3) Introducing ConfigFactory

src/Util/BasePath.php

@@ -0,0 +1,93 @@
+<?php
+
+namespace Friendica\Util;
+
+use Friendica\Core;
+
+class BasePath
+{
+	/**
+	 * @brief Returns the base filesystem path of the App
+	 *
+	 * It first checks for the internal variable, then for DOCUMENT_ROOT and
+	 * finally for PWD
+	 *
+	 * @param string|null $basepath
+	 *
+	 * @return string
+	 *
+	 * @throws \Exception if directory isn't usable
+	 */
+	public static function create($basepath)
+	{
+		if (!$basepath && !empty($_SERVER['DOCUMENT_ROOT'])) {
+			$basepath = $_SERVER['DOCUMENT_ROOT'];
+		}
+
+		if (!$basepath && !empty($_SERVER['PWD'])) {
+			$basepath = $_SERVER['PWD'];
+		}
+
+		return self::getRealPath($basepath);
+	}
+
+	/**
+	 * @brief Returns a normalized file path
+	 *
+	 * This is a wrapper for the "realpath" function.
+	 * That function cannot detect the real path when some folders aren't readable.
+	 * Since this could happen with some hosters we need to handle this.
+	 *
+	 * @param string $path The path that is about to be normalized
+	 * @return string normalized path - when possible
+	 */
+	public static function getRealPath($path)
+	{
+		$normalized = realpath($path);
+
+		if (!is_bool($normalized)) {
+			return $normalized;
+		} else {
+			return $path;
+		}
+	}
+
+
+	/**
+	 * @brief Checks if a given directory is usable for the system
+	 *
+	 * @param      $directory
+	 * @param bool $check_writable
+	 *
+	 * @return boolean the directory is usable
+	 */
+	public static function isDirectoryUsable($directory, $check_writable = true)
+	{
+		if ($directory == '') {
+			Core\Logger::log('Directory is empty. This shouldn\'t happen.', Core\Logger::DEBUG);
+			return false;
+		}
+
+		if (!file_exists($directory)) {
+			Core\Logger::log('Path "' . $directory . '" does not exist for user ' . Core\System::getUser(), Core\Logger::DEBUG);
+			return false;
+		}
+
+		if (is_file($directory)) {
+			Core\Logger::log('Path "' . $directory . '" is a file for user ' . Core\System::getUser(), Core\Logger::DEBUG);
+			return false;
+		}
+
+		if (!is_dir($directory)) {
+			Core\Logger::log('Path "' . $directory . '" is not a directory for user ' . Core\System::getUser(), Core\Logger::DEBUG);
+			return false;
+		}
+
+		if ($check_writable && !is_writable($directory)) {
+			Core\Logger::log('Path "' . $directory . '" is not writable for user ' . Core\System::getUser(), Core\Logger::DEBUG);
+			return false;
+		}
+
+		return true;
+	}
+}