Question

I need to make some connections on startup of a server. I’m using the wcf technology for this client-server application. The problem is that the constructor of the server isn’t called at any time, so for the moment, i initialize the connections when the first client makes a connection. But this generates problems in a further part.

This is my server setup:

private static ServiceHost _svc;

    static void Main(string[] args)
    {
        NetTcpBinding binding = new NetTcpBinding(SecurityMode.Message);
        Uri address = new Uri("net.tcp://localhost:8000");
        _svc = new ServiceHost(typeof(MonitoringSystemService), address);
        publishMetaData(_svc, "http://localhost:8001");
        _svc.AddServiceEndpoint(typeof(IMonitoringSystemService), binding, "Monitoring Server");
        _svc.Open();

        Console.WriteLine("Listener service gestart op net.tcp://localhost:8000/Monitoring");
        Console.ReadLine();
    }

    private static void publishMetaData(ServiceHost svc, string sEndpointAddress)
    {
        ServiceMetadataBehavior smb = svc.Description.Behaviors.Find<ServiceMetadataBehavior>();
        if (smb != null)
        {
            smb.HttpGetEnabled = true;
            smb.HttpGetUrl = new Uri(sEndpointAddress);
        }
        else
        {
            smb = new ServiceMetadataBehavior();
            smb.HttpGetEnabled = true;
            smb.HttpGetUrl = new Uri(sEndpointAddress);
            svc.Description.Behaviors.Add(smb);
        }
    }

How can i start the server without waiting for a client to logon so i can initialize it.

Thanks in advance.

Answer 1

WCF will instantiate your MonitoringSystemService class as needed. It won’t instantiate it until the first client makes a connection, and if you get a lot of client connections all at once, it will instantiate a few MonitoringSystemServices to deal with the load.

You can disable this behaviour, and instead just use one instance of MonitoringSystemService that gets created when your program starts. Instead of telling WCF which type it should be automatically instantiating, you just instantiate it yourself and pass it in:

_svc = new ServiceHost(new MonitoringSystemService()), address);

You gain control of when the MonitoringSystemService contructor runs, at the expense of scalability.

Alternatively (if you need the scalability), you could “initialize the connections” in your Main method, but be aware that WCF could instantiate multiple MonitoringSystemServices that would need to share those connections.