c# - 在 WCF ServiceHost 中提供工厂而不是类型

Question

有什么方法可以扩展 ServiceHost 以便它接受工厂？

我想在不触及服务实现的情况下使用动态服务代理对 WCF 调用进行一些预处理。

编辑

现在 ServiceHost 创建看起来像

var host = new ServiceHost(typeof(MyService));

我想用类似的东西

var factory = new ServiceProxyFactory<MyService>();
var host = new MyServiceHost(typeof(MyService), factory);

Answer 1

我要找的接口(interface)是IInstanceProvider.

public class MyServiceInstanceProvider<TService> : IInstanceProvider where TService : new()
{

    public object GetInstance(InstanceContext instanceContext, System.ServiceModel.Channels.Message message)
    {
        return ServiceFactory.Create<TService>();
    }

    public object GetInstance(InstanceContext instanceContext)
    {
        return ServiceFactory.Create<TService>();
    }

    public void ReleaseInstance(InstanceContext instanceContext, object instance)
    {
        return;
    }
}

public class MyEndpointBehavior<TService> : IEndpointBehavior where TService : new()
{

    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {
        return;
    }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        return;
    }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        endpointDispatcher.DispatchRuntime.InstanceProvider = new MyServiceInstanceProvider<TService>();
    }

    public void Validate(ServiceEndpoint endpoint)
    {
        return;
    }
}

public class MyServiceHost<TService> : ServiceHost where TService : new()
{
    public MyServiceHost(params Uri[] baseAddresses)
        :base(typeof(TService), baseAddresses)
    {            
    }

    public override System.Collections.ObjectModel.ReadOnlyCollection<ServiceEndpoint> AddDefaultEndpoints()
    {
        var endpoints = base.AddDefaultEndpoints();

        foreach (var endpoint in endpoints)
        {
            endpoint.Behaviors.Add(new MyEndpointBehavior<TService>());
        }

        return endpoints;
    }

    public override void AddServiceEndpoint(ServiceEndpoint endpoint)
    {
        base.AddServiceEndpoint(endpoint);
        endpoint.Behaviors.Add(new MyEndpointBehavior<TService>());
    }

}