ajax with WCF work. but few miniute after, doesn't work.

Question

I am a new to WCF. I have written ajax to use a web service before, but on this project I am trying to use ajax to WCF.

After I build the project and wcf using ajax, I receive the return successfully. But, 10 or more minutes later I don't get a return, the ajax calls the error function, and the fiddler returns nothing.

If I rebuild the project without any source modifying, I receive the return successfully again.

Is their anybody who has experienced this or knows why this might be?

Thank You.

Answer 1

Most likely you're not closing the connections. You should wrap all your calls in Try/Catch/Finally blocks.

In C#:

ServiceClient service = GetService();

        try
        {
            SomeRequest request = new SomeRequest();

            SomeResponse response = service.GetSome(request);

            return response.Result;
        }
        catch (Exception ex)
        {
            // do some error handling
        }
        finally
        {
            try
            {
                if (service.State != CommunicationState.Faulted)
                {
                    service.Close();
                }
            }
            catch (Exception ex)
            {
                service.Abort();
            }
        }

or VB

        Dim service As ServiceClient = GetService()

        Try
            Dim request As New SomeRequest()

            Dim response As SomeResponse = service.GetSome(request)

            Return response.Result
        Catch ex As Exception
            ' do some error handling
        Finally
            Try
                If service.State <> CommunicationState.Faulted Then
                    service.Close()
                End If
            Catch ex As Exception
                service.Abort()
            End Try
        End Try

Answer 2

Here is the best practice for calling WCF services:

    public static void CallService<T>(Action<T> action) where T 
           : class, ICommunicationObject, new()
    {
        var client = new T();

        try
        {
            action(client);
            client.Close();
        }
        finally
        {
            if (client.State == CommunicationState.Opened)
            {
                try
                {
                    client.Close();
                }
                catch (CommunicationObjectFaultedException)
                {
                    client.Abort();
                }
                catch (TimeoutException)
                {
                    client.Abort();
                }
            }
            if (client.State != CommunicationState.Closed)
            {
                client.Abort();
            }
        }
    }

Each WCF call should create a new instance of your service class. This code allows you to enforce that and just call the services like this:

CallService<MyService>( t => t.CallMyService());