rss-bridge/lib/CacheFactory.php
logmanoriginal 2460b67886 cache: Refactor cache factory to non-static class
The cache factory can be based on the abstract factory class if it
wasn't static. This allows for higher abstraction and makes future
extensions possible. Also, not all parts of RSS-Bridge need to work
on the same instance of the factory.

References #1001
2019-06-18 19:04:19 +02:00

149 lines
4.1 KiB
PHP

<?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 CacheFactory extends FactoryAbstract {
/**
* 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 $name Name of the cache object.
* @return object|bool The cache object or false if the class is not instantiable.
*/
public function create($name){
$name = $this->sanitizeCacheName($name) . 'Cache';
if(!$this->isCacheName($name)) {
throw new \InvalidArgumentException('Cache name invalid!');
}
$filePath = $this->getWorkingDir() . $name . '.php';
if(!file_exists($filePath)) {
throw new \Exception('Cache file ' . $filePath . ' does not exist!');
}
require_once $filePath;
if((new \ReflectionClass($name))->isInstantiable()) {
return new $name();
}
return false;
}
/**
* 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 $name The cache name.
* @return bool true if the name is a valid cache name, false otherwise.
*/
public function isCacheName($name){
return is_string($name) && preg_match('/^[A-Z][a-zA-Z0-9-]*$/', $name) === 1;
}
/**
* Returns a list of cache names from the working directory.
*
* The list is cached internally to allow for successive calls.
*
* @return array List of cache names
*/
public function getCacheNames(){
static $cacheNames = array(); // Initialized on first call
if(empty($cacheNames)) {
$files = scandir($this->getWorkingDir());
if($files !== false) {
foreach($files as $file) {
if(preg_match('/^([^.]+)Cache\.php$/U', $file, $out)) {
$cacheNames[] = $out[1];
}
}
}
}
return $cacheNames;
}
/**
* Returns the sanitized cache name.
*
* The cache name can be specified in various ways:
* * The PHP file name (i.e. `FileCache.php`)
* * The PHP file name without file extension (i.e. `FileCache`)
* * The cache name (i.e. `file`)
*
* Casing is ignored (i.e. `FILE` and `fIlE` are the same).
*
* A cache file matching the given cache name must exist in the working
* directory!
*
* @param string $name The cache name
* @return string|null The sanitized cache name if the provided name is
* valid, null otherwise.
*/
protected function sanitizeCacheName($name) {
if(is_string($name)) {
// Trim trailing '.php' if exists
if(preg_match('/(.+)(?:\.php)/', $name, $matches)) {
$name = $matches[1];
}
// Trim trailing 'Cache' if exists
if(preg_match('/(.+)(?:Cache)$/i', $name, $matches)) {
$name = $matches[1];
}
// The name is valid if a corresponding file is found on disk
if(in_array(strtolower($name), array_map('strtolower', $this->getCacheNames()))) {
$index = array_search(strtolower($name), array_map('strtolower', $this->getCacheNames()));
return $this->getCacheNames()[$index];
}
Debug::log('Invalid cache name specified: "' . $name . '"!');
}
return null; // Bad parameter
}
}