Implementing Caching Strategies in PHP to Improve User Experience

As the internet evolves, user experience becomes crucial for website development, and an effective caching strategy can boost performance for PHP applications by reducing database queries, lowering server load, and speeding up page loads.

File System Based Cache

File system caching stores serialized data in files and reads it back via deserialization, suitable for small data due to slower I/O. Example implementation:

<?php

function get_data_from_cache($key) {
    $filename = "/tmp/" . md5($key) . ".cache";
    if (file_exists($filename)) {
        $file_content = file_get_contents($filename);
        $data = unserialize($file_content);
        if ($data['exp_time'] > time()) {
            return $data['value'];
        } else {
            unlink($filename);
        }
    }
    return null;
}

function set_data_to_cache($key, $value, $exp_time = 3600) {
    $filename = "/tmp/" . md5($key) . ".cache";
    $data = [
        'exp_time' => time() + $exp_time,
        'value' => $value,
    ];
    $file_content = serialize($data);
    file_put_contents($filename, $file_content);
}

?>

Memory Based Cache

Memory caches keep data in RAM for faster access. Common PHP memory caches include Memcache and Redis. Example implementations:

Memcache

<?php

$memcache = new Memcache();
$memcache->connect("127.0.0.1", 11211) or die ("Could not connect");

// Retrieve data from cache
function get_data_from_memcache($key) {
    global $memcache;
    $data = $memcache->get(md5($key));
    return $data ? $data : null;
}

// Store data in cache
function set_data_to_memcache($key, $value, $exp_time = 3600) {
    global $memcache;
    $memcache->set(md5($key), $value, false, $exp_time);
}

?>

Redis

<?php

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$redis->auth('password');

// Retrieve data from cache
function get_data_from_redis($key) {
    global $redis;
    $data = $redis->get(md5($key));
    return $data ? $data : null;
}

// Store data in cache
function set_data_to_redis($key, $value, $exp_time = 3600) {
    global $redis;
    $redis->set(md5($key), $value, $exp_time);
}

?>

Framework Based Cache

Most PHP frameworks provide built‑in cache components. Using Laravel as an example, the article shows how to install Laravel, configure Redis as the cache driver, and use the Cache facade to get and set cached data.

Install Laravel

composer create-project --prefer-dist laravel/laravel blog

Set Cache Driver

Edit the .env file to set CACHE_DRIVER=redis and add Redis configuration in config/database.php as shown.

...
'redis' => [
    'client' => 'predis',
    'default' => [
        'host' => env('REDIS_HOST', '127.0.0.1'),
        'password' => env('REDIS_PASSWORD', null),
        'port' => env('REDIS_PORT', 6379),
        'database' => 0,
    ],
],
...

Use Cache Component

<?php

use Illuminate\Support\Facades\Cache;

// Retrieve data from cache
function get_data_from_laravel_cache($key) {
    return Cache::get(md5($key));
}

// Store data in cache
function set_data_to_laravel_cache($key, $value, $exp_time = 3600) {
    Cache::put(md5($key), $value, $exp_time);
}

?>

By storing data in caches, applications avoid repeated database access, greatly improving response speed and user experience. Proper cache expiration, invalidation, and update mechanisms are essential to prevent stale data.