internal Func <HttpRequestMessage, Task <HttpResponseMessage> > GetIfMatchNoneMatch()
{
return((request) =>
{
if (request.Method != HttpMethod.Get)
{
return null;
}
ICollection <EntityTagHeaderValue> noneMatchTags = request.Headers.IfNoneMatch;
ICollection <EntityTagHeaderValue> matchTags = request.Headers.IfMatch;
if (matchTags.Count == 0 && noneMatchTags.Count == 0)
{
return null; // no etag
}
if (matchTags.Count > 0 && noneMatchTags.Count > 0) // both if-match and if-none-match exist
{
return new HttpResponseMessage(HttpStatusCode.BadRequest).ToTask();
}
var isNoneMatch = noneMatchTags.Count > 0;
var etags = isNoneMatch ? noneMatchTags : matchTags;
var resource = UriTrimmer(request.RequestUri);
var headers =
request.Headers.Where(h => _varyByHeaders.Any(v => v.Equals(h.Key, StringComparison.CurrentCultureIgnoreCase)));
var entityTagKey = EntityTagKeyGenerator(resource, headers);
// compare the Etag with the one in the cache
// do conditional get.
TimedEntityTagHeaderValue actualEtag = null;
bool matchFound = false;
if (_entityTagStore.TryGetValue(entityTagKey, out actualEtag))
{
if (etags.Any(etag => etag.Tag == actualEtag.Tag))
{
matchFound = true;
}
}
return matchFound ^ isNoneMatch ? null : new NotModifiedResponse(actualEtag.ToEntityTagHeaderValue()).ToTask();
});
}
internal Func <HttpRequestMessage, Task <HttpResponseMessage> > GetIfModifiedUnmodifiedSince()
{
return((request) =>
{
if (request.Method != HttpMethod.Get && request.Headers != null)
{
return null;
}
DateTimeOffset?ifModifiedSince = request.Headers.IfModifiedSince;
DateTimeOffset?ifUnmodifiedSince = request.Headers.IfUnmodifiedSince;
if (ifModifiedSince == null && ifUnmodifiedSince == null)
{
return null; // no etag
}
if (ifModifiedSince != null && ifUnmodifiedSince != null) // both exist
{
return new HttpResponseMessage(HttpStatusCode.BadRequest).ToTask();
}
bool ifModified = (ifUnmodifiedSince == null);
DateTimeOffset modifiedInQuestion = ifModified ? ifModifiedSince.Value : ifUnmodifiedSince.Value;
var headers =
request.Headers.Where(h => _varyByHeaders.Any(v => v.Equals(h.Key, StringComparison.CurrentCultureIgnoreCase)));
var resource = UriTrimmer(request.RequestUri);
var entityTagKey = EntityTagKeyGenerator(resource, headers);
TimedEntityTagHeaderValue actualEtag = null;
bool isModified = false;
if (_entityTagStore.TryGetValue(entityTagKey, out actualEtag))
{
isModified = actualEtag.LastModified > modifiedInQuestion;
}
return isModified ^ ifModified
? new NotModifiedResponse(actualEtag.ToEntityTagHeaderValue()).ToTask()
: null;
});
}
