how the drupal set css/js query string for cache buster

缓存破解与版本更新

原创于 2012-12-13 17:31:35 发布 · 233 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#php

web 专栏收录该内容

47 篇文章

订阅专栏

本文探讨了如何通过在CSS/JS文件URL后附加随机字符串来破解浏览器、CDN或Varnish缓存，确保当发布新版本时，客户端能够获取到最新文件。介绍了随机字符串的生成方式及在Drupal中的实现细节。

Css/js can be cached by browser, CDN or Varnish cache. If a new version css/js released, we want browser/CDN/Varnish request drupal to get new version.

Drupal will append a random string to css/jss url to work as cache buster.

[How to generate query string?]
This random string is stored in DB variable table by default, named as ‘css_js_query_string’. When common.inc drupal_flush_all_caches() is called, it will call _drupal_flush_css_js() then generate a random string with 6 characters.

We can also hard code the value in settings.php.

[How to use the query string?]
In common.inc drupal_pre_render_styles() function, it will call variable_get(‘css_js_query_string’,0) to get the value and append on each css.