Rss-Bridge/lib/Format.php

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<?php
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/**
* 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 format objects from a given working
* directory.
*
* This class is capable of:
* - Locating format classes in the specified working directory (see {@see Format::$workingDir})
* - Creating new format instances based on the format's name (see {@see Format::create()})
*
* The following example illustrates the intended use for this class.
*
* ```PHP
* require_once __DIR__ . '/rssbridge.php';
*
* // Step 1: Set the working directory
* Format::setWorkingDir(__DIR__ . '/../formats/');
*
* // Step 2: Create a new instance of a format object (based on the name)
* $format = Format::create('Atom');
* ```
*/
class Format {
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/**
* Holds a path to the working directory.
*
* Do not access this property directly!
* Use {@see Format::setWorkingDir()} and {@see Format::getWorkingDir()} instead.
*
* @var string|null
*/
protected static $workingDir = null;
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/**
* Throws an exception when trying to create a new instance of this class.
* Use {@see Format::create()} to create a new format object from the working
* directory.
*
* @throws \LogicException if called.
*/
public function __construct(){
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throw new \LogicException('Use ' . __CLASS__ . '::create($name) to create cache objects!');
}
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/**
* Creates a new format object from the working directory.
*
* @throws \InvalidArgumentException if the requested format name is invalid.
* @throws \Exception if the requested format file doesn't exist in the
* working directory.
* @param string $name Name of the format object.
* @return object|bool The format object or false if the class is not instantiable.
*/
public static function create($name){
if(!self::isFormatName($name)) {
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throw new \InvalidArgumentException('Format name invalid!');
}
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$name = self::sanitizeFormatName($name) . 'Format';
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$pathFormat = self::getWorkingDir() . $name . '.php';
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if(!file_exists($pathFormat)) {
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throw new \Exception('Format file ' . $filePath . ' does not exist!');
}
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require_once $pathFormat;
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if((new \ReflectionClass($name))->isInstantiable()) {
return new $name();
}
return false;
}
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/**
* 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('Dir format must be a string.');
}
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if(!file_exists($dir)) {
throw new \Exception('Working directory does not exist!');
}
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if(!is_dir($dir)) {
throw new \InvalidArgumentException('Working directory is not a directory!');
}
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self::$workingDir = realpath($dir) . '/';
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}
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/**
* Returns the working directory.
* The working directory must be set with {@see Format::setWorkingDir()}!
*
* @throws \LogicException if the working directory is not set.
* @return string The current working directory.
*/
public static function getWorkingDir(){
if(is_null(self::$workingDir)) {
throw new \LogicException('Working directory is not set!');
}
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return self::$workingDir;
}
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/**
* Returns true if the provided name is a valid format name.
*
* A valid format name starts with a capital letter ([A-Z]), followed by
* zero or more alphanumeric characters or hyphen ([A-Za-z0-9-]).
*
* @param string $name The format name.
* @return bool true if the name is a valid format name, false otherwise.
*/
public static function isFormatName($name){
return is_string($name) && preg_match('/^[A-Z][a-zA-Z0-9-]*$/', $name) === 1;
}
/**
* Returns the list of format names from the working directory.
*
* The list is cached internally to allow for successive calls.
*
* @return array List of format names
*/
public static function getFormatNames(){
static $formatNames = array(); // Initialized on first call
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if(empty($formatNames)) {
$files = scandir(self::getWorkingDir());
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if($files !== false) {
foreach($files as $file) {
if(preg_match('/^([^.]+)Format\.php$/U', $file, $out)) {
$formatNames[] = $out[1];
}
}
}
}
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return $formatNames;
}
/**
* Returns the sanitized format name.
*
* The format name can be specified in various ways:
* * The PHP file name (i.e. `AtomFormat.php`)
* * The PHP file name without file extension (i.e. `AtomFormat`)
* * The format name (i.e. `Atom`)
*
* Casing is ignored (i.e. `ATOM` and `atom` are the same).
*
* A format file matching the given format name must exist in the working
* directory!
*
* @param string $name The format name
* @return string|null The sanitized format name if the provided name is
* valid, null otherwise.
*/
protected static function sanitizeFormatName($name) {
if(is_string($name)) {
// Trim trailing '.php' if exists
if(preg_match('/(.+)(?:\.php)/', $name, $matches)) {
$name = $matches[1];
}
// Trim trailing 'Format' if exists
if(preg_match('/(.+)(?:Format)/i', $name, $matches)) {
$name = $matches[1];
}
// Improve performance for correctly written format names
if(in_array($name, self::getFormatNames())) {
$index = array_search($name, self::getFormatNames());
return self::getFormatNames()[$index];
}
// The name is valid if a corresponding format file is found on disk
if(in_array(strtolower($name), array_map('strtolower', self::getFormatNames()))) {
$index = array_search(strtolower($name), array_map('strtolower', self::getFormatNames()));
return self::getFormatNames()[$index];
}
Debug::log('Invalid format name: "' . $name . '"!');
}
return null; // Bad parameter
}
}