Limit the number of concurrent wcf sessions per user

Question

I have a WCF service that is session-based and secure (likely to use federated security).

I would like to allow only 1 concurrent session for each user. For example, bob can open a session and contact the server, but if it tries to open another session without closing the first, it will not succeed.

Does WCF support this out of the box? Thank!

Answer 1

I can’t figure out how to do this automatically. But you can do it manually by storing the list of sessions ( OperationContext.Current.Channel.SessionId) and associated users in memory in your service, perhaps like this:

private static Dictionary<string, Guid> activeSessions = new Dictionary<string, Guid>();

, , . , . , / . OperationContext.Current.Channel.OnClosed, , . , :

OperationContext.Current.Channel.OnClosed += (s, e) =>
    {
        Guid sessionId = ((IContextChannel)sender).SessionId;
        var entry = activeSessions.FirstOrDefault(kvp => kvp.Value == sessionId);
        activeSessions.Remove(entry.Key);
    };

Answer 2

, :

• , .
• , / .
• serviceAuthorization, .

. .

:

<system.serviceModel>
    <client>
        <endpoint name="NetTcpBinding_IService"
                  address="net.tcp://localhost:13031/Service"
                  binding="netTcpBinding" bindingConfiguration="TCP"
                  contract="Common.IService"/>
    </client>
    <bindings>
        <netTcpBinding>
            <binding name="TCP">
                <security mode="Transport">
                    <transport clientCredentialType="Windows" />
                </security>
            </binding>
        </netTcpBinding>
    </bindings>
</system.serviceModel>

:

<system.serviceModel>
    <services>
        <service name="Server.Service" behaviorConfiguration="customAuthorization">
            <endpoint address="net.tcp://localhost:13031/Service"
                      binding="netTcpBinding" bindingConfiguration="TCP"
                      contract="Common.IService" />
        </service>
    </services>
    <bindings>
        <netTcpBinding>
            <binding name="TCP">
                <security mode="Transport">
                    <transport clientCredentialType="Windows" />
                </security>
            </binding>
        </netTcpBinding>
    </bindings>
    <behaviors>
        <serviceBehaviors>
            <behavior name="customAuthorization">
                <serviceAuthorization 
                    serviceAuthorizationManagerType="Extensions.SingleSessionPerUserManager, Extensions"/>
            </behavior>
        </serviceBehaviors>
    </behaviors>
</system.serviceModel>

:

public class SingleSessionPerUserManager : ServiceAuthorizationManager
{
    private SessionStorage Storage { get; set; }

    public SingleSessionPerUserManager()
    {
        Storage = new SessionStorage();
    }

    protected override bool CheckAccessCore( OperationContext operationContext )
    {
        string name = operationContext.ServiceSecurityContext.PrimaryIdentity.Name;
        if ( Storage.IsActive( name ) )
            return false;

        Storage.Activate( operationContext.SessionId, name );
        operationContext.Channel.Closed += new EventHandler( Channel_Closed );
        return true;
    }

    private void Channel_Closed( object sender, EventArgs e )
    {
        Storage.Deactivate( ( sender as IContextChannel ).SessionId );
    }
}

, :

public class SessionStorage
{
    private Dictionary<string, string> Names { get; set; }

    public SessionStorage()
    {
        Names = new Dictionary<string, string>();
    }

    public void Activate( string sessionId, string name )
    {
        Names[ name ] = sessionId;
    }

    public void Deactivate( string sessionId )
    {
        string name = ( from n in Names where n.Value == sessionId select n.Key ).FirstOrDefault();
        if ( name == null )
            return;

        Names.Remove( name );
    }

    public bool IsActive( string name )
    {
        return Names.ContainsKey( name );
    }
}

: System.ServiceModel.Security.SecurityAccessDeniedException: ..