A simple PHP file based cache with support for cache expiry and storing any data type or structure

cache.php

<?php

/*
 * A simple PHP file based cache with support for cache expiry and storing any data type or structure
 *
 * Released with the karmaware tag - https://pete-rai.github.io/karmaware
 *
 * Website  : http://www.rai.org.uk
 * GitHub   : https://github.com/pete-rai
 * LinkedIn : https://uk.linkedin.com/in/raipete
 * NPM      : https://www.npmjs.com/~peterai
 *
 */

define ('CACHE_EXPIRY' ,  PHP_INT_MAX);  // in seconds, defaults to never
define ('CACHE_CLEAN'  ,  true       );  // auto clean on each get - if false do it manually by calling clean
define ('CACHE_PATH'   , '../cache/' );  // needs trailing slash
define ('CACHE_PREFIX' ,  'cache_'   );
define ('CACHE_EXT'    , '.txt'      );  // needs preceding dot

// --- a simple file cache

class Cache
{
    protected $expiry = CACHE_EXPIRY;
    protected $prefix = CACHE_PREFIX;

    // --- constructor

    public function __construct ($prefix = '', $expiry = 0)  // prefix with no underscore and expiry in seconds
    {
        if ($prefix) $this->prefix = $prefix;
        if ($expiry) $this->expiry = $expiry;
    }

    // --- returns the cache file name for a given hash

    protected function file ($hash)
    {
        return dirname (__FILE__).'/'.CACHE_PATH.$this->prefix.'_'.$hash.CACHE_EXT;
    }

    // --- returns whether a given cache file has expired

    protected function expired ($file)
    {
        return time () - filemtime ($file) > $this->expiry;
    }

    // --- tests the existence of a non-expired entry for a given hash

    public function has ($hash)
    {
        $file = $this->file ($hash);
        return file_exists ($file) && !$this->expired ($file);
    }

    // --- gets the contents of the cache for a given hash

    public function get ($hash)  // null return means missing or expired
    {
        if (CACHE_CLEAN)
        {
            $this->clean ();  // clean old files from the cache on every call
        }

        $body = null;

        if ($this->has ($hash))
        {
            $body = unserialize (file_get_contents ($this->file ($hash)));
        }

        return $body;
    }

    // --- puts contents into the cache for a given hash

    public function put ($hash, $body)
    {
        file_put_contents ($this->file ($hash), serialize ($body));
    }

    // --- clears the cache file for the given hash

    public function clear ($hash)
    {
        if ($this->has ($hash))
        {
            unlink ($this->file ($hash));
        }
    }

    // --- resets the cache by deleting all the files

    public function reset ()
    {
        foreach (glob ($this->file ('*')) as $file)
        {
            unlink ($file);
        }
    }

    // --- cleans the cache by deleting all the expired files

    public function clean ()
    {
        foreach (glob ($this->file ('*')) as $file)
        {
            if ($this->expired ($file))
            {
                unlink ($file);
            }
        }
    }
}

/*

// --- test code only - leave commented out once working

$expiry = 20;  // seconds
$cache  = new Cache ('test', $expiry);

// helper function to show boolean output

function show ($bool) { echo ($bool ? 'T' : 'F')."\n"; }

// cache tests

$cache->reset ();  // deletes all existing cache files

show ($cache->has ("foobar"));     // will give F

$cache->put ("foobar", ["plinth", "gusset", "catflap"]);  // makes the cache file ./cache/test_foobar.txt

show ($cache->has ("foobar"));      // will give T
var_dump ($cache->get ("foobar"));  // will output the data

sleep ($expiry + 1);

show ($cache->has ("foobar"));      // will give F - item has expired and auto clean is on
var_dump ($cache->get ("foobar"));  // will output null

$cache->put ("foobar", ["plinth", "gusset", "catflap"]);  // makes the cache file

show ($cache->has ("foobar"));      // will give T
var_dump ($cache->get ("foobar"));  // will output the data

$cache->clear ("foobar");           // deletes the cache file

show ($cache->has ("foobar"));      // will give F
var_dump ($cache->get ("foobar"));  // will output null

// end tests

$cache->reset ();  // deletes all existing cache files

*/

If you need a simpler cache without file expiry built in, you can grab one here