public void AddOrUpdate(EntityTagKey key, TimedEntityTagHeaderValue eTag)
{
_eTagCache.AddOrUpdate(key, eTag, (theKey, oldValue) => eTag);
_routePatternCache.AddOrUpdate(key.RoutePattern, new HashSet<EntityTagKey>() { key },
(routePattern, hashSet) =>
{
hashSet.Add(key);
return hashSet;
});
}
public static bool TryParse(string timedETagValue, out TimedEntityTagHeaderValue value)
{
value = null;
if (timedETagValue == null)
return false;
var strings = timedETagValue.Split(new[] { "\r\n" }, StringSplitOptions.None);
if (strings.Length != 2)
return false;
EntityTagHeaderValue etag = null;
DateTimeOffset lastModified;
if (!EntityTagHeaderValue.TryParse(strings[0], out etag))
return false;
if (!DateTimeOffset.TryParse(strings[1], out lastModified))
return false;
value = new TimedEntityTagHeaderValue(etag.Tag, etag.IsWeak)
{
LastModified = lastModified
};
return true;
}
/// <summary>
/// Adds caching for GET and PUT if
/// cache control provided is not null
/// With PUT, since cache has been alreay invalidated,
/// we provide the new ETag (old one has been cleared in invalidation phase)
/// </summary>
/// <param name="entityTagKey"></param>
/// <param name="request"></param>
/// <param name="response"></param>
/// <param name="varyHeaders"></param>
/// <returns></returns>
internal Action AddCaching(
EntityTagKey entityTagKey,
HttpRequestMessage request,
HttpResponseMessage response,
IEnumerable<KeyValuePair<string, IEnumerable<string>>> varyHeaders)
{
return
() =>
{
var cacheControlHeaderValue = CacheControlHeaderProvider(request);
if (cacheControlHeaderValue == null)
return;
TimedEntityTagHeaderValue eTagValue;
string uri = UriTrimmer(request.RequestUri);
// in case of GET and no ETag
// in case of PUT, we should return the new ETag of the resource
// NOTE: No need to check if it is in the cache. If it were, it would not get
// here
if (request.Method == HttpMethod.Get || request.Method == HttpMethod.Put)
{
// create new ETag only if it does not already exist
if (!_entityTagStore.TryGetValue(entityTagKey, out eTagValue))
{
eTagValue = new TimedEntityTagHeaderValue(ETagValueGenerator(uri, varyHeaders));
_entityTagStore.AddOrUpdate(entityTagKey, eTagValue);
}
// set ETag
response.Headers.ETag = eTagValue.ToEntityTagHeaderValue();
// set last-modified
if (AddLastModifiedHeader && response.Content != null && !response.Content.Headers.Any(x => x.Key.Equals(HttpHeaderNames.LastModified,
StringComparison.CurrentCultureIgnoreCase)))
{
response.Content.Headers.Add(HttpHeaderNames.LastModified, eTagValue.LastModified.ToString("r"));
}
// set Vary
if (AddVaryHeader && _varyByHeaders != null && _varyByHeaders.Length > 0)
{
response.Headers.Add(HttpHeaderNames.Vary, _varyByHeaders);
}
response.Headers.TryAddWithoutValidation(HttpHeaderNames.CacheControl, cacheControlHeaderValue.ToString());
}
};
}
public bool TryGetValue(EntityTagKey key, out TimedEntityTagHeaderValue eTag)
{
return _eTagCache.TryGetValue(key, out eTag);
}