public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var httpContext = filterContext.HttpContext;
var requestIdentity = CacheViewIdentity.Create(httpContext.Request.Headers["If-None-Match"]);
filterContext.Controller.ViewBag.CacheViewIdentity = requestIdentity;
if (NotModified(requestIdentity, httpContext.Cache, out var modifiedCacheView))
{
filterContext.Result = new HttpStatusCodeResult(HttpStatusCode.NotModified).SetCacheHeader(
httpContext.Response,
$"{requestIdentity.CacheKey}-{requestIdentity.Checksum}");
return;
}
if (modifiedCacheView != null)
{
filterContext.Result =
new ContentResult {
Content = modifiedCacheView.Output, ContentType = "text/html"
}.SetCacheHeader(
httpContext.Response,
$"{requestIdentity.CacheKey}-{modifiedCacheView.Checksum}");
return;
}
base.OnActionExecuting(filterContext);
}
private static bool NotModified(CacheViewIdentity identity, Cache container, out CacheView modifiedCacheView)
{
modifiedCacheView = null;
if (identity == null)
{
return(false);
}
var cacheView = container[identity.CacheKey] as CacheView;
if (cacheView == null)
{
return(false);
}
if (identity.Checksum.Equals(cacheView.Checksum))
{
return(true);
}
modifiedCacheView = cacheView;
return(false);
}
