Using Enterpise Library 6 Exception Handling Application Block with WCF? - wcf

Question

I have these three packages loaded to my WCF service project:
EnterpriseLibrary.Common Version 6.0.1304.0
EnterpriseLibrary.ExceptionHandling 6.0.1304.0
EnterpriseLibrary.ExceptionHandling.WCF Version 6.0.1304.0
Here is the service interface and MyTestFault DataContract:
[ServiceContract]
public interface IRepairService
{
[OperationContract]
[FaultContract(typeof(MyTestFault))]
string SaveRepairCode(string failureCode, string description);
}
[DataContract]
public class MyTestFault
{
#region Member Fields
private string _message = "An unexpected error occured while executing the service method.";
#endregion
#region Properties
[DataMember]
public string Message
{
get { return _message; }
set { _message = value; }
}
#endregion
#region Constructor(s)
public MyTestFault() { }
#endregion
}
Here is the implementation of the service:
[ExceptionShielding("TestPolicy")]
public class RepairService : IRepairService
{
#region Private members
private WimDAL wimDAL;
ExceptionManager exManager;
#endregion
#region Constructor(s)
public RepairService()
{
wimDAL = new WimDAL();
var testPolicy = new List<ExceptionPolicyEntry>
{
{
new ExceptionPolicyEntry(
typeof(SqlException),
PostHandlingAction.ThrowNewException,
new IExceptionHandler[]
{
new FaultContractExceptionHandler(
typeof(MyTestFault),
"SqlException Occurred.",
new NameValueCollection(){ { "Message", "Message" }})
})
},
{
new ExceptionPolicyEntry(
typeof(Exception),
PostHandlingAction.ThrowNewException,
new IExceptionHandler[]
{
new FaultContractExceptionHandler(
typeof(MyTestFault),
"Exception Occurred.",
new NameValueCollection(){ { "Message", "Message" }})
})
}
};
var policies = new List<ExceptionPolicyDefinition>();
policies.Add(new ExceptionPolicyDefinition(
"TestPolicy", testPolicy));
exManager = new ExceptionManager(policies);
}
#endregion
/// <summary>
/// Insert a new fail code with description into RPCODE.
/// Duplicate primary key will throw SqlException that should be processed by EHAB
/// </summary>
public string SaveRepairCode(string failureCode, string description)
{
using (TransactionScope txScope = new TransactionScope())
{
WimSQLCommand sc = new WimSQLCommand() { StoredProcedure = "Repair.RPCODE_Insert" };
sc.Parameters.Add(new SqlParameter("#FailureCode", failureCode));
sc.Parameters.Add(new SqlParameter("#Desc", description));
exManager.Process(() => wimDAL.Execute_NonQueryNoReturn(sc), "TestPolicy");
txScope.Complete();
return "<Save_Repair_Code></Save_Repair_Code>";
}
}
}
Now, I have a TestClient console application that is part of the same project that has a reference to the project and a service reference. From there I call the SaveRepairCode() method and try to catch the specific fault exception like so:
ServiceReference1.RepairServiceClient r = new ServiceReference1.RepairServiceClient();
Console.WriteLine("Enter a new repair code:");
string repairCode = Console.ReadLine();
Console.WriteLine("Enter description:");
string description = Console.ReadLine();
try
{
r.SaveRepairCode(repairCode, description);
}
catch (FaultException<MyTestFault> ex)
{
//do something
throw;
}
catch (FaultException fex)
{
//do something
throw;
}
Finally, I run the console app and try to save a duplicate repair code. I know through debugging that this causes the SqlException to occur. After I step over the SqlException, I see the "FaultContractWrapperException was unhandled by user code" exception and it has the message I specified in the policy of "SqlException occurred.". When I step over that I get back to the client and see this error:
CommunicationException was unhandled
The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error.
PS - this is Enterprise Library 6 with WCF and I made no manual changes to the web.config... and yes, includeExceptionDetailInFaults is set to false.
What am I missing here? Thanks in advance.
UPDATE
Looks like I was missing this one line of code after instantiating the new ExceptionManager.
ExceptionPolicy.SetExceptionManager(exManager);
Nice to see that this one line of code is NOT in the Enterprise Library 6 - April 2013.chm but it IS in the "Developer's Guide to Microsoft Enterprise Library-Preview.pdf" on page 90 of 269. After including that one line I get into the proper FaultException catch on the client.
With that being said, I still can't get other MyTestFault properties on the client. For example, if I add public string StoredProcedureName to MyTestFault and map it to the SqlException's "Procedure" property, I always see null on the client. The only change in the policy for this would be to add the mapping like so:
new NameValueCollection(){ { "Message", "{Message}" }, { "StoredProcedureName", "{Procedure}" } }

Answer 1

It turns out this line was the culprit.
exManager.Process(() => wimDAL.Execute_NonQueryNoReturn(sc), "TestPolicy");
Insead of using the ExceptionManager's Process method, just execute the command you expect a potential exception for like so.
wimDAL.Execute_NonQueryNoReturn(sc);
This does not follow what the "Developer's Guide to Microsoft Enterprise Library-Preview.pdf" says but I guess the documentation is still a work in progress. I hope this helps someone else.