Question

I am writing a WCF web service which allows to register new users in system. So I have the following operation contract:

 [ServiceContract]
 public interface ISecurityService
 {
     /// <summary>
     /// Register new user in system, if no exceptions were thrown 
     /// user was registered successfully
     /// </summary>
     [OperationContract]
     [FaultContract(typeof(SecurityFaultException))]
     void Register(string userName, string password);
 }

The idea is simple how to synchronize Register method invocation to prevent registration of two users with the same names?

I thought about using IsolationLevel.Serializable but I’m not sure about this solution. Can somebody give me a good advice or share some good practice about WCF services synchronization.

UPDATED:
I save users in a database.

Answer 1

If you save users in db it’s enough to use default Isolationlevel(ReadCommited) an just put a unique constraint or primary key in UserName column that prevent duplicate value.