Apache HTTPD RewriteRule中的^和$是什么意思？

问题描述

我已成功将以下代码添加到我的Apache HTTPD配置中：

I have successfully added the following code to my Apache HTTPD configuration:

# Force www.
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ https://www.%{HTTP_HOST}/$1 [R=301,L]
# Force https (SSL)
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

虽然可以正常工作，但我有一个理论上的问题：

Although it works as expected, I have a theoretical question:

为什么会有 ^ 和 $ 在第三行中强制执行 www。，而不在第六行中强制执行 https？

Why are there a ^ and $ in 3rd line enforcing "www.", and not in the 6th line enforcing "https"?

此致，Dovid。

推荐答案

对于您的两个正则表达式模式 ^（。*）$ 和（。*）的行为相同。不过，请猜测，您不需要使用任何一个。实际上，不使用。* 并使用与匹配的％{REQUEST_URI} 变量的错误发生率要低得多。完整URI（不是相对的URI，例如。* ）。因此，我建议将您的规则更改为：

For both of your regex patterns ^(.*)$ and (.*) will behave same. However guess what, you don't need to use any of them. In fact it is far less error prone also to not to use .* and use %{REQUEST_URI} variable that matches full URI (not the relative one like .*). So I suggest change your rules to this:

# Force www.
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^ https://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L,NE]

# Force https (SSL)
RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L,NE]

• 标志 NE 用于避免转义。如果您的原始URI有一些特殊字符，例如＃或（，），[，] 等。
上面的 RewriteRule 模式中的

• ^ 只会返回每次匹配都为true，因为 ^ 表示字符串的开始位置，并且始终匹配。


• 两个规则都可以组合为一个


• Flag NE is used for not escaping. It is useful to have this flag in case your original URI has some special characters like # or (,),[,] etc.
• ^ in RewriteRule pattern above does nothing but returns true for every match since ^ means start position of a string and it will be always match.
• Both rules can be combined into a single rule but it will look a bit complicated.

这里是：

RewriteCond %{HTTP_HOST} !^www\. [NC,OR]
RewriteCond %{HTTPS} !on
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ https://www.%1%{REQUEST_URI} [R=301,L,NE]

此处是此规则的解释：



• RewriteCond％{HTTP_HOST}！^ www\。 [NC，OR] ：如果 HOST_NAME 不是以 www开头。


• [NC，OR] ：忽略大小写匹配和 OR 的下一个条件


• RewriteCond％{HTTPS}！on ： HTTPS 未打开


• RewriteCond％{HTTP_HOST} ^（?: www\。）？（。+）$ [NC] ：始终匹配，因为 www。在此处是可选匹配。它用于捕获 HTTP_HOST 的子字符串，而无需使用（。+）启动 www。。捕获组＃1中的模式（以后将被反向引用为％1 ）。请注意，（？：..）是一个非捕获组。


• RewriteRule ^ https：/ /www.%1%{REQUEST_URI} [R = 301，L，NE] ： ^ 将始终匹配。该规则将通过添加到 R = 301 代码重定向到 https：//www.%1% {REQUEST_URI} https：// 和 www。到％1 。如上所述，％1 是 RewriteCond 中捕获组＃1的后向引用。


• RewriteCond %{HTTP_HOST} !^www\. [NC,OR]: if HOST_NAME doesn't start with www.
• [NC,OR]: Ignore case match and ORs next condition
• RewriteCond %{HTTPS} !on: HTTPS is not turned on
• RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]: This condition will always match since www. is an optional match here. It is used to capture substring of HTTP_HOST without starting www. by using (.+) pattern in capture group #1 (to be back-referenced as %1 later). Note that (?:..) is a non-capturing group.
• RewriteRule ^ https://www.%1%{REQUEST_URI} [R=301,L,NE]: ^ will always match. This rule will redirect to https://www.%1%{REQUEST_URI} with R=301 code by adding https:// and www. to %1. %1 is back-reference of capture group #1 from RewriteCond, as mentioned above.

这篇关于Apache HTTPD RewriteRule中的^和$是什么意思？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！