Entity tags: explicit flag to skip not modified filter.

Previously, last_modified_time was tested against -1 to check if the
not modified filter should be skipped.  Notably, this prevented nginx
from additional If-Modified-Since (et al.) checks on proxied responses.
Such behaviour is suboptimal in some cases though, as checks are always
skipped on responses from a cache with ETag only (without Last-Modified),
resulting in If-None-Match being ignored in such cases.  Additionally,
it was not possible to return 412 from the If-Unmodified-Since if last
modification time was not known for some reason.

This change introduces explicit r->disable_not_modified flag instead,
which is set by ngx_http_upstream_process_headers().
3 files changed
tree: f50b9d0a6c83a44518e798d6394eda7d7a7ba1de
  1. auto/
  2. conf/
  3. contrib/
  4. docs/
  5. misc/
  6. src/
  7. .hgtags