private static void CalculateETagAndCopyStreamIfNecessary(HttpResponse resp, HttpRequest req, MemoryStream buffer, Stream stream)
{
using (var reader = new StreamReader(buffer))
{
if (resp.Headers[HeaderNames.ETag].Count == 0)
{
var body = reader.ReadToEnd();
resp.Headers.Add(HeaderNames.ETag, ETagGenerator.GetETag(req, body));
if (req.Headers[HeaderNames.IfNoneMatch].Count != 0 && req.Headers[HeaderNames.IfNoneMatch] == resp.Headers[HeaderNames.ETag])
{
resp.StatusCode = StatusCodes.Status304NotModified; // this will blank response
}
}
CopyStreamIfNecessary(resp, buffer, stream);
}
}
public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
var executedContext = await next.Invoke();
var req = executedContext.HttpContext.Request;
var resp = executedContext.HttpContext.Response;
if (!ValidateMethod(req, resp) || executedContext.Result == null)
{
return;
}
var eTag = ETagGenerator.GetETag(executedContext.HttpContext.Request, JsonConvert.SerializeObject(executedContext.Result));
SetCacheHeaderForClientSideCaching(resp, eTag);
if (CacheLocation == CacheLocation.Client)
{
return;
}
await CacheService.Store($"{_cacheKey}_{HeaderNames.ETag}", eTag, ServerSideDuration);
}