Create a entire request cache file and serve it instead of exucete all code each time (also in my CMS i add an webhook/event that open url /cache/clear-all for clear all cache when i update data)

simple-entire-request-cache.php

<?php

$url = $_SERVER["REQUEST_URI"];

// clear all cache 
if ($url == '/cache/clear-all') {
    array_map('unlink', glob("cache/*.html"));
    exit('Cache clear successfully!');
}

// # format url and create cache filename
$url = $url == '/' ? 'home' : $url; // if root its home
$url = str_replace('/', '', $url); // remove initial slash
$cachefile = 'cache/cached-'.$url.'.html';
$cache_cp_generated = "<!-- Cached copy, generated ".date('H:i:s')." -->\n";
//$cachetime = 18000; // @time4cache: uncomment also "if condition"

// Serve from the cache if it is younger than $cachetime
if (file_exists($cachefile)) { // && time() - $cachetime < filemtime($cachefile) // @time4cache
    readfile($cachefile);
    exit;
}
ob_start(); // Start the output buffer
?>

<?php
    // All your application code goes here 
    // (i'm print also $cache_cp_generated in head tag for know from html source if its a cache copy) 
?>

<?php
// Cache the contents to a cache file
$cached = fopen($cachefile, 'w');
fwrite($cached, ob_get_contents());
fclose($cached);
ob_end_flush(); // Send the output to the browser

// improvment for me of this article: https://dzone.com/articles/how-to-create-a-simple-and-efficient-php-cache
?>