Diagnostics of IExecutable/IQueryable before execution

[jbockle]

Having a filterable collection field with a resolver that returns IQueryable/IExecutable, shouldn't I be able to create an ExecutionDiagnosticEventListener so I can add a breakpoint/Print()/ToString() it for troubleshooting before it is executed? I don't know which method or which property on the context that would have the iexecutable with any queryable operations staged on it.

[PascalSenn]

This is not possible with an ExecutionDiagnosticEventListener as you are either to early or to late in the resolver pipeline. You either get nothing or the already executed result.

What you can do is you can add a middleware that prints this out:

public class Query
{
    [Report]
    [UseFiltering]
    public IExecutable<Customer> GetCustomers() => new[]
    {
        new Customer()
        {
            Id = 1
        },
        new Customer()
        {
            Id = 2
        }
    }.AsExecutable();
}

public class ReportAttribute : ObjectFieldDescriptorAttribute
{
    protected override void OnConfigure(
        IDescriptorContext context, IObjectFieldDescriptor descriptor, MemberInfo member)
    {
        descriptor.Use(next => async context =>
        {
            await next(context);
            if (context.Result is IExecutable executable)
            {
                Console.WriteLine(executable.Print());
            }
        });
    }
}