you change the interface name "IService1" here, you must also update the reference to "IService1" in Web.config.
[ServiceContract]
public interface IService1
{
[OperationContract]
string GetData();
}
}
See Also
Installed Examples - Console
Conceptual