protected async Task <BackendResponse> GetFromCacheThenFromBackendAsync(
string format,
IRestClient restClient,
Func <IRestRequest> createBackendRequestFunc,
string cacheKey,
RequestHeaders requestHeaders,
Action <HttpStatusCode> handleNotOkResponseAction,
CancellationToken cancellationToken)
{
var acceptType = requestHeaders.DetermineAcceptType(format);
if (_redis != null)
{
var key = $"{cacheKey}.{acceptType.ToString()}".ToLowerInvariant();
try
{
var db = _redis.GetDatabase();
var cachedValues =
await db.HashGetAllAsync(
key,
CommandFlags.PreferSlave);
if (cachedValues.Length > 0)
{
var cachedValue = cachedValues.FirstOrDefault(x => x.Name.Equals(ValueKey));
var cachedHeaders = cachedValues.FirstOrDefault(x => x.Name.Equals(HeadersKey));
var cachedLastModified = cachedValues.FirstOrDefault(x => x.Name.Equals(LastModifiedKey));
var headers = JsonConvert.DeserializeObject <Dictionary <string, string[]> >(cachedHeaders.Value);
headers.TryGetValue(AddVersionHeaderMiddleware.HeaderName, out var downstreamVersion);
return(new BackendResponse(
cachedValue.Value,
downstreamVersion?.First(),
DateTimeOffset.ParseExact(
cachedLastModified.Value,
"O",
CultureInfo.InvariantCulture),
acceptType.ToMimeTypeString(),
true));
}
_logger.LogError("Failed to retrieve record {Record} from Redis, no cached values.", key);
}
catch (Exception ex)
{
_logger.LogError(ex, "Failed to retrieve record {Record} from Redis.", key);
}
}
return(await GetFromBackendAsync(
restClient,
createBackendRequestFunc,
acceptType,
handleNotOkResponseAction,
cancellationToken));
}
protected async Task <BackendResponse> GetFromBackendWithBadRequestAsync(
string format,
Func <IRestRequest> createBackendRequestFunc,
RequestHeaders requestHeaders,
Action <HttpStatusCode> handleNotOkResponseAction,
CancellationToken cancellationToken)
=> await GetFromBackendWithBadRequestAsync(
_restClient,
createBackendRequestFunc,
requestHeaders.DetermineAcceptType(format),
handleNotOkResponseAction,
cancellationToken);