private async Task <bool> CheckIfUnmodifiedSinceIsValid(HttpContext httpContext, ValidatorValue validatorValue)
{
// Either the ETag matches (or one of them), or there was no IfMatch header.
// Continue with checking the IfUnModifiedSince header, if it exists.
if (httpContext.Request.Headers.Keys.Contains(HeaderNames.IfUnmodifiedSince))
{
// if the LastModified date is smaller than the IfUnmodifiedSince date,
// the precondition is valid.
var ifUnmodifiedSinceValue = httpContext.Request.Headers[HeaderNames.IfUnmodifiedSince].ToString();
_logger.LogInformation($"Checking If-Unmodified-Since: {ifUnmodifiedSinceValue}");
var parsedIfUnmodifiedSince = await _dateParser.IfUnmodifiedSinceToDateTimeOffset(ifUnmodifiedSinceValue);
if (parsedIfUnmodifiedSince.HasValue)
{
// If the LastModified date is smaller than the IfUnmodifiedSince date,
// the precondition is valid.
return(validatorValue.LastModified.CompareTo(parsedIfUnmodifiedSince.Value) < 0);
}
// can only check if we can parse it. Invalid values must be ignored.
_logger.LogInformation("Cannot parse If-Unmodified-Since value as date, header is ignored.");
return(true);
}
// if there is no IfUnmodifiedSince header, the check is valid.
_logger.LogInformation("No If-Unmodified-Since header.");
return(true);
}
private async Task <bool> CheckIfModifiedSinceIsValid(HttpContext httpContext, ValidatorValue validatorValue)
{
if (httpContext.Request.Headers.Keys.Contains(HeaderNames.IfModifiedSince))
{
// if the LastModified date is smaller than the IfModifiedSince date,
// we can return a 304 Not Modified (If there's also a matching ETag).
// By adding an If-Modified-Since date
// to a GET/HEAD request, the consumer is stating that (s)he only wants the resource
// to be returned if if has been modified after that.
var ifModifiedSinceValue = httpContext.Request.Headers[HeaderNames.IfModifiedSince].ToString();
_logger.LogInformation($"Checking If-Modified-Since: {ifModifiedSinceValue}");
var parsedIfModifiedSince = await _dateParser.IfModifiedSinceToDateTimeOffset(ifModifiedSinceValue);
if (parsedIfModifiedSince.HasValue)
{
return(validatorValue.LastModified.CompareTo(parsedIfModifiedSince.Value) <= 0);
}
// can only check if we can parse it. Invalid values must be ignored.
_logger.LogInformation("Cannot parse If-Modified-Since value as date, header is ignored.");
return(true);
}
// if there is no IfModifiedSince header, the check is valid.
_logger.LogInformation("No If-Modified-Since header.");
return(true);
}
