错误“此消息不支持该操作，因为它已被读取”

Question

I have the same problem that is listed in the following thread.

WSDL first WCF server where client does not send SOAPAction

I performed the steps that are listed in the same thread (also shown below)

1) Download the Microsoft WCF examples. Add the following files to your project from WF_WCF_Samples\\WCF\\Extensibility\\Interop\\RouteByBody\\CS\\service

DispatchByBodyOperationSelector.cs

DispatchByBodyBehaviorAttribute.cs

2) Add the following attributes to your interface (next to your ServiceContract)

XmlSerializerFormat

DispatchByBodyBehavior

3) Add the following to your service interface

[OperationContract(Action = "")]

public void DoNothing()
{
}

4) For my service the WrapperName and Wrappernamespace are null for all messages. I had to go into DispatchByBodyBehaviorAttribute and edit ApplyDispatchBehavior() to add the following lines to check for this:

 if (qname.IsEmpty) {
     qname = new XmlQualifiedName(operationDescription.Messages[0].Body.Parts[0].Name, operationDescription.Messages[0].Body.Parts[0].Namespace);
 }

Now, I am getting an error message "This message cannot support the operation because it has been read". I turned the tracing on and captured the stack trace (below). If anyone has any idea on how this can be resolved, I appreciate if you could post some comments. Thanks for any help!

at System.ServiceModel.Channels.Message.GetReaderAtBodyContents()
at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)
at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeRequest(Message message, Object[] parameters)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.DeserializeInputs(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)
at System.ServiceModel.Dispatcher.ChannelHandler.DispatchAndReleasePump(RequestContext request, Boolean cleanThread, OperationContext currentOperationContext)
at System.ServiceModel.Dispatcher.ChannelHandler.HandleRequest(RequestContext request, OperationContext currentOperationContext)
at System.ServiceModel.Dispatcher.ChannelHandler.AsyncMessagePump(IAsyncResult result)
at System.ServiceModel.Dispatcher.ChannelHandler.OnAsyncReceiveComplete(IAsyncResult result)
at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
at System.Runtime.AsyncResult.Complete(Boolean completedSynchronously)
at System.Runtime.InputQueue`1.AsyncQueueReader.Set(Item item)
at System.Runtime.InputQueue`1.EnqueueAndDispatch(Item item, Boolean canDispatchOnThisThread)
at System.Runtime.InputQueue`1.EnqueueAndDispatch(T item, Action dequeuedCallback, Boolean canDispatchOnThisThread)
at System.ServiceModel.Channels.SingletonChannelAcceptor`3.Enqueue(QueueItemType item, Action dequeuedCallback, Boolean canDispatchOnThisThread)
at System.ServiceModel.Channels.HttpChannelListener.HttpContextReceived(HttpRequestContext context, Action callback)
at System.ServiceModel.Channels.SharedHttpTransportManager.OnGetContextCore(IAsyncResult result)
at System.ServiceModel.Channels.SharedHttpTransportManager.OnGetContext(IAsyncResult result)
at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
at System.Net.LazyAsyncResult.Complete(IntPtr userToken)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
at System.Net.ListenerAsyncResult.WaitCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)
</StackTrace>


class DispatchByBodyElementOperationSelector : IDispatchOperationSelector
{
    Dictionary<XmlQualifiedName, string> dispatchDictionary;

    public DispatchByBodyElementOperationSelector(Dictionary<XmlQualifiedName, string> dispatchDictionary)
    {
        this.dispatchDictionary = dispatchDictionary;            
    }

    #region IDispatchOperationSelector Members

    private Message CreateMessageCopy(Message message, XmlDictionaryReader body)
    {
        //Message copy = Message.CreateMessage(message.Version, message.Headers.Action, body);
        //copy.Headers.CopyHeaderFrom(message, 0);
        //copy.Properties.CopyProperties(message.Properties);
        //return copy;    

        MessageBuffer buffer = message.CreateBufferedCopy(Int32.MaxValue);
        Message copy = buffer.CreateMessage();
        buffer.Close();
        copy.Headers.CopyHeaderFrom(message, 0);
        copy.Properties.CopyProperties(message.Properties);

        return copy;
    }

    public string SelectOperation(ref System.ServiceModel.Channels.Message message)
    {
        XmlDictionaryReader bodyReader = message.GetReaderAtBodyContents();

        XmlQualifiedName lookupQName = new XmlQualifiedName(bodyReader.LocalName, bodyReader.NamespaceURI);
        message = CreateMessageCopy(message,bodyReader);
        if (dispatchDictionary.ContainsKey(lookupQName))
        {
            return dispatchDictionary[lookupQName];
        }
        else
        {
            return null;
        }
    }

    #endregion
}

[AttributeUsage(AttributeTargets.Class|AttributeTargets.Interface)]
sealed class DispatchByBodyBehaviorAttribute : Attribute, IContractBehavior
{
    #region IContractBehavior Members

    public void AddBindingParameters(ContractDescription contractDescription, ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
    {
        // no binding parameters need to be set here
        return;
    }

    public void ApplyClientBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime)
    {
        // this is a dispatch-side behavior which doesn't require
        // any action on the client
        return;
    }

    public void ApplyDispatchBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.DispatchRuntime dispatchRuntime)
    {
        // We iterate over the operation descriptions in the contract and
        // record the QName of the request body child element and corresponding operation name
        // to the dictionary to be used for dispatch 
        Dictionary<XmlQualifiedName,string> dispatchDictionary = new Dictionary<XmlQualifiedName,string>();
        foreach( OperationDescription operationDescription in contractDescription.Operations )
        {
            XmlQualifiedName qname =
                new XmlQualifiedName(operationDescription.Messages[0].Body.WrapperName, operationDescription.Messages[0].Body.WrapperNamespace);




            if (qname.IsEmpty)
            {
                qname = new XmlQualifiedName(operationDescription.Messages[0].Body.Parts[0].Name, operationDescription.Messages[0].Body.Parts[0].Namespace);
            }

            dispatchDictionary.Add(qname, operationDescription.Name);                
        }

        // Lastly, we create and assign and instance of our operation selector that
        // gets the dispatch dictionary we've just created.
        dispatchRuntime.OperationSelector = 
            new DispatchByBodyElementOperationSelector(dispatchDictionary);
    }

    public void Validate(ContractDescription contractDescription, ServiceEndpoint endpoint)
    {
        // 
    }

    #endregion
}

Answer 1

You should use MessageBuffer.CreateMessage :

The body of a Message instance can only be consumed or written once. If you wish to consume a Message instance more than once, you should use the MessageBuffer class to completely store an entire Message instance into memory.

http://msdn.microsoft.com/en-us/library/system.servicemodel.channels.messagebuffer.aspx

Code from my current project:

public void AfterReceiveReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
    MessageBuffer buffer = reply.CreateBufferedCopy(Int32.MaxValue);
    reply = buffer.CreateMessage();
    Message m = buffer.CreateMessage();
    LogMessage(m, " Response => ");
}

Add ref for Message param and return new message.

 private Message CreateMessageCopy(ref Message message, XmlDictionaryReader body)
{
...
   message = buffer.CreateMessage();

Answer 2

I had a very similar issue, using code from WCF Samples (RouteByBody to be precise) as well, and was able to solve it in a different way so I'll post it here in case it helps anybody.

Situation: The client application (consumer) would work in Release , however, when the debugger was attached it would always fail with the error "This message cannot support the operation because it has been read" .

After much tracing and logging WCF messages, the only solution that worked for me turned out to be so simple:

My Service was hosted on IIS, and with debug="true" in the <compilation> section of the web.config.

Changing it to debug="false" on the service fixed all my problems.

Answer 3

Dmitry Harnitski's answer does not work if you are debugging the service (It will give you a "This message cannot support the operation because it has been copied." error.)

This works even in debug mode:

XmlDictionaryReader GetReader(ref Message message)
{
    MessageBuffer buffer = message.CreateBufferedCopy(Int32.MaxValue);
    message = buffer.CreateMessage();
    newMessage = buffer.CreateMessage();
    XmlDictionaryReader rv = buffer.CreateMessage().GetReaderAtBodyContents();
    buffer.Close();
    return rv;
}

static System.ServiceModel.Channels.Message newMessage = null;
static System.ServiceModel.Channels.Message lastMessage = null;

public string SelectOperation(ref System.ServiceModel.Channels.Message message)
{
    try
    {
        if(message == lastMessage)
            message = newMessage;

        XmlDictionaryReader bodyReader = GetReader(ref message);

        lastMessage = message;

        XmlQualifiedName lookupQName = new XmlQualifiedName(bodyReader.LocalName, bodyReader.NamespaceURI);
        if (dispatchDictionary.ContainsKey(lookupQName))
        {
            return dispatchDictionary[lookupQName];
        }
        else
        {
            return null;
        }
    }
    catch(Exception ex)
    {
        throw ex;
    }
}