$ _SERVER ['SERVER_NAME']和$ _SERVER ['HTTP_HOST']都与实际网址不同

Question

When accessing the URL www.domain.com/test.php, both $_SERVER['SERVER_NAME'] and $_SERVER['HTTP_HOST'] output the domain name without the www. prefix: domain.com

Why would that be this way ?

EDIT: as stated here, $_SERVER['SERVER_NAME'] could be different than the actual requested URL, however $_SERVER['HTTP_HOST'] should return the domain.

PHP version: 7.1 Apache version : 2.2

.htaccess content is as follow (the interesting part is the top rewrite block)

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
    RewriteRule ^(.*)$ https://%1/$1 [R=301,L]
</IfModule>

# BEGIN Force SSL for SAKURA
# RewriteしてもHTTPS環境変数を有効にする
SetEnvIf REDIRECT_HTTPS (.*) HTTPS=$1


# 常時HTTPS化(HTTPSが無効な場合リダイレクト)
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{ENV:HTTPS} !on
RewriteCond %{REQUEST_URI} !/wp-cron\.php$
RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
</IfModule>
# END Force SSL for SAKURA

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

And here is the content of test.php:

<?php 
echo $_SERVER['SERVER_NAME'];

echo  $_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];

Output is "domain.com" and "domain.com/test".

Answer 1

Well that top interesting rewrite block you mentioned is removing the www. from the URL with a 301 redirect. So there's no way of a request getting to your PHP script with the www. intact, because any request including the www. is issued a 301 redirect and never gets to the PHP script. The browser is then re-issuing the request based on the 301 redirect, and now it gets to your script without the www..

You can test this by commenting out that top block, clearing your browser cache (important - or using a different browser), and visiting the test page again.