private void Generate412PreconditionFailedResponse(HttpContext httpContext)
{
var headers = httpContext.Response.Headers;
httpContext.Response.StatusCode = StatusCodes.Status412PreconditionFailed;
// set the ETag & Last-Modified date.
// remove any other ETag and Last-Modified headers (could be set
// by other pieces of code)
headers.Remove(HeaderNames.ETag);
headers.Remove(HeaderNames.LastModified);
// generate key, ETag and LastModified
var requestKey = GenerateRequestKey(httpContext.Request);
// strong eTags by default!
var eTag = new ETag(ETagType.Strong, httpContext.Request.Headers[HeaderNames.IfNoneMatch].ToString());
var lastModified = DateTimeOffset.UtcNow;
// store (overwrite)
_store.SetAsync(requestKey, new ValidationValue(eTag, lastModified));
// set headers
headers[HeaderNames.ETag] = eTag.Value;
headers[HeaderNames.LastModified] = lastModified.ToString("r", CultureInfo.InvariantCulture);
}
private async Task GenerateResponseFromStore(HttpContext httpContext)
{
var headers = httpContext.Response.Headers;
// set the ETag & Last-Modified date.
// remove any other ETag and Last-Modified headers (could be set
// by other pieces of code)
headers.Remove(HeaderNames.ETag);
headers.Remove(HeaderNames.LastModified);
// generate key
var requestKey = GenerateRequestKey(httpContext.Request);
// set LastModified
// r = RFC1123 pattern (https://msdn.microsoft.com/en-us/library/az4se3k1(v=vs.110).aspx)
var lastModified = GetUtcNowWithoutMilliseconds();
headers[HeaderNames.LastModified] = lastModified.ToString("r", CultureInfo.InvariantCulture);
ETag eTag = null;
// take ETag value from the store (if it's found)
var savedResponse = await _store.GetAsync(requestKey);
if (savedResponse?.ETag != null)
{
eTag = new ETag(savedResponse.ETag.ETagType, savedResponse.ETag.Value);
headers[HeaderNames.ETag] = savedResponse.ETag.Value;
}
// store (overwrite)
await _store.SetAsync(requestKey, new ValidationValue(eTag, lastModified));
var logInformation = string.Empty;
if (eTag != null)
{
logInformation = $"ETag: {eTag.ETagType.ToString()}, {eTag.Value}, ";
}
logInformation += $"Last-Modified: {lastModified.ToString("r", CultureInfo.InvariantCulture)}.";
_logger.LogInformation($"Generation done. {logInformation}");
}