public PrivateCacheHandler(HttpMessageHandler innerHandler, HttpCache httpCache)
{
_httpCache = httpCache;
InnerHandler = innerHandler;
}
public PrivateCacheHandler(HttpMessageHandler innerHandler, HttpCache httpCache)
{
_httpCache = httpCache;
InnerHandler = innerHandler;
}
public async Task <CacheQueryResult> QueryCacheAsync(HttpRequestMessage request)
{
// Do we have anything stored for this method and URI?
var cacheEntry = await _contentStore.GetEntryAsync(new PrimaryCacheKey(request.RequestUri, request.Method));
if (cacheEntry == null)
{
return(CacheQueryResult.CannotUseCache());
}
// Do we have a matching variant representation?
var secondaryKey = cacheEntry.CreateSecondaryKey(request); //, cacheEntry.VaryHeaders
if (secondaryKey == "*") // Vary: * never matches
{
return(CacheQueryResult.CannotUseCache());
}
var selectedResponse = await _contentStore.GetContentAsync(cacheEntry, secondaryKey);
if (selectedResponse == null)
{
return(CacheQueryResult.CannotUseCache());
}
// Do caching directives require that we revalidate it regardless of freshness?
var requestCacheControl = request.Headers.CacheControl ?? new CacheControlHeaderValue();
if ((requestCacheControl.NoCache || selectedResponse.CacheControl.NoCache))
{
return(CacheQueryResult.Revalidate(selectedResponse));
}
// Is it fresh?
if (selectedResponse.IsFresh())
{
if (requestCacheControl.MinFresh != null)
{
if (HttpCache.CalculateAge(selectedResponse.Response) <= requestCacheControl.MinFresh)
{
return(CacheQueryResult.ReturnStored(selectedResponse));
}
}
else
{
return(CacheQueryResult.ReturnStored(selectedResponse));
}
}
// Did the client say we can serve it stale?
if (requestCacheControl.MaxStale)
{
if (requestCacheControl.MaxStaleLimit != null)
{
if ((DateTime.UtcNow - selectedResponse.Expires) <= requestCacheControl.MaxStaleLimit)
{
return(CacheQueryResult.ReturnStored(selectedResponse));
}
}
else
{
return(CacheQueryResult.ReturnStored(selectedResponse));
}
}
// Do we have a selector to allow us to do a conditional request to revalidate it?
if (selectedResponse.HasValidator)
{
return(CacheQueryResult.Revalidate(selectedResponse));
}
// Can't do anything to help
return(CacheQueryResult.CannotUseCache());
}
