Mercurial > hg > nginx-site
comparison xml/en/docs/http/ngx_http_proxy_module.xml @ 1912:ec4af97e4403
Split off header options from parameters in proxy_cache_use_stale and friends.
author | Yaroslav Zhuravlev <yar@nginx.com> |
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date | Tue, 21 Feb 2017 21:23:53 +0300 |
parents | 41cf2c2d8c5c |
children | 66a30a380fba |
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1911:f024ac0ec5c7 | 1912:ec4af97e4403 |
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8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> | 8 <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> |
9 | 9 |
10 <module name="Module ngx_http_proxy_module" | 10 <module name="Module ngx_http_proxy_module" |
11 link="/en/docs/http/ngx_http_proxy_module.html" | 11 link="/en/docs/http/ngx_http_proxy_module.html" |
12 lang="en" | 12 lang="en" |
13 rev="56"> | 13 rev="57"> |
14 | 14 |
15 <section id="summary"> | 15 <section id="summary"> |
16 | 16 |
17 <para> | 17 <para> |
18 The <literal>ngx_http_proxy_module</literal> module allows passing | 18 The <literal>ngx_http_proxy_module</literal> module allows passing |
647 | 647 |
648 <para> | 648 <para> |
649 The <literal>error</literal> parameter also permits | 649 The <literal>error</literal> parameter also permits |
650 using a stale cached response if a proxied server to process a request | 650 using a stale cached response if a proxied server to process a request |
651 cannot be selected. | 651 cannot be selected. |
652 The same behavior can be enabled with the | |
653 “<link url="https://tools.ietf.org/html/rfc5861#section-4">stale-if-error</link>” | |
654 extension of the <header>Cache-Control</header> response header field (1.11.10) | |
655 for a specified number of seconds after the response became stale, | |
656 however, this has lower priority than using the directive parameter. | |
657 </para> | 652 </para> |
658 | 653 |
659 <para id="proxy_cache_use_stale_updating"> | 654 <para id="proxy_cache_use_stale_updating"> |
660 Additionally, the <literal>updating</literal> parameter permits | 655 Additionally, the <literal>updating</literal> parameter permits |
661 using a stale cached response if it is currently being updated. | 656 using a stale cached response if it is currently being updated. |
662 This allows minimizing the number of accesses to proxied servers | 657 This allows minimizing the number of accesses to proxied servers |
663 when updating cached data. | 658 when updating cached data. |
664 The same behavior can be enabled with the | 659 </para> |
660 | |
661 <para> | |
662 Using a stale cached response | |
663 can also be enabled directly in the response header | |
664 for a specified number of seconds after the response became stale (1.11.10). | |
665 This has lower priority than using the directive parameters. | |
666 <list type="bullet" compact="no"> | |
667 | |
668 <listitem> | |
669 The | |
665 “<link url="https://tools.ietf.org/html/rfc5861#section-3">stale-while-revalidate</link>” | 670 “<link url="https://tools.ietf.org/html/rfc5861#section-3">stale-while-revalidate</link>” |
666 extension of the <header>Cache-Control</header> response header field (1.11.10) | 671 extension of the <header>Cache-Control</header> header field permits |
667 for a specified number of seconds after the response became stale, | 672 using a stale cached response if it is currently being updated. |
668 however, this has lower priority than using the directive parameter. | 673 </listitem> |
674 | |
675 <listitem> | |
676 The | |
677 “<link url="https://tools.ietf.org/html/rfc5861#section-4">stale-if-error</link>” | |
678 extension of the <header>Cache-Control</header> header field permits | |
679 using a stale cached response in case of an error. | |
680 </listitem> | |
681 | |
682 </list> | |
669 </para> | 683 </para> |
670 | 684 |
671 <para> | 685 <para> |
672 To minimize the number of accesses to proxied servers when | 686 To minimize the number of accesses to proxied servers when |
673 populating a new cache element, the <link id="proxy_cache_lock"/> | 687 populating a new cache element, the <link id="proxy_cache_lock"/> |