Build a WordPress Cache Plugin for Dynamic Web Pages

WordPress is one of the most popular content management systems (CMS) in the world, powering over 40% of all websites on the internet. However, as a website grows, it can become slower and less responsive, which can negatively impact user experience and search engine rankings. One solution to this problem is to implement a cache plugin, which can significantly speed up a website’s performance.

In this tutorial, we will guide you through the process of building a WordPress cache plugin for dynamic web pages.

Step 1: Set up the Plugin Infrastructure First, create a new folder in the wp-content/plugins directory of your WordPress installation. In this folder, create a new PHP file named “dynamic-cache.php”, which will be the main plugin file. At the beginning of the file, add the following PHP code:

/*
Plugin Name: Dynamic Cache
Description: A cache plugin for dynamic web pages
Version: 1.0
Author: Your Name
*/
defined('ABSPATH') or die('No script kiddies please!');

This code sets up the basic plugin infrastructure and adds some basic information about the plugin.

Step 2: Add a Function to Check if the Page is Cacheable The next step is to add a function that will check whether a page is cacheable. In this case, we will use a simple rule that checks if the page is not the login page, and is not being accessed by a logged-in user. Add the following code to the “dynamic-cache.php” file:

function is_cacheable() {
  return !is_user_logged_in() && !is_page('wp-login.php');
}

This function returns true if the page is cacheable, and false otherwise.

Step 3: Add a Function to Get the Cache Key The next step is to add a function that will generate a unique cache key for each page. This key will be used to store and retrieve the cached version of the page. Add the following code to the “dynamic-cache.php” file:

function get_cache_key() {
  return 'dynamic-cache-' . md5($_SERVER['REQUEST_URI']);
}

This function generates a unique cache key based on the current request URI.

Step 4: Add a Function to Get the Cached Page The next step is to add a function that will retrieve the cached version of the page if it exists. Add the following code to the “dynamic-cache.php” file:

function get_cached_page() {
  $cache_key = get_cache_key();
  $cache = wp_cache_get($cache_key, 'dynamic-cache');
  if ($cache !== false) {
    echo $cache;
    exit;
  }
}

This function checks if the page is cacheable, generates a cache key, and then retrieves the cached version of the page if it exists. If the cached version exists, it is outputted and the script is exited.

Step 5: Add a Function to Cache the Page The next step is to add a function that will cache the current page if it is cacheable. Add the following code to the “dynamic-cache.php” file:

function cache_page($content) {
  if (is_cacheable()) {
    $cache_key = get_cache_key();
    wp_cache_set($cache_key, $content, 'dynamic-cache');
  }
  return $content;
}
add_filter('wp_head', 'get_cached_page', 1);
add_filter('wp_footer', 'cache_page', 100);

This function checks if the page is cacheable, generates a cache key, and then caches the page using the WordPress cache API.

Step 6: Test the Plugin Finally, save the “dynamic-cache.php” file and activate the plugin in the WordPress