rss-bridge/lib/BridgeFactory.php

<?php

final class BridgeFactory {

	private $folder;
	private $bridgeNames = [];
	private $whitelist = [];

	public function __construct(string $folder = PATH_LIB_BRIDGES)
	{
		$this->folder = $folder;

		// create names
		foreach(scandir($this->folder) as $file) {
			if(preg_match('/^([^.]+)Bridge\.php$/U', $file, $m)) {
				$this->bridgeNames[] = $m[1];
			}
		}

		// create whitelist
		if (file_exists(WHITELIST)) {
			$contents = trim(file_get_contents(WHITELIST));
		} elseif (file_exists(WHITELIST_DEFAULT)) {
			$contents = trim(file_get_contents(WHITELIST_DEFAULT));
		} else {
			$contents = '';
		}
		if ($contents === '*') { // Whitelist all bridges
			$this->whitelist = $this->getBridgeNames();
		} else {
			foreach (explode("\n", $contents) as $bridgeName) {
				$this->whitelist[] = $this->sanitizeBridgeName($bridgeName);
			}
		}
	}

	public function create(string $name): BridgeInterface
	{
		if(preg_match('/^[A-Z][a-zA-Z0-9-]*$/', $name)) {
			$className = sprintf('%sBridge', $this->sanitizeBridgeName($name));
			return new $className();
		}
		throw new \InvalidArgumentException('Bridge name invalid!');
	}

	public function getBridgeNames(): array
	{
		return $this->bridgeNames;
	}

	public function isWhitelisted($name): bool
	{
		return in_array($this->sanitizeBridgeName($name), $this->whitelist);
	}

	private function sanitizeBridgeName($name) {

		if(!is_string($name)) {
			return null;
		}

		// Trim trailing '.php' if exists
		if (preg_match('/(.+)(?:\.php)/', $name, $matches)) {
			$name = $matches[1];
		}

		// Trim trailing 'Bridge' if exists
		if (preg_match('/(.+)(?:Bridge)/i', $name, $matches)) {
			$name = $matches[1];
		}

		// Improve performance for correctly written bridge names
		if (in_array($name, $this->getBridgeNames())) {
			$index = array_search($name, $this->getBridgeNames());
			return $this->getBridgeNames()[$index];
		}

		// The name is valid if a corresponding bridge file is found on disk
		if (in_array(strtolower($name), array_map('strtolower', $this->getBridgeNames()))) {
			$index = array_search(strtolower($name), array_map('strtolower', $this->getBridgeNames()));
			return $this->getBridgeNames()[$index];
		}

		Debug::log('Invalid bridge name specified: "' . $name . '"!');
		return null;
	}
}