friendica/src/Model/Storage/Filesystem.php

<?php
/**
 * @file src/Model/Storage/Filesystem.php
 * @brief Storage backend system
 */

namespace Friendica\Model\Storage;

use Friendica\Core\Config;
use Friendica\Core\L10n;
use Friendica\Core\Logger;
use Friendica\Util\Strings;

/**
 * @brief Filesystem based storage backend
 *
 * This class manage data on filesystem.
 * Base folder for storage is set in storage.filesystem_path.
 * Best would be for storage folder to be outside webserver folder, we are using a
 * folder relative to code tree root as default to ease things for users in shared hostings.
 * Each new resource gets a value as reference and is saved in a
 * folder tree stucture created from that value.
 */
class Filesystem implements IStorage
{
	// Default base folder
	const DEFAULT_BASE_FOLDER = "storage";

	private static function getBasePath()
	{
		return Config::get("storage", "filesystem_path", self::DEFAULT_BASE_FOLDER);
	}

	/**
	 * @brief Split data ref and return file path
	 * @param string  $ref  Data reference
	 * @return string
	 */
	private static function pathForRef($ref)
	{
		$base = self::getBasePath();
		$fold1 = substr($ref, 0, 2);
		$fold2 = substr($ref, 2, 2);
		$file = substr($ref, 4);

		return "{$base}/{$fold1}/{$fold2}/{$file}";
	}

	public static function get($ref)
	{
		$file = self::pathForRef($ref);
		if (!is_file($file)) {
			return "";
		}

		return file_get_contents($file);
	}

	public static function put($data, $ref = "")
	{
		if ($ref === "") {
			$ref = Strings::getRandomHex();
		}

		$file = self::pathForRef($ref);
		$path = dirname($file);

		if (!is_dir($path)) {
			if (!mkdir($path, 0770, true)) {
				Logger::log("Failed to create dirs {$path}");
				echo L10n::t("Filesystem storage failed to create '%s'. Check you write permissions.", $path);
				killme();
			}
		}

		$r = file_put_contents($file, $data);
		if ($r === FALSE) {
			Logger::log("Failed to write data to {$file}");
			echo L10n::t("Filesystem storage failed to save data to '%s'. Check your write permissions", $file);
			killme();
		}
		return $ref;
	}

	public static function delete($ref)
	{
		$file = self::pathForRef($ref);
		// return true if file doesn't exists. we want to delete it: success with zero work!
		if (!is_file($file)) { 
			return true;
		}
		return unlink($file);
	}

}