private Func <IInvocation, Task> CreateMethod(MethodInfo method)
{
var returnType = method.ReturnType;
if (!typeof(Task).IsAssignableFrom(returnType))
{
throw new InvalidOperationException($"Hub invocation method `{method.Name}` must return a Task");
}
if (returnType == typeof(Task))
{
return(inv => connection.SendAsync(method.Name, inv.Arguments));
}
else if (returnType.GetGenericTypeDefinition() == typeof(Task <>))
{
var actualReturnType = returnType.GetGenericArguments().Single();
var castMethod = TaskCastMethod.MakeGenericMethod(new[] { actualReturnType });
return(inv =>
{
var res = connection.InvokeAsync(method.Name, inv.Arguments, actualReturnType);
return (Task)castMethod.Invoke(null, new[] { res });
});
}
throw new InvalidOperationException($"Task is assignable from {returnType}, but is not a Task, nor Task<>, should never happen");
}