Refresh Schema Explorer programmatically from dynamic driver

ronnieoverby

I'm creating a dynamic driver. I would like to allow the users of the driver to configure the driver via an API embedded in the driver and when they have, I want to programmatically kick off a schema explorer refresh.

I've read about overriding GetLastSchemaUpdate which will react to "old fashioned" SQL statements, but this doesn't suit my needs.

Is there a way?

JoeAlbahari

There's no way to do this, and it's a reasonable request.

Would it help if I added the following method to IConnectionInfo?

Task ForceRefresh();

The obvious place to call this would be in the OnQueryFinishing method of your DataContextDriver. However, you could call it earlier if you cached the IConnectionInfo:

static IConnectionInfo _currentCxInfo;    
public override void InitializeContext (IConnectionInfo cxInfo, object context, ...)
{
    _currentCxInfo = cxInfo;
}

Would this work for you?

ronnieoverby

I believe that would do the trick. Thanks!

JoeAlbahari

This feature is now supported in the latest beta (6.9.2). Note that for now, you will need to reference the latest preview package of LINQPad.Reference (1.2.0-beta) in your driver project.

Let me know how you get along.

ronnieoverby

Thanks, joe. I'll test shortly.

ronnieoverby

This works well for me:

public override void OnQueryFinishing(IConnectionInfo cxInfo, object context, QueryExecutionManager executionManager)
{    
#if NETCORE
    dynamic dontext = context;
    if (dontext.RefreshConnection)
        cxInfo.ForceRefresh();
#endif

    base.OnQueryFinishing(cxInfo, context, executionManager);
}

I noticed that the reference assembly for LINQPad 5 did not include the new method. Will cxInfo.ForceRefresh() be available in v5?

ronnieoverby

I wanted to handle the absence of ForceRefresh() gracefully, like this:

void RefreshConnectionIfNeeded(dynamic context, dynamic cxInfo)
{
    // using dynamic for the context
    // because it's generated at runtime

    // using dynamic for the cxInfo instance
    // because ForceRefresh() is new and older
    // version of linqpad won't have the method

    if (context.RefreshConnection)
    {
        try
        {
            cxInfo.ForceRefresh();
        }
        catch (RuntimeBinderException)
        {
            "Refresh the connection to apply changes.".Dump();
        }
    }
}

This won't work because ForceRefresh() is a default interface implementation. Apparently the DLR cannot dispatch to those.

ronnieoverby

Looks like reflection will work for me.

JoeAlbahari

You could do this:

void RefreshConnection (IConnectionInfo cxInfo)
{
    if (this.LINQPadVersion >= new Version (6, 9, 2)) ForceRefresh (cxInfo);
}

static void ForceRefresh (IConnectionInfo cxInfo)
{
#if NETCORE
    cxInfo.ForceRefresh ();
#endif
}