How to get a Custom Attribute value of WCF Contract's Operation using IDispatchMessageInspector

Question

The question is in AfterReceiveRequest how to find out the custom attribute set on the Operation using the OperationDescription? If there's a way, is it better to set the custom attribute on operation declaration in service contract interface or the service implementation class?

To illustrate the question further:

public interface IGetterSetterService
{
    [OperationContract, GetterRequest]
    Data[] GetData();
    [OperationContract, SetterRequest]
    bool SetData(string Data);
}

OR

[WebInvoke(Method = "*", ResponseFormat = WebMessageFormat.Json, UriTemplate = "xyz"]
[GetterRequest]
public Data[] GetData()
{
    return new Data[];
}
[WebInvoke(Method = "*", ResponseFormat = WebMessageformat.Json, UriTemplate = "xyz/{data}"]
[SetterRequest]
public bool SetData(string data)
{
    return true;
}

Now the IDispatchMessageInspector:

public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
{
    //Here how to find out the GetterRequest or SetterRequest custom attribute set on an
    //operation, may be using OperationDescription for the current context?
}

Answer 1

My complete solution looks like this and it works without any problem:
1. First get the operation description as discussed here
2. Then find the custom attributes set on Operations in Service interface:

private UserAction GetIntendedUserAction(OperationDescription opDesc)
{
    Type contractType = opDesc.DeclaringContract.ContractType;
    var attr = contractType.GetMethod(opDesc.Name).GeCustomAttributes(typeof(RequestedAction), false) as RequestedAction[];
    if (attr != null && attr.Length > 0)
    {
        return attr[0].ActionName;
    }
    else
    {
        return UserAction.Unknown;
    }
}
public enum UserAction
{
    Unknown = 0,
    View = 1,
    Control = 2,
    SysAdmin = 3,
}
[AttributeUsage(AttributeTargets.Method)]
public class RequestedAction : Attribute
{
    public UserAction ActionName { get; set; }
    public RequestedAction(UserAction action)
    {
        ActionName = action;
    }
}