在 .htaccess 中自动检测域名

Question

我想删除 www 并直接指向域的非 www 版本，经过一些研究，我发现下面这两行可以完成这项工作：

RewriteCond %{HTTP_HOST} !^domain.com$ [NC]
RewriteRule ^(.*)$ http://domain.com/$1 [L,R=301]

但是，当我将以上两行添加到下面的当前 .htaccess 文件中时，是否需要将 domain.com 位更改为网站域？如果是这样，我该如何更改它以便它自己知道域名？所以我不必手动更改它。

我发现这个article 可能是这个问题的答案，但我只是不知道如何实施它我不是真正的专家，但我知道一个错误会破坏一切，请帮助。

DirectoryIndex index.html index.php 
ErrorDocument 404 /404 

RewriteEngine On 
RewriteBase / 

# remove enter code here.php; use THE_REQUEST to prevent infinite loops 
# By puting the L-flag here, the request gets redirected immediately 
RewriteCond %{THE_REQUEST} ^GET\ (.*)\.php\ HTTP 
RewriteRule (.*)\.php$ $1 [R=301,L] 

# remove index 
# By puting the L-flag here, the request gets redirected immediately 
# The trailing slash is removed in a next request, so be efficient and 
# dont put it on there at all 
RewriteRule (.*)/index$ $1 [R=301,L] 

# remove slash if not directory 
# By puting the L-flag here, the request gets redirected immediately 
RewriteCond %{REQUEST_FILENAME} !-d 
RewriteCond %{REQUEST_URI} /$ 
RewriteRule (.*)/ $1 [R=301,L] 

# add .php to access file, but don't redirect 
# On some hosts RewriteCond %{REQUEST_FILENAME}.php -f will be true, even if 
# no such file exists. Be safe and add an extra condition 
# There is no point in escaping a dot in a string 
RewriteCond %{REQUEST_FILENAME}.php -f 
RewriteCond %{REQUEST_URI} !(/|\.php)$ 
RewriteRule (.*) $1.php [L]

Answer 1

如果您只想将www.example.com 重定向到example.com，您可以简单地匹配www.。如果您想重定向每个子域（通常不是这种情况），您可以匹配并尝试匹配，如果它有两个部分。将example.com 更改为您自己的域名通常更容易。在任何情况下，您都应该在任何其他规则之前添加该规则。

#Option 1: Only redirect if it begins with www.
RewriteCond %{HTTP_HOST} ^www\.(.*)$
RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]

#Option 2: Redirect all the things! (including thingy.sub.domain.example.com to example.com)
RewriteCond %{HTTP_HOST} ^.*\.([^\.]+\.[^\.]+)$
RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]