public async Task SetAsync(
RedisKey key,
string response,
int responseStatusCode,
Dictionary <string, string[]> headers)
{
var storeKey = new StoreKey {
{ "key", key }
};
var etag = await _eTagGenerator.GenerateETag(storeKey, response);
var hashFields = new[]
{
new HashEntry(ETagKey, etag.Value),
new HashEntry(ETagTypeKey, etag.ETagType.ToString()),
new HashEntry(LastModifiedKey, DateTime.Now.ToString("O", CultureInfo.InvariantCulture)),
new HashEntry(SetByRegistryKey, true.ToString(CultureInfo.InvariantCulture)),
new HashEntry(ValueKey, response),
new HashEntry(HeadersKey, JsonConvert.SerializeObject(headers)),
new HashEntry(ResponseStatusCodeKey, responseStatusCode)
};
if (_batch == null)
{
var db = _redis.GetDatabase();
await db.HashSetAsync(key, hashFields, CommandFlags.FireAndForget);
}
else
{
await _batch.HashSetAsync(key, hashFields, CommandFlags.FireAndForget);
}
}
private async Task GenerateValidationHeadersOnResponse(HttpContext httpContext)
{
// don't generate these for 304 - that's taken care of at the
// start of the request
if (httpContext.Response.StatusCode == StatusCodes.Status304NotModified)
{
return;
}
// This takes care of storing new tags, also after a succesful PUT/POST/PATCH.
// Other PUT/POST/PATCH requests must thus include the new ETag as If-Match,
// otherwise the precondition will fail.
//
// If an API returns a 204 No Content after PUT/PATCH, the ETag will be generated
// from an empty response - any other user/cache must GET the response again
// before updating it. Getting it will result in a new ETag value being generated.
//
// If an API returns a 200 Ok after PUT/PATCH, the ETag will be generated from
// that response body - if the update was succesful but nothing was changed,
// in those cases the original ETag for other users/caches will still be sufficient.
// if the response body cannot be read, we can never
// generate correct ETags (and it should never be cached)
if (!httpContext.Response.Body.CanRead)
{
return;
}
_logger.LogInformation("Generating Validation headers.");
var headers = httpContext.Response.Headers;
// remove any other ETag and Last-Modified headers (could be set by other pieces of code)
headers.Remove(HeaderNames.ETag);
headers.Remove(HeaderNames.LastModified);
// get the request key
var storeKey = await _storeKeyGenerator.GenerateStoreKey(
ConstructStoreKeyContext(httpContext.Request, _validationModelOptions));
// get the response bytes
if (httpContext.Response.Body.CanSeek)
{
httpContext.Response.Body.Position = 0;
}
var responseBodyContent = new StreamReader(httpContext.Response.Body).ReadToEnd();
// Calculate the ETag to store in the store.
var eTag = await _eTagGenerator.GenerateETag(storeKey, responseBodyContent);
var lastModified = await _lastModifiedInjector.CalculateLastModified(
new ResourceContext(httpContext.Request, storeKey));
var lastModifiedValue = await _dateParser.LastModifiedToString(lastModified);
// store the ETag & LastModified date with the request key as key in the ETag store
await _store.SetAsync(storeKey, new ValidatorValue(eTag, lastModified));
// set the ETag and LastModified header
headers[HeaderNames.ETag] = eTag.ToString();
headers[HeaderNames.LastModified] = lastModifiedValue;
_logger.LogInformation($"Validation headers generated. ETag: {eTag.ETagType}, {eTag}. Last-Modified: {lastModifiedValue}");
}
private async Task GenerateETagHeaderAsync(HttpContext context)
{
context.Response.GetTypedHeaders().ETag = await _eTagGenerator.GenerateETag(context);
}