如何在.NET Core上从WCF SOAP客户端记录HTTP级流？

Question

背景：我正在维护一个集成平台，该平台可以从各种不可靠的API中提取数据。其中一些操作可能会产生高昂的成本，因此出于诊断目的，每条传出和传入的消息都记录到磁盘上的单独文件中。对于类似REST的API，我在网络流上使用一个简单的包装程序，该包装程序还将数据保存到文件中。对于.NET Classic SOAP客户端，我有一个自动包装的助手，SoapHttpClientProtocol以使用相同的网络流日志记录机制。

使用.NET Standard 2.0和.NET Core，编写SOAP客户端的唯一受支持方法是WCF。如何以编程方式配置WCF SOAP客户端，以将HTTP传入/传出流记录到单独的文件中，最好使用可配置的名称？

我当前的示例客户端代码：

public abstract class ServiceCommunicatorBase<T>
    where T : IClientChannel
{
    private const int Timeout = 20000;

    private static readonly ChannelFactory<T> ChannelFactory = new ChannelFactory<T>(
        new BasicHttpBinding(),
        new EndpointAddress(new Uri("http://target/endpoint")));

    protected T1 ExecuteWithTimeoutBudget<T1>(
        Func<T, Task<T1>> serviceCall,
        [CallerMemberName] string callerName = "")
    {
        // TODO: fixme, setup logging
        Console.WriteLine(callerName);

        using (var service = this.CreateService(Timeout))
        {
            // this uses 2 threads and is less than ideal, but legacy app can't handle async yet
            return Task.Run(() => serviceCall(service)).GetAwaiter().GetResult();
        }
    }

    private T CreateService(int timeout)
    {
        var clientChannel = ChannelFactory.CreateChannel();
        clientChannel.OperationTimeout = TimeSpan.FromMilliseconds(timeout);
        return clientChannel;
    }
}

public class ConcreteCommunicator
    : ServiceCommunicatorBase<IWCFRemoteInterface>
{
    public Response SomeRemoteAction(Request request)
    {
        return this.ExecuteWithTimeoutBudget(
            s => s.SomeRemoteAction(request));
    }
}

Answer 1

我设法IClientMessageInspector通过可配置的行为使用附件记录了消息。在MSDN上有一些针对Message Inspectors的文档，但是它仍然含糊不清（而且有些过时，netstandard-2.0API表面有些不同。

我不得不从使用ChannelFactory<T>转到使用实际生成的代理类。工作代码（为简洁起见）：

var clientChannel = new GeneratedProxyClient(
  new BasicHttpBinding { SendTimeout = TimeSpan.FromMilliseconds(timeout) },
  new EndpointAddress(new Uri("http://actual-service-address"));

clientChannel.Endpoint.EndpointBehaviors.Add(new LoggingBehaviour());

服务类别：

// needed to bind the inspector to the client channel
// other methods are empty
internal class LoggingBehaviour : IEndpointBehavior
{
    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.ClientMessageInspectors.Add(new LoggingClientMessageInspector());
    }
}

internal class LoggingClientMessageInspector : IClientMessageInspector
{
    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        var correlationId = Guid.NewGuid();
        this.SaveLog(ref request, correlationId, "RQ");

        return correlationId;
    }

    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
        var correlationId = (Guid)correlationState;
        this.SaveLog(ref reply, correlationId, "RS");
    }

    private void SaveLog(ref Message request, Guid correlationId, string suffix)
    {
        var outputPath = GetSavePath(suffix, correlationId, someOtherData);
        using (var buffer = request.CreateBufferedCopy(int.MaxValue))
        {
            var directoryName = Path.GetDirectoryName(outputPath);
            if (directoryName != null)
            {
                Directory.CreateDirectory(directoryName);
            }

            using (var stream = File.OpenWrite(outputPath))
            {
                using (var message = buffer.CreateMessage())
                {
                    using (var writer = XmlWriter.Create(stream))
                    {
                        message.WriteMessage(writer);
                    }
                }
            }

            request = buffer.CreateMessage();
        }
    }
}