how to log JSON response in WCF at service level - wcf

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