在RewriteCond中做什么双冒号? [英] What Double Colon does in RewriteCond?

问题描述

示例:

RewriteCond %{REQUEST_URI}::$1 ^(.*?)/?(.*)::\2$

看起来像这个运算符在任何参考书或手册中都找不到.我在哪里可以找到它，或者任何人都可以解释该运算符的作用?

Looks like this operator is nowhere to find in any reference or manual. Where can I find it or anyone could explain what this operator does?

推荐答案

规则如下:

RewriteCond %{REQUEST_URI}::$1 ^(.*?/)(.*)::\2$
RewriteRule ^(.*)$ - [E=BASE:%1]

也可以写成(在条件的任何一侧使用##作为固定的定界符):

can also be written as (using ## as fixed delimiter on either side of condition):

RewriteCond %{REQUEST_URI}##$1 ^(.*?/)(.*)##\2$
RewriteRule ^(.*)$ - [E=BASE:%1]

说明:

• 您可以使用从RewriteCond中的RewriteRule捕获的$1，因为mod_rewrite实际上向后处理规则集.它以RewriteRule中的模式开头，如果匹配，则继续检查一个或多个RewriteCond.
• 因此您可以在RewriteCond中看到，LHS(左侧/测试字符串)可以使用反向引用变量，例如$1，$2或%1，%2等，但是RHS(右侧)，即条件字符串不能使用，这些$1，$2或%1，%2变量.
• 在RHS条件部分中，我们只能使用的<反向引用>是内部反向引用，即我们在此条件本身中捕获的组.它们用\1，\2等表示.
• 在您的RewriteCond中，第一个捕获的组是(.*?/).它将由内部后向引用\1表示.
• 您可以指出，该规则基本上是通过比较%{REQUEST_URI}和$1动态地找到RewriteBase . %{REQUEST_URI}的示例将是/directory/foobar.php，而同一示例URI的$1的示例将是foobar.php. ^(.*?/)::(.*)\1$将差异放在第一个捕获的组%1或\1中.在这里，它将使用值/directory/填充%1或\1，稍后将在设置环境变量%{ENV:BASE}时使用该值，即E=BASE:%1.

• You could use $1 captured from RewriteRule in your RewriteCond because mod_rewrite actually processes a ruleset backwards. It starts with the pattern in the RewriteRule, and if it matches, goes on to check the one or more RewriteCond.
• So as you can see in a RewriteCond, the LHS (left-hand side / test string) can use backreference variables e.g. $1, $2 OR %1, %2 etc but RHS (right-hand side) i.e. condition string cannot use these $1, $2 OR %1, %2 variables.
• Inside the RHS condition part only backreference we can use are internal back-references i.e. the groups we have captured in this condition itself. They are denoted by \1, \2 etc.
• In your RewriteCond first captured group is (.*?/). It will be represented by internal back-reference \1.
• As you can mark out that this rule is basically finding RewriteBase dynamically by comparing %{REQUEST_URI} and $1. An example of %{REQUEST_URI} will be /directory/foobar.php and example of $1 for same example URI will be foobar.php. ^(.*?/)::(.*)\1$ is putting the difference in 1st captured group %1 or \1. Here it will populate %1 or \1 with the value /directory/ which is used later in setting up env variable %{ENV:BASE} i.e. E=BASE:%1.

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