PHP - Change every url in html depending on domain - php

Question

Using PHP I would like to be able to change every url in a specific HTML page depending on domain.
This code allows me to change urls one by one but I'm sure there is a better way:
$domain = $_SERVER['SERVER_NAME'];
switch ($domain) {
case "example2.com":
$url1 = "http://".$domain."/secondsubfolder/thispage.html";
break;
case "example3.com":
$url1 = "http://".$domain."/thirdsubfolder/thispage.html";
break;
default:
$url1 = "http://example.com/firstsubfolder/thispage.html";
}
HTML:
first url
Notice that I also need to change the first subfolder depending on domain, thats why I can't use relative urls.
So my aim is to be able change every url in my default HTML code:
hello
bye
should change if my website is accessed through example2.com
<a href="example2.com/secondsubfolder/thispage.html" >hello</a>
bye

Answer 1

Your question isn't very clear to me but I guess you need something like:
<?php
$domain = $_SERVER['SERVER_NAME'];
$scriptPath = $_SERVER['SCRIPT_NAME'];
switch ($domain) {
case "example2.com":
$domain = "example2.com";
$folder = "secondsubfolder";
break;
case "example3.com":
$domain = "example3.com";
$folder = "thirdsubfolder";
break;
default:
$domain = "example.com";
$folder = "thirdsubfolder";
}
$scriptPath = preg_replace('%^/.*?/%', "/$folder/", $scriptPath);
echo "http://{$domain}{$scriptPath}";