/// <summary>
/// Finalize cache headers.
/// </summary>
/// <param name="context"></param>
/// <returns><c>true</c> if a vary by entry needs to be stored in the cache; otherwise <c>false</c>.</returns>
private bool OnFinalizeCacheHeaders(ResponseCachingContext context)
{
if (_policyProvider.IsResponseCacheable(context))
{
var storeVaryByEntry = false;
context.ShouldCacheResponse = true;
// Create the cache entry now
var response = context.HttpContext.Response;
var headers = response.Headers;
var varyHeaders = new StringValues(headers.GetCommaSeparatedValues(HeaderNames.Vary));
var varyQueryKeys = new StringValues(context.HttpContext.Features.Get <IResponseCachingFeature>()?.VaryByQueryKeys);
context.CachedResponseValidFor = context.ResponseSharedMaxAge ??
context.ResponseMaxAge ??
(context.ResponseExpires - context.ResponseTime !.Value) ??
DefaultExpirationTimeSpan;
// Generate a base key if none exist
if (string.IsNullOrEmpty(context.BaseKey))
{
context.BaseKey = _keyProvider.CreateBaseKey(context);
}
// Check if any vary rules exist
if (!StringValues.IsNullOrEmpty(varyHeaders) || !StringValues.IsNullOrEmpty(varyQueryKeys))
{
// Normalize order and casing of vary by rules
var normalizedVaryHeaders = GetOrderCasingNormalizedStringValues(varyHeaders);
var normalizedVaryQueryKeys = GetOrderCasingNormalizedStringValues(varyQueryKeys);
// Update vary rules if they are different
if (context.CachedVaryByRules == null ||
!StringValues.Equals(context.CachedVaryByRules.QueryKeys, normalizedVaryQueryKeys) ||
!StringValues.Equals(context.CachedVaryByRules.Headers, normalizedVaryHeaders))
{
context.CachedVaryByRules = new CachedVaryByRules
{
VaryByKeyPrefix = FastGuid.NewGuid().IdString,
Headers = normalizedVaryHeaders,
QueryKeys = normalizedVaryQueryKeys
};
}
// Always overwrite the CachedVaryByRules to update the expiry information
_logger.VaryByRulesUpdated(normalizedVaryHeaders, normalizedVaryQueryKeys);
storeVaryByEntry = true;
context.StorageVaryKey = _keyProvider.CreateStorageVaryByKey(context);
}
// Ensure date header is set
if (!context.ResponseDate.HasValue)
{
context.ResponseDate = context.ResponseTime !.Value;
// Setting the date on the raw response headers.
headers.Date = HeaderUtilities.FormatDate(context.ResponseDate.Value);
}
// Store the response on the state
context.CachedResponse = new CachedResponse
{
Created = context.ResponseDate.Value,
StatusCode = response.StatusCode,
Headers = new HeaderDictionary()
};
foreach (var header in headers)
{
if (!string.Equals(header.Key, HeaderNames.Age, StringComparison.OrdinalIgnoreCase))
{
context.CachedResponse.Headers[header.Key] = header.Value;
}
}
return(storeVaryByEntry);
}
context.ResponseCachingStream.DisableBuffering();
return(false);
}
