| 2 | | ngx_http_upstream_process_cache_control in ngx_http_upstream.c |
| 3 | | {{{ |
| 4 | | 4738 if (r->cache->valid_sec != 0 && u->headers_in.x_accel_expires != NULL) { |
| 5 | | 4739 return NGX_OK; |
| 6 | | 4740 } |
| 7 | | 4741 |
| 8 | | 4742 start = h->value.data; |
| 9 | | 4743 last = start + h->value.len; |
| 10 | | 4744 |
| 11 | | 4745 if (ngx_strlcasestrn(start, last, (u_char *) "no-cache", 8 - 1) != NULL |
| 12 | | 4746 || ngx_strlcasestrn(start, last, (u_char *) "no-store", 8 - 1) != NULL |
| 13 | | 4747 || ngx_strlcasestrn(start, last, (u_char *) "private", 7 - 1) != NULL) |
| 14 | | 4748 { |
| 15 | | 4749 u->cacheable = 0; |
| 16 | | 4750 return NGX_OK; |
| 17 | | 4751 } |
| 18 | | }}} |
| 19 | | |
| 20 | | If Cache-Control from upstream has a value of no-store, no-cache or private, u->cacheable = 0; in ngx_http_upstream_process_cache_control. |
| 21 | | |
| 22 | | In the case of before processing ngx_http_upstream_process_accel_expires, if it sets u->cacheable = 0 for this procedure, it does not cache according to Cache-Control. X-Accel-Expires is only overwriting valid_sec. |
| 23 | | |
| 24 | | OTOH, In the case of after processing ngx_http_upstream_process_accel_expires, ngx_http_upstream_process_cache_control returns NGX_OK earlier than the procedure of Cache-Control: no-xxx or private. |
| 25 | | In this case, it does cache, the cache is following x-accel-expires values. It ignores Cache-Control. |
| 26 | | |
| 27 | | As this result it seems not to override entirely Cache-Control by X-Accel-Expires. And It has differential behavor according to order of upstream header. |
| | 2 | https://forum.nginx.org/read.php?2,219520,293374#msg-293374 |
| | 3 | it seems not to override entirely Cache-Control by X-Accel-Expires. And It has differential behavor according to order of upstream header. |
