<?php /** * This file is part of RSS-Bridge, a PHP project capable of generating RSS and * Atom feeds for websites that don't have one. * * For the full license information, please view the UNLICENSE file distributed * with this source code. * * @package Core * @license http://unlicense.org/ UNLICENSE * @link https://github.com/rss-bridge/rss-bridge */ /** * Factory class responsible for creating cache objects from a given working * directory. * * This class is capable of: * - Locating cache classes in the specified working directory (see {@see Cache::$workingDir}) * - Creating new cache instances based on the cache's name (see {@see Cache::create()}) * * The following example illustrates the intended use for this class. * * ```PHP * require_once __DIR__ . '/rssbridge.php'; * * // Step 1: Set the working directory * Cache::setWorkingDir(__DIR__ . '/../caches/'); * * // Step 2: Create a new instance of a cache object (based on the name) * $cache = Cache::create('FileCache'); * ``` */ class Cache { /** * Holds a path to the working directory. * * Do not access this property directly! * Use {@see Cache::setWorkingDir()} and {@see Cache::getWorkingDir()} instead. * * @var string|null */ protected static $workingDir = null; /** * Throws an exception when trying to create a new instance of this class. * Use {@see Cache::create()} to create a new cache object from the working * directory. * * @throws \LogicException if called. */ public function __construct(){ throw new \LogicException('Use ' . __CLASS__ . '::create($name) to create cache objects!'); } /** * Creates a new cache object from the working directory. * * @throws \InvalidArgumentException if the requested cache name is invalid. * @throws \Exception if the requested cache file doesn't exist in the * working directory. * @param string $name Name of the cache object. * @return object The cache object. */ public static function create($name){ if(!self::isCacheName($name)) { throw new \InvalidArgumentException('Cache name invalid!'); } $filePath = self::getWorkingDir() . $name . '.php'; if(!file_exists($filePath)) { throw new \Exception('Cache file ' . $filePath . ' does not exist!'); } require_once $filePath; return new $name(); } /** * Sets the working directory. * * @param string $dir Path to a directory containing cache classes * @throws \InvalidArgumentException if $dir is not a string. * @throws \Exception if the working directory doesn't exist. * @throws \InvalidArgumentException if $dir is not a directory. * @return void */ public static function setWorkingDir($dir){ self::$workingDir = null; if(!is_string($dir)) { throw new \InvalidArgumentException('Working directory is not a valid string!'); } if(!file_exists($dir)) { throw new \Exception('Working directory does not exist!'); } if(!is_dir($dir)) { throw new \InvalidArgumentException('Working directory is not a directory!'); } self::$workingDir = realpath($dir) . '/'; } /** * Returns the working directory. * The working directory must be set with {@see Cache::setWorkingDir()}! * * @throws \LogicException if the working directory is not set. * @return string The current working directory. */ public static function getWorkingDir(){ if(is_null(self::$workingDir)) { throw new \LogicException('Working directory is not set!'); } return self::$workingDir; } /** * Returns true if the provided name is a valid cache name. * * A valid cache name starts with a capital letter ([A-Z]), followed by * zero or more alphanumeric characters or hyphen ([A-Za-z0-9-]). * * @param string $name The cache name. * @return bool true if the name is a valid cache name, false otherwise. */ public static function isCacheName($name){ return is_string($name) && preg_match('/^[A-Z][a-zA-Z0-9-]*$/', $name) === 1; } }