Upstream: avoid closing client connection in edge case.

If proxy_cache is enabled, and proxy_no_cache tests true, it was previously
possible for the client connection to be closed after a 304. The fix is to
recheck r->header_only after the final cacheability is determined, and end the
request if no longer cacheable.

Example configuration:

proxy_cache foo;
proxy_cache_bypass 1;
proxy_no_cache 1;

If a client sends If-None-Match, and the upstream server returns 200 with a
matching ETag, no body should be returned to the client. At the start of
ngx_http_upstream_send_response proxy_no_cache is not yet tested, thus cacheable
is still 1 and downstream_error is set.

However, by the time the downstream_error check is done in process_request,
proxy_no_cache has been tested and cacheable is set to 0. The client connection
is then closed, regardless of keepalive.
1 file changed
tree: e718afe8714aeab2f4a56e023b0d028878a8de96
  1. auto/
  2. conf/
  3. contrib/
  4. docs/
  5. misc/
  6. src/
  7. .hgtags