我正在使用以下內容在我的主網站上強制使用 HTTPS。

### Force SSL
RewriteCond %{HTTPS} !=on
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

如果你想查看完整的 htaccess 文件，我把它放在下面：

<IfModule mod_rewrite.c>

   RewriteEngine On
   RewriteBase /

   ### Blacklist via Referrers

   RewriteCond %{HTTP_REFERER} removed\.net [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.net [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.sx [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.com [NC,OR]
   RewriteCond %{HTTP_REFERER} removed\.org [NC]
   RewriteRule ^(.*)$ - [F,L]

   ### Force SSL
   #RewriteCond %{HTTPS} !=on
   #RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

   ### Canonicalize codeigniter URLs

   # If your default controller is something other than
   # "welcome" you should probably change this
   RewriteRule ^(welcome(/index)?|index(\.php)?)/?$ / [L,R=301]
   RewriteRule ^(.*)/index/?$ $1 [L,R=301]

   # Removes trailing slashes (prevents SEO duplicate content issues)
   RewriteCond %{REQUEST_FILENAME} !-d
   RewriteRule ^(.+)/$ $1 [L,R=301]

   # Enforce NO www
   RewriteCond %{HTTP_HOST} ^www [NC]
   RewriteRule ^(.*)$ https://removed.com/$1 [L,R=301]

   # Removes access to the system folder by users.
   # Additionally this will allow you to create a System.php controller,
   # previously this would not have been possible.
   # 'system' can be replaced if you have renamed your system folder.
   RewriteCond %{REQUEST_URI} ^system.*
   RewriteRule ^(.*)$ /index.php/$1 [L]

   # Checks to see if the user is attempting to access a valid file,
   # such as an image or css document, if this isn't true it sends the
   # request to index.php
   RewriteCond %{REQUEST_FILENAME} !-f
   RewriteCond %{REQUEST_FILENAME} !-d
   RewriteRule ^(.*)$ index.php/$1 [L]

</IfModule>

<IfModule !mod_rewrite.c>

   # Without mod_rewrite, route 404's to the front controller
   ErrorDocument 404 /index.php

</IfModule>

我正在努力弄清楚重定向循環是如何發生的。

更新

我沒有明確說明我的 Web 伺服器 (Apache) 僅在埠 80 上配置了一個虛擬主機，該主機將 HTTP 和 HTTPS 流量通過負載平衡器定向到它。負載均衡器處理 SSL 連接。

感謝HBruijn 的評論，我明白了為什麼我得到了重定向循環。

來自 ELB 的流量將始終是 HTTP，因為它處理到使用者的 HTTPS 流量，但到伺服器的流量是 HTTP，所以我之前的規則將導致循環。

經過一些研究，我發現負載均衡器會轉發一些有用的標頭，例如X-Forwarded-Proto. 這可用於確定客戶端是使用 HTTP 還是 HTTPS，如下所示：

### Force HTTPS
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

我希望以上內容在嘗試在 Amazon Web Services 負載均衡器後面強制使用 HTTPS 時對其他人有所幫助。

引用自：https://serverfault.com/questions/677560