detecting or avoiding client CommunicationException when server closes keep-alive http connection

Question

I'm developing a VS2010 Dotnet 4.0 client to a SOAP service in a device (a Pelco brand video dome as it happens) that runs embedded Linux. I have no control over the SOAP server in the device. The vendor has furnished WSDL files that load correctly as service references.

I'm using a command line desktop client to figure this out (before migrating the code into a service).

Simplifying a bit, the SOAP calls in the various services take forms like this:

 service.SetPosition(pan,tilt,zoom)
 var pos = service.GetPosition();

and so forth. They basically work and do what's expected.

The problem is this: once in a while, intermittently, with a pattern I haven't (yet) figured out, a random one of these service calls throws a CommunicationException whose Message is

 The underlying connection was closed: A connection that was 
 expected to be kept alive was closed by the server.

Here's how I construct my service objects:

  var binding = new System.ServiceModel.BasicHttpBinding();
  uri = new Uri(/*the correct uri for the service*/);
  address = new System.ServiceModel.EndpointAddress(u);
  service = new PositioningControlPortTypeClient(binding, address);

In this case the PositioningControlPortTypeClient gets defined via the WSDL when I load it as a service reference.

Is there a way to force dotnet 4.0 / wcf / soap to use HTTP/1.0?

Is there a way to detect that my service client is about to throw this exception before it throws it?

Should I use each service object just once, then dispose it?

Any other wisdom?

Answer 1

You can try disabling Keep-alive in your binding:

  var binding = new System.ServiceModel.BasicHttpBinding();
  uri = new Uri(/*the correct uri for the service*/);
  address = new System.ServiceModel.EndpointAddress(u);
  CustomBinding cbinding = new CustomBinding(binding);
  foreach (BindingElement be in cbinding.Elements)
  {
      if (be is HttpTransportBindingElement) ((HttpTransportBindingElement)be).KeepAliveEnabled = false;
  }
  service = new PositioningControlPortTypeClient(cbinding, address);