System.ServiceModel assembly is not marked as serializable

Most frustrating thing you ever going to come across is debugging web services, but not if you know the tricks & tools which you could use to get to the root of problem causing the error in the services at the first place. Web services related errors can be deceiving and forcing you to look at places that work perfectly. 

Today I have been working on a custom WCF web services which was trying to download a document from a SharePoint list to a workflow server, it worked perfectly until we decided to change the way our workflow server authenticates(for some reason), so we created a proxy which will be used to call custom WCF service from workflow server instead of adding a web reference.

As soon as we changed the way we were calling custom WCF web services, we started getting this error,

 Description: Type 'System.ServiceModel.Dispatcher.NetDispatcherFaultException' in Assembly 'System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=""' is not marked as serializable.
Server stack trace:
   at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder)

So looking at error initially, I thought it because we are not serializing the document who's details were wrapped up within a object, so I added this "[Serializable]" to our document class,


    [DataContract]
    [Serializable]
    public class DocumentObject
    {
        [DataMember]
        public string documentName;
        [DataMember]
        public byte[] data;
    }

   [ServiceContract]
   public interface IDocuments
   {
        [OperationContract]
        DocumentObject[] GetDocumentsFromList(string listName, string[] documentNames);
   }


On the other side when we tried to deserialize the document I still kept getting this error,

Type 'System.ServiceModel.Dispatcher.NetDispatcherFaultException' in Assembly 'System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=f4tue731934e089' is not marked as serializable.
 Server stack trace:
   at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder)
   at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo)
   at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck)

Since the error saying that, something went wrong while deserializing the object but why though ? I tried using BinaryFormatter to desearlize the method's response from webservices but it didn't helped as same code worked when there was no proxy... anyway, I added includeExceptionDetailInFaults="true" to my custom application's web.config, which was calling the WCF web services, to get the inner or real exception,

<?xml version="1.0"?>
<configuration>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="debug">
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>


Adding above helped me get to the bottom of problem, which was the size of document it was trying to desearlize. Size limit was exceeding,

The InnerException message was 'There was an error deserializing the object of  type MySolution.WebServices.DocumentObject[]. The maximum array length quota (16384) has been exceeded while reading XML data. 

To fix the above, you can either change the web.config of your WCF service and change MaxArrayLength or you can do it within code,

XmlDictionaryReaderQuotas readerQuotas = new XmlDictionaryReaderQuotas();
readerQuotas.MaxArrayLength = 1024 * 1024 * 102;  //102 Mega bytes
readerQuotas.MaxDepth = int.MaxValue;
binding.ReaderQuotas = readerQuotas;


This solved the issue for me.

Debugging WCF service using SvcTraceView on application server

Debugging web services can be pain, specially when they are hosted on a application server within a SharePoint farm. There are several ways one can debug web services though, e.g. using a visual studio remote debugger but what if it doesn't hit your web services breakpoints or your network administrator do?

Easiest way to figure out what's wrong with web services is to use SvcTraceViewer.exe e.g. why my code not able to find the hosted service or if the problem is with service account authentication.

Not so difficult to set it up, all you need to do is to add a some tag in your hosted WCF services and then open the SvcTraceViewer to view the created file.

Step-1:
Find hosted WCF service's web.config and add following tag to it within configuration tag. It will recycle the application pool of hosted service itself when you will save changes to web.config file.

<configuration>
<system.diagnostics>
    <trace autoflush="true" />
    <sources>
            <source name="System.ServiceModel" 
                    switchValue="Information, ActivityTracing"
                    propagateActivity="true">
            <listeners>
               <add name="sdt" 
                   type="System.Diagnostics.XmlWriterTraceListener" 
                   initializeData= "WcfConfigExample.e2e" />
            </listeners>
         </source>
    </sources>
</system.diagnostics>
</configuration>

Step-2:
Find SvcTraceViewer.exe within installed Visual studio files, location might change depending on version of VS, however since I am using VS 2010 ultimate so I find EXE file at,

C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Bin\NETFX 4.0 Tools

In some cases you will need to open the EXE file as administrator.

Step-3:
Do something to trigger WCF services and check folder where web.config file exists as that's where it will create "SdrConfigExample.e2e" log file, once you find it. just open the SvcTraceViewer.exe file.

Step-4:
Press Ctrl + O keys; Navigate to SdrConfigExample.e2e file to load log trace file in viewer.

Step-5:
Search for specific terms using Ctrl + F or just go through logs. You can also add custom logs to your WCF service and find them in here to figure out where exactly your code is getting exception at, You can find more about Trace Viewer at, http://msdn.microsoft.com/en-us/library/aa751795(v=vs.110).aspx