<?php

// Start the timer so we can track the page load time
$start = microtime();

function getMicroTime($t)
{
    list($usec, $sec) = explode(" ", $t);
    return ((float) $usec + (float) $sec);
}

$seconds_cache_redis = 60 * 60 * 12; // 12 hours by default, you can change in this in wp-admin options page
$ip_of_your_website  = '127.0.0.1'; //You must set this to the IP of your website
$secret_string       = "changeme";
/*This is if you want to manually refresh the cache
ex: http://example.com/sample-post?refresh=changeme    */

// so we don't confuse the cloudflare server 
if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) {
    $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_CF_CONNECTING_IP'];
}

define('WP_USE_THEMES', true);
$current_url = "http://" . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
$current_url = str_replace("?refresh=$secret_string", '', $current_url); //clean up the URL
$current_url = str_replace("&refresh=$secret_string", '', $current_url);
$redis_key = md5($current_url);

try {
	// check if PECL Extension is available
	if (class_exists('Redis')) {
		$redis = new Redis();
		
		// Sockets can be used as well '/tmp/redis.sock'
		// documentation can be found at https://github.com/nicolasff/phpredis/#connection
		$redis->connect('127.0.0.1');
		
	} else // Fallback to predis5.2.php
	{
		include("wp-content/plugins/wp-redis-cache/predis5.2.php"); //we need this to use Redis inside of PHP
		$redis = new Predis_Client();
	}
} catch (Exception $e) {
	$redisError=true;
}

//Either manual refresh cache by adding ?refresh=secret_string after the URL or somebody posting a comment
if (!isset($redisError) && (isset($_GET['refresh']) || $_GET['refresh'] == $secret_string || ($_SERVER['HTTP_REFERER'] == $current_url && $_SERVER['REQUEST_URI'] != '/' && $_SERVER['REMOTE_ADDR'] != $ip_of_your_website))) {
    
    $redis->del($redis_key);
    require('./wp-blog-header.php');
    
    // This page is cached, lets display it
} else if ($redis->exists($redis_key)) {
    $html_of_page = $redis->get($redis_key);
    echo $html_of_page;
    
    // If the cache does not exist lets display the user the normal page without cache, and then fetch a new cache page
} else if ($_SERVER['REMOTE_ADDR'] != $ip_of_your_website && strstr($current_url, 'preview=true') == false) {
    
    if ($_SERVER['REQUEST_METHOD'] === 'POST') {
        $isPOST = 1;
    } else {
        $isPOST = 0;
    }
    
    $loggedIn = preg_match("/wordpress_logged_in/", var_export($_COOKIE, true));
    if ($isPost == 0 && $loggedIn == 0) {
        ob_start();
        require('./wp-blog-header.php');
        $html_of_page = ob_get_contents();
        ob_end_clean();
        echo $html_of_page;
        
        $usr_seconds = get_option('wp-redis-cache-seconds'); //if the user has the seconds defined in the admin section use it
        if (isset($usr_seconds) && is_numeric($usr_seconds)) {
            $seconds_cache_redis = $usr_seconds;
        }
        
        if (strlen($html_of_page) > 5000) {   //prevents caching error pages 
            $redis->setex($redis_key, $seconds_cache_redis, $html_of_page);
        }
    } else //either the user is logged in, or is posting a comment, show them uncached
        {
        require('./wp-blog-header.php');
    }
    
} else if (($_SERVER['REMOTE_ADDR'] != $ip_of_your_website && strstr($current_url, 'preview=true') == true) || isset($redisError)) {
    require('./wp-blog-header.php');
}
 // else {   // This is what your server should get if no cache exists  //depricated, as the ob_start() is cleaner
    // require('./wp-blog-header.php');
// }


if ($_SERVER['REMOTE_ADDR'] != $ip_of_your_website) {
    // How long did it take to load the page? (CloudFlare may strip out comments)
    $end  = microtime();
    $time = (@getMicroTime($end) - @getMicroTime($start));
    echo "<!-- Cache system by Benjamin Adams. Page generated in " . round($time, 5) . " seconds. -->";
}