Creating virtual pages?

Question

CMS

there is an array there is a function
$array = array('page-1','page-2','page-3');

function page_content(){
  echo 'hellow world';
}

how to make pages available with the content of the page_content function displayed on them at the following addresses:

• domain.com/page-1.php
  
• domain.com/page-2.php
  
• domain.com/page-3.php
  

without their physical creation
Throw off pliz links to explanations of the algorithm how this is done.

Answer 1

1. We register all requests for one file in .htaccess:

RewriteRule .* index.php [L]

2. Then, in php, based on $_SERVER['REQUEST_URI'] we do routing: if the required ending is contained in the query string, we return the content, if not - 404.
(use: preg_match + switch-case-default )

Answer 2

Break the url by a slash, remove the .php extension, and use in_array() to check if the url and the array element match