Return Cache-Control response header in a Web API response

CacheFilterAttribtue.cs

public class CacheFilterAttribute : ActionFilterAttribute
{
    int DurationInSeconds = int.Parse(ConfigurationManager.AppSettings["CacheDuration"]);

    public override Task OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, CancellationToken cancellationToken)
    {
        if (actionExecutedContext.Request.Method == HttpMethod.Get)
        {
            actionExecutedContext.Response.Headers.CacheControl = new CacheControlHeaderValue()
            {
                MaxAge = TimeSpan.FromSeconds(DurationInSeconds),
                Public = true
            };
        }

        return Task.FromResult(0);
    }
}