how to log JSON response in WCF at service level

Question

I have a WCF service that returns JSON to the clients.

This is the app.config

  <system.serviceModel>
<services>
  <service name="MyServices.MyService">
    <endpoint address="" behaviorConfiguration="JsonBehavior" binding="webHttpBinding"
      contract="Myervices.IMyervice">
      <identity>
        <dns value="localhost" />
      </identity>
    </endpoint>
    <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
    <host>
      <baseAddresses>
        <add baseAddress="http://localhost:8732/Design_Time_Addresses/MyEmulator/Service1/" />
      </baseAddresses>
    </host>
  </service>
</services>
<behaviors>
  <serviceBehaviors>
    <behavior>
      <serviceMetadata httpGetEnabled="True"/>
      <serviceDebug includeExceptionDetailInFaults="True"/>
    </behavior>
  </serviceBehaviors>
  <endpointBehaviors>
    <behavior name="JsonBehavior">
      <webHttp />
    </behavior>
  </endpointBehaviors>
</behaviors>

This is a sample opertaion exposed by the service

 [OperationContract]
    [WebInvoke(BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json, Method = "GET", UriTemplate = "me/{id}")]
    JsonObject GetObject(string id, string connection_type);

Now, I would like to log every request that the service receives from clients and response that is being sent back to clients...in this case it sin JSOn.

I have create a custom MessageInspector as follows

public class MyMessageInspector : IDispatchMessageInspector
{
    private bool LoggingEnabled;
    #region IDispatchMessageInspector Members

    public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel, System.ServiceModel.InstanceContext instanceContext)
    {
        Guid correlationState = Guid.NewGuid();
        if (this.LoggingEnabled)
        {
            StringBuilder message = new StringBuilder();
            message.AppendFormat("CorrelationState = {0}{1}", correlationState, Environment.NewLine);
            message.AppendFormat("Local Address = {0}{1}", channel.LocalAddress, Environment.NewLine);
            message.AppendFormat("Remote Address = {0}{1}", channel.RemoteAddress, Environment.NewLine);
            message.AppendLine("Request");
            message.AppendLine(request.ToString());
            message.AppendLine();
            this.logger.LogMessage(message.ToString());
        }

        return correlationState;
    }

    public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
    {
        if (this.LoggingEnabled)
        {
            StringBuilder message = new StringBuilder();
            message.AppendFormat("CorrelationState = {0}{1}", correlationState, Environment.NewLine);
            message.AppendLine("Reply");
            message.AppendLine(reply.ToString());
            message.AppendLine();
            this.logger.LogMessage(message.ToString());
        }
    }

    #endregion
}

But this doesnt seem to log any of the resposne.. the response.Tostring() only says "...stream"

the Above works if my service returns data in SOAP XML format..but i want it to log JSON response which is the text inside the *.js file downloaded in the browser when i call the REST service endpoint. ex: http://localhost:8080/MyService/me/2/

any ideas how I can achieve this?

Answer 1

This code provides a mechanism for working with REST messages, and as a bonus allows SOAP to pass through as normal. It's a little intrusive (the stream is destroyed by reading so the code needs to regenerate it) but I haven't found any better way.

http://code.msdn.microsoft.com/WCF-REST-Message-Inspector-c4b6790b