在PHP中使用正则表达式找出子域 [英] Find out subdomain using Regular Expression in PHP

问题描述

很抱歉，如果这对作为堆栈溢出问题的挑战来说太少了，但我对正则表达式还是陌生的.

Sorry if this is too little of a challenge to be suited as a stack overflow question, but I'm kind of new to Regular Expressions.

我的问题是，下面所有示例返回字符串"token"的正则表达式是什么?

My question is, what is the regular expression that returns the string "token" for all the examples bellow?

• token.domain.com
• token.domain.com/
• token.domain.com/index.php
• token.domain.com/folder/index.php
• token.domain.com/folder/subfolder
• token.domain.com/folder/subfolder/index.php
• (在编辑后添加)
• domain.com
• domain.com/

• token.domain.com
• token.domain.com/
• token.domain.com/index.php
• token.domain.com/folder/index.php
• token.domain.com/folder/subfolder
• token.domain.com/folder/subfolder/index.php
• (added after edit)
• domain.com
• domain.com/

我试图在preg_replace函数内部使用，以便从$ _SERVER ['SERVER_NAME']变量中找出当前页面的子域.

Im trying to use inside an preg_replace function in order to find out the subdomain of the current page from the $_SERVER['SERVER_NAME'] variable.

预先感谢您， tilt

Thank you in advance, titel

编辑说明:对不起，混乱和自负，我编辑了我的问题，最初的意思是我忘了写了，因为它完全可以在没有任何子域的情况下工作-在这种情况下它将返回空字符串或NULL

Edit note: Sorry chaos and sebnow , I edited my question, what I initially meant, but forgot to write, was that this would work without any subdomain at all - case in which it would return an empty sting or NULL

推荐答案

preg_replace('/^(?:([^\.]+)\.)?domain\.com$/', '\1', $_SERVER['SERVER_NAME'])

编辑:以下内容为您提供了什么?

What does the following output for you:

<?php
    echo preg_replace('/^(?:([^\.]+)\.)?domain\.com$/', '\1', "sean.domain.com") . "<br />";
    echo preg_replace('/^(?:([^\.]+)\.)?domain\.com$/', '\1', "titel.domain.com") . "<br />";
    echo preg_replace('/^(?:([^\.]+)\.)?domain\.com$/', '\1', "domain.com") . "<br />";
?>

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