Upstream: fixed X-Accel-Expires/Cache-Control/Expires handling.
Previously, if caching was disabled due to Expires in the past, nginx
failed to cache the response even if it was cacheable as per subsequently
parsed Cache-Control header (ticket #964).
Similarly, if caching was disabled due to Expires in the past,
"Cache-Control: no-cache" or "Cache-Control: max-age=0", caching was not
used if it was cacheable as per subsequently parsed X-Accel-Expires header.
Fix is to avoid disabling caching immediately after parsing Expires in
the past or Cache-Control, but rather set flags which are later checked by
ngx_http_upstream_process_headers() (and cleared by "Cache-Control: max-age"
Additionally, now X-Accel-Expires does not prevent parsing of cache control
extensions, notably stale-while-revalidate and stale-if-error. This
ensures that order of the X-Accel-Expires and Cache-Control headers is not
Prodded by Vadim Fedorenko and Yugo Horie.
2 files changed