protected virtual bool ResponseIsCacheable(ResultExecutedContext filterContext, CacheRouteConfig configuration) {
if (filterContext.HttpContext.Request.Url == null) {
return false;
}
// Don't cache non-200 responses or results of a redirect.
var response = filterContext.HttpContext.Response;
if (response.StatusCode != (int)HttpStatusCode.OK || _transformRedirect) {
return false;
}
// Don't cache in individual route configuration says no.
if (configuration != null && configuration.Duration == 0) {
Logger.Debug("Response for item '{0}' will not be cached because route is configured to not be cached.", _cacheKey);
return false;
}
// Don't cache if request created notifications.
var hasNotifications = !String.IsNullOrEmpty(Convert.ToString(filterContext.Controller.TempData["messages"]));
if (hasNotifications) {
Logger.Debug("Response for item '{0}' will not be cached because one or more notifications were created.", _cacheKey);
return false;
}
return true;
}
public void OnActionExecuting(ActionExecutingContext filterContext) {
Logger.Debug("Incoming request for URL '{0}'.", filterContext.RequestContext.HttpContext.Request.RawUrl);
// This filter is not reentrant (multiple executions within the same request are
// not supported) so child actions are ignored completely.
if (filterContext.IsChildAction) {
Logger.Debug("Action '{0}' ignored because it's a child action.", filterContext.ActionDescriptor.ActionName);
return;
}
_now = _clock.UtcNow;
_workContext = _workContextAccessor.GetContext();
var configurations = _cacheService.GetRouteConfigs();
if (configurations.Any()) {
var route = filterContext.Controller.ControllerContext.RouteData.Route;
var key = _cacheService.GetRouteDescriptorKey(filterContext.HttpContext, route);
_cacheRouteConfig = configurations.FirstOrDefault(c => c.RouteKey == key);
}
if (!RequestIsCacheable(filterContext))
return;
// Computing the cache key after we know that the request is cacheable means that we are only performing this calculation on requests that require it
_cacheKey = String.Intern(ComputeCacheKey(filterContext, GetCacheKeyParameters(filterContext)));
_invariantCacheKey = ComputeCacheKey(filterContext, null);
Logger.Debug("Cache key '{0}' was created.", _cacheKey);
try {
// Is there a cached item, and are we allowed to serve it?
var allowServeFromCache = filterContext.RequestContext.HttpContext.Request.Headers["Cache-Control"] != "no-cache" || CacheSettings.IgnoreNoCache;
var cacheItem = GetCacheItem(_cacheKey);
if (allowServeFromCache && cacheItem != null) {
Logger.Debug("Item '{0}' was found in cache.", _cacheKey);
// Is the cached item in its grace period?
if (cacheItem.IsInGracePeriod(_now)) {
// Render the content unless another request is already doing so.
if (Monitor.TryEnter(_cacheKey)) {
Logger.Debug("Item '{0}' is in grace period and not currently being rendered; rendering item...", _cacheKey);
BeginRenderItem(filterContext);
return;
}
}
// Cached item is not yet in its grace period, or is already being
// rendered by another request; serve it from cache.
Logger.Debug("Serving item '{0}' from cache.", _cacheKey);
ServeCachedItem(filterContext, cacheItem);
return;
}
// No cached item found, or client doesn't want it; acquire the cache key
// lock to render the item.
Logger.Debug("Item '{0}' was not found in cache or client refuses it. Acquiring cache key lock...", _cacheKey);
if (Monitor.TryEnter(_cacheKey)) {
Logger.Debug("Cache key lock for item '{0}' was acquired.", _cacheKey);
// Item might now have been rendered and cached by another request; if so serve it from cache.
if (allowServeFromCache) {
cacheItem = GetCacheItem(_cacheKey);
if (cacheItem != null) {
Logger.Debug("Item '{0}' was now found; releasing cache key lock and serving from cache.", _cacheKey);
Monitor.Exit(_cacheKey);
ServeCachedItem(filterContext, cacheItem);
return;
}
}
}
// Either we acquired the cache key lock and the item was still not in cache, or
// the lock acquisition timed out. In either case render the item.
Logger.Debug("Rendering item '{0}'...", _cacheKey);
BeginRenderItem(filterContext);
}
catch {
// Remember to release the cache key lock in the event of an exception!
Logger.Debug("Exception occurred for item '{0}'; releasing any acquired lock.", _cacheKey);
ReleaseCacheKeyLock();
throw;
}
}
