Caching helper class for WordPress (can be used as a mu-plugin)

cache-helper.php

<?php
/*
 * Plugin Name: Cache Helper
 * Description: CacheHelper class provider plugin
 * Version:     1.0
 * Author:      Zachary Scott
 */

namespace zacscott;

/**
 * Caching helper which stores objects using the transients API.
 *
 * Exmaple:
 *
 * 	$cache = new CacheHelper( 'my-cache' );
 * 	$cache->set( 'my-key', $value );
 * 	echo $cache->get( 'my-key' );
 *
 * You can also cclear the cache like so:
 *
 *  $cache->clear();
 *
 * @author Zachary Scott <[email protected]>
 */
class CacheManager {

	private $group; // the cache group id

	/**
	 *
	 * @param $group - The cache group ID
	 */
	public function __construct( $group ) {
		assert( ! empty( $group ) );
		$this->group = $group;
	}

	/**
	 * Stores the given value in the cache.
	 *
	 * @param $key - the key to file the value under
	 * @param $value - the value to store
	 * @param $ttl - Time the value is cached for (default infinite)
	 */
	public function set( $key, $value, $ttl = 0 ) {
		assert( ! empty( $key ) );

		// Store the value in the transient

		$key = $this->group . '_' . $key;
		set_transient( $key, $value );

		// store the cache key, for alter lookup

		$keys = get_transient( $this->group );
		if ( ! is_array( $keys ) ) {
			$keys = array();
		}

		$keys[] = $key;
		$keys = array_unique( $keys );

		set_transient( $this->group, $keys );

	}

	/**
	 * Returns the given value from the cache.
	 *
	 * @param $key The key of the cache item to get.
	 */
	public function get( $key ) {
		assert( ! empty( $key ) );
		return get_transient( $this->group . '_ ' . $key );
	}

	/**
	 * Clears the given cache entry.
	 * If no key is given, it clears the entire cache.
	 *
	 * @param $key The cache key to clear. If not given, will clear the entire
	 * cache.
	 */
	public function clear( $key = '' ) {

		if ( empty( $key ) ) {

			$keys = get_transient( $htis->group );
			if ( ! is_array( $keys ) ) {
				$keys = array();
			}

			foreach ( $keys as $key ) {
				transient_delete( $this->group . '_' . $key );
			}

		} else {

			transient_delete( $this->group . '_' . $key );

		}

	}

}

/**
 * Copyright (C) 2014 2015,  Zachary Scott <[email protected]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */