Add Filesystem storage backend and store photo via backend

src/Model/Storage/Filesystem.php

@@ -0,0 +1,93 @@
+<?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, $ref = null)
+	{
+		if (is_null($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 unlink($file);
+	}
+
+}