C# ASP.NET MVC RestAPI: Process headers before body and and parameters are received

The answer is yes, you can use the action filters. https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-3.1#action-filters

public class MySampleActionFilter : IActionFilter
{
    public void OnActionExecuting (ActionExecutingContext context)
    {
        // Do something before the action executes.
    }

    public void OnActionExecuted(ActionExecutedContext context)
    {
        // Do something after the action executes.
    }
}

As per documentation you can override the action context and short circuit the result, without going into the controller.

Result - setting Result short-circuits execution of the action method and subsequent action filters.

You can find your headers like this

var headers = context.HttpContext.Request.Headers;

// Ensure that all of your properties are present in the current Request
if(!String.IsNullOrEmpty(headers["version"])
{
     // All of those properties are available, handle accordingly

     // You can redirect your user based on the following line of code
     context.Result = new RedirectResult(url);
}
else
{
     // Those properties were not present in the header, redirect somewhere else
}