IIS上的WCF：将数据从ServiceHostFactory传递到Service实例

Question

我正在IIS上托管WCF应用程序。 我正在自定义ServiceHostFactory初始化一个IoC容器。

基本上我想要的是能够将IoC容器“注入”到在该ServiceHost范围内创建的每个Service实例。

你将如何实现这一目标？

爱丽儿

Answer 1

就像你说的那样，你需要一个自定义的ServiceHostFactory，用于创建你的服务。像这样：

public class SessionPerCallServiceHostFactory : ServiceHostFactory
{
    public SessionPerCallServiceHostFactory()
    {
    }

    protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
    {
        return new SessionPerCallServiceHost(serviceType, baseAddresses);
    }
}

您还需要一个负责创建必要服务的ServiceHost：

public class SessionPerCallServiceHost : ServiceHost
{
    public SessionPerCallServiceHost()
    {
    }

    public SessionPerCallServiceHost(Type serviceType, params Uri[] baseAddresses)
    : base(serviceType, baseAddresses)
    {
    }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new SessionPerCallServiceBehavior());
        base.OnOpening();
    }

}

使用IServiceBehavior的自定义实现，它将能够提供用于创建服务实例的InstanceProvider：

public class SessionPerCallServiceBehavior : IServiceBehavior
{
    public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {            
        foreach (ChannelDispatcherBase cdb in serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if (cd != null)
            {
                foreach (EndpointDispatcher ed in cd.Endpoints)
                {                        
                    ed.DispatchRuntime.InstanceProvider =
                        new SessionPerCallInstanceProvider(serviceDescription.ServiceType);
                }
            }
        }
    }

    public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection endpoints, BindingParameterCollection bindingParameters)
    {
    }

    public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
    }

}

最后，实例提供程序允许您使用IoC在请求的服务实例中注入您想要的任何内容：

public class SessionPerCallInstanceProvider : IInstanceProvider
{
    private readonly Type _serviceType;

    public SessionPerCallInstanceProvider(Type serviceType)
    {
        _serviceType = serviceType;
    }

    public object GetInstance(InstanceContext instanceContext, System.ServiceModel.Channels.Message message)
    {
        //I'm creating it without any tricks but you could use your IoC container here
        return Activator.CreateInstance(_serviceType);
    }

    public object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public void ReleaseInstance(System.ServiceModel.InstanceContext instanceContext, object instance)
    {

    }
}

希望它有所帮助！