diff --git a/src/_h5ai/server/php/inc/Api.php b/src/_h5ai/server/php/inc/Api.php
index fe063c64..b9f855b4 100644
--- a/src/_h5ai/server/php/inc/Api.php
+++ b/src/_h5ai/server/php/inc/Api.php
@@ -16,7 +16,7 @@ class Api {
 
 		$options = $this->app->get_options();
 
-		list($action) = use_request_params(array("action"));
+		$action = use_request_param("action");
 
 		if ($action === "get") {
 
@@ -24,50 +24,54 @@ class Api {
 
 			if (has_request_param("options")) {
 
-				use_request_params("options");
+				use_request_param("options");
 				$response["options"] = $this->app->get_options();
 			}
 
 			if (has_request_param("types")) {
 
-				use_request_params("types");
+				use_request_param("types");
 				$response["types"] = $this->app->get_types();
 			}
 
 			if (has_request_param("langs")) {
 
-				use_request_params("langs");
+				use_request_param("langs");
 				$response["langs"] = $this->app->get_l10n_list();
 			}
 
 			if (has_request_param("l10n")) {
 
-				list($iso_codes) = use_request_params("l10nCodes", "l10n");
+				use_request_param("l10n");
+				$iso_codes = use_request_param("l10nCodes");
 				$iso_codes = explode(":", $iso_codes);
 				$response["l10n"] = $this->app->get_l10n($iso_codes);
 			}
 
 			if (has_request_param("checks")) {
 
-				use_request_params("checks");
+				use_request_param("checks");
 				$response["checks"] = $this->app->get_server_checks();
 			}
 
 			if (has_request_param("server")) {
 
-				use_request_params("server");
+				use_request_param("server");
 				$response["server"] = $this->app->get_server_details();
 			}
 
 			if (has_request_param("custom")) {
 
-				list($abs_href) = use_optional_request_params("customHref", "custom");
+				use_request_param("custom");
+				$abs_href = use_request_param("customHref", null);
 				$response["custom"] = $this->app->get_customizations($abs_href);
 			}
 
 			if (has_request_param("items")) {
 
-				list($abs_href, $what) = use_optional_request_params("itemsHref", "itemsWhat", "items");
+				use_request_param("items");
+				$abs_href = use_request_param("itemsHref", null);
+				$what = use_request_param("itemsWhat", null);
 				$what = is_numeric($what) ? intval($what, 10) : 1;
 				$response["items"] = $this->app->get_items($abs_href, $what);
 			}
@@ -91,15 +95,19 @@ class Api {
 				json_fail(2, "thumbnails not supported");
 			}
 
-			list($type, $src_abs_href, $mode, $width, $height) = use_request_params(array("type", "href", "mode", "width", "height"));
+			$type = use_request_param("type");
+			$src_url = use_request_param("href");
+			$mode = use_request_param("mode");
+			$width = use_request_param("width");
+			$height = use_request_param("height");
 
 			$thumb = new Thumb($this->app);
-			$thumb_href = $thumb->thumb($type, $src_abs_href, $mode, $width, $height);
-			if ($thumb_href === null) {
+			$thumb_url = $thumb->thumb($type, $src_url, $mode, $width, $height);
+			if ($thumb_url === null) {
 				json_fail(3, "thumbnail creation failed");
 			}
 
-			json_exit(array("absHref" => $thumb_href));
+			json_exit(array("absHref" => $thumb_url));
 		}
 
 
@@ -107,7 +115,9 @@ class Api {
 
 			json_fail(1, "downloads disabled", !$options["download"]["enabled"]);
 
-			list($as, $type, $hrefs) = use_request_params(array("as", "type", "hrefs"));
+			$as = use_request_param("as");
+			$type = use_request_param("type");
+			$hrefs = use_request_param("hrefs");
 
 			normalized_require_once("Archive.php");
 			$archive = new Archive($this->app);
@@ -129,7 +139,7 @@ class Api {
 
 		else if ($action === "upload") {
 
-			list($href) = use_request_params(array("href"));
+			$href = use_request_param("href");
 
 			json_fail(1, "wrong HTTP method", strtolower($_SERVER["REQUEST_METHOD"]) !== "post");
 			json_fail(2, "something went wrong", !array_key_exists("userfile", $_FILES));
@@ -139,10 +149,10 @@ class Api {
 			json_fail(3, "something went wrong [" . $userfile["error"] . "]", $userfile["error"] !== 0);
 			json_fail(4, "folders not supported", file_get_contents($userfile["tmp_name"]) === "null");
 
-			$upload_dir = $this->app->get_abs_path($href);
+			$upload_dir = $this->app->to_path($href);
 			$code = $this->app->get_http_code($href);
 
-			json_fail(5, "upload dir no h5ai folder or ignored", $code !== App::$MAGIC_SEQUENCE || $this->app->is_ignored($upload_dir));
+			json_fail(5, "upload dir no h5ai folder or ignored", $code !== MAGIC_SEQUENCE || $this->app->is_ignored($upload_dir));
 
 			$dest = $upload_dir . "/" . utf8_encode($userfile["name"]);
 
@@ -157,7 +167,7 @@ class Api {
 
 			json_fail(1, "deletion disabled", !$options["delete"]["enabled"]);
 
-			list($hrefs) = use_request_params(array("hrefs"));
+			$hrefs = use_request_param("hrefs");
 
 			$hrefs = explode("|:|", trim($hrefs));
 			$errors = array();
@@ -169,9 +179,9 @@ class Api {
 
 				$code = $this->app->get_http_code($d);
 
-				if ($code == App::$MAGIC_SEQUENCE && !$this->app->is_ignored($n)) {
+				if ($code == MAGIC_SEQUENCE && !$this->app->is_ignored($n)) {
 
-					$abs_path = $this->app->get_abs_path($href);
+					$abs_path = $this->app->to_path($href);
 
 					if (!unlink($abs_path)) {
 						$errors[] = $href;
@@ -191,16 +201,17 @@ class Api {
 
 			json_fail(1, "renaming disabled", !$options["rename"]["enabled"]);
 
-			list($href, $name) = use_request_params(array("href", "name"));
+			$href = use_request_param("href");
+			$name = use_request_param("name");
 
 			$d = normalize_path(dirname($href), true);
 			$n = basename($href);
 
 			$code = $this->app->get_http_code($d);
 
-			if ($code == App::$MAGIC_SEQUENCE && !$this->app->is_ignored($n)) {
+			if ($code == MAGIC_SEQUENCE && !$this->app->is_ignored($n)) {
 
-				$abs_path = $this->app->get_abs_path($href);
+				$abs_path = $this->app->to_path($href);
 				$folder = normalize_path(dirname($abs_path));
 
 				if (!rename($abs_path, $folder . "/" . $name)) {
diff --git a/src/_h5ai/server/php/inc/App.php b/src/_h5ai/server/php/inc/App.php
index 11b69732..b6af8c74 100644
--- a/src/_h5ai/server/php/inc/App.php
+++ b/src/_h5ai/server/php/inc/App.php
@@ -2,110 +2,28 @@
 
 class App {
 
-	public static $MAGIC_SEQUENCE = "={{pkg.name}}=";
-	public static $FILE_PREFIX = "_{{pkg.name}}";
-
-	private static $MIN_PHP_VERSION = "5.3.0";
 	private static $RE_DELIMITER = "|";
-	private static $CACHE_DIR = "cache";
 
 
-	private $is_win_os, $is_supported_php,
-			$server_name, $server_version,
-			$app_abs_path, $root_abs_path,
-			$app_abs_href, $root_abs_href,
-			$abs_href, $abs_path,
-			$options;
+	private $options;
 
 
-	public static function from_env() {
+	public function __construct() {
 
-		$server_name = null;
-		$server_version = null;
-		if (preg_match("#^(.*?)/(.*?)(?: |$)#", strtolower(getenv("SERVER_SOFTWARE")), $matches)) {
-			$server_name = $matches[1];
-			$server_version = $matches[2];
-		}
-
-		$app_abs_path = normalize_path(dirname(dirname(dirname(dirname(__FILE__)))));
-
-		$script_name = getenv("SCRIPT_NAME");
-		if ($server_name === "lighttpd") {
-			$script_name = preg_replace("#^.*//#", "/", $script_name);
-		}
-		$app_abs_href = dirname(dirname(dirname($script_name)));
-
-		$url_parts = parse_url(getenv("REQUEST_URI"));
-		$abs_href = $url_parts["path"];
-
-		return new App($server_name, $server_version, $app_abs_path, $app_abs_href, $abs_href);
+		$this->options = load_commented_json(APP_PATH . "/conf/options.json");
 	}
 
 
-	public function __construct($server_name, $server_version, $app_abs_path, $app_abs_href, $abs_href) {
+	public function get_options() {
 
-		$this->is_win_os = strtolower(substr(PHP_OS, 0, 3)) === "win";
-		$this->is_supported_php = version_compare(PHP_VERSION, App::$MIN_PHP_VERSION) >= 0;
-
-		$this->server_name = strtolower($server_name);
-		$this->server_version = strtolower($server_version);
-
-		$this->app_abs_path = normalize_path($app_abs_path);
-		$this->root_abs_path = normalize_path(dirname($this->app_abs_path));
-
-		$this->app_abs_href = normalize_path($app_abs_href, true);
-		$this->root_abs_href = normalize_path(dirname($this->app_abs_href), true);
-
-		$this->abs_href = normalize_path($abs_href, true);
-		$this->abs_path = $this->get_abs_path($this->abs_href);
-
-		// echo("<pre>");
-		// var_dump($this);
-		// exit();
-
-		$this->options = load_commented_json($this->app_abs_path . "/conf/options.json");
+		return $this->options;
 	}
 
 
-	public function get_root_abs_path() {
+	public function to_url($path, $trailing_slash = true) {
 
-		return $this->root_abs_path;
-	}
-
-
-	public function get_root_abs_href() {
-
-		return $this->root_abs_href;
-	}
-
-
-	public function get_app_abs_href() {
-
-		return $this->app_abs_href;
-	}
-
-
-	public function get_cache_abs_path() {
-
-		return $this->app_abs_path . '/' . App::$CACHE_DIR;
-	}
-
-
-	public function get_cache_abs_href() {
-
-		return $this->app_abs_href . App::$CACHE_DIR . '/';
-	}
-
-
-	public function get_abs_href($abs_path = null, $trailing_slash = true) {
-
-		if ($abs_path === null) {
-			return $this->abs_href;
-		}
-
-		$abs_path = substr($abs_path, strlen($this->root_abs_path));
-
-		$parts = explode("/", $abs_path);
+		$rel_path = substr($path, strlen(ROOT_PATH));
+		$parts = explode("/", $rel_path);
 		$encoded_parts = array();
 		foreach ($parts as $part) {
 			if ($part) {
@@ -113,19 +31,14 @@ class App {
 			}
 		}
 
-		return normalize_path($this->root_abs_href . implode("/", $encoded_parts), $trailing_slash);
+		return normalize_path(ROOT_URL . implode("/", $encoded_parts), $trailing_slash);
 	}
 
 
-	public function get_abs_path($abs_href = null) {
+	public function to_path($url) {
 
-		if ($abs_href === null) {
-			return $this->abs_path;
-		}
-
-		$abs_href = substr($abs_href, strlen($this->root_abs_href));
-
-		return normalize_path($this->root_abs_path . "/" . rawurldecode($abs_href));
+		$rel_url = substr($url, strlen(ROOT_URL));
+		return normalize_path(ROOT_PATH . "/" . rawurldecode($rel_url));
 	}
 
 
@@ -149,71 +62,64 @@ class App {
 
 	public function read_dir($path) {
 
-		$content = array();
+		$names = array();
 		if (is_dir($path)) {
 			if ($dir = opendir($path)) {
-				while (($file = readdir($dir)) !== false) {
-					if (!$this->is_ignored($file) && !$this->is_ignored($this->get_abs_href($path) . $file)) {
-						$content[] = $file;
+				while (($name = readdir($dir)) !== false) {
+					if (!$this->is_ignored($name) && !$this->is_ignored($this->to_url($path) . $name)) {
+						$names[] = $name;
 					}
 				}
 				closedir($dir);
 			}
 		}
-		return $content;
+		return $names;
 	}
 
 
-	public function get_options() {
+	public function get_http_code($url) {
 
-		return $this->options;
-	}
+		$path = $this->to_path($url);
 
-
-	public function get_http_code($abs_href) {
-
-		$abs_path = $this->get_abs_path($abs_href);
-
-		if (!is_dir($abs_path) || strpos($abs_path, '../') || strpos($abs_path, '/..') || $abs_path == '..') {
+		if (!is_dir($path) || strpos($path, '../') || strpos($path, '/..') || $path == '..') {
 			return 500;
 		}
 
 		foreach ($this->options["view"]["indexFiles"] as $if) {
-			if (file_exists($abs_path . "/" . $if)) {
+			if (file_exists($path . "/" . $if)) {
 				return 200;
 			}
 		}
 
-		$p = $abs_path;
-		while ($p !== $this->root_abs_path) {
-			if (@is_dir($p . "/_h5ai/server")) {
+		while ($path !== ROOT_PATH) {
+			if (@is_dir($path . "/_h5ai/server")) {
 				return 200;
 			}
-			$pp = normalize_path(dirname($p));
-			if ($pp === $p) {
+			$parent_path = normalize_path(dirname($path));
+			if ($parent_path === $path) {
 				return 200;
 			}
-			$p = $pp;
+			$path = $parent_path;
 		}
-		return App::$MAGIC_SEQUENCE;
+		return MAGIC_SEQUENCE;
 	}
 
 
 	public function get_generic_json() {
 
-		return json_encode(array("items" => $this->get_items($this->abs_href, 1))) . "\n";
+		return json_encode(array("items" => $this->get_items(CURRENT_URL, 1))) . "\n";
 	}
 
 
-	public function get_items($abs_href, $what) {
+	public function get_items($url, $what) {
 
-		$code = $this->get_http_code($abs_href);
-		if ($code != App::$MAGIC_SEQUENCE) {
+		$code = $this->get_http_code($url);
+		if ($code !== MAGIC_SEQUENCE) {
 			return array();
 		}
 
 		$cache = array();
-		$folder = Item::get($this, $this->get_abs_path($abs_href), $cache);
+		$folder = Item::get($this, $this->to_path($url), $cache);
 
 		// add content of subfolders
 		if ($what >= 2 && $folder !== null) {
@@ -242,7 +148,7 @@ class App {
 	public function get_fallback() {
 
 		$cache = array();
-		$folder = Item::get($this, $this->abs_path, $cache);
+		$folder = Item::get($this, CURRENT_PATH, $cache);
 		$items = $folder->get_content($cache);
 		uasort($items, array("Item", "cmp"));
 
@@ -257,7 +163,7 @@ class App {
 
 		if ($folder->get_parent($cache)) {
 			$html .= "<tr>";
-			$html .= "<td><img src='" . $this->app_abs_href . "client/icons/96/folder-parent.png' alt='folder-parent'/></td>";
+			$html .= "<td><img src='" . APP_URL . "client/icons/96/folder-parent.png' alt='folder-parent'/></td>";
 			$html .= "<td><a href='..'>Parent Directory</a></td>";
 			$html .= "<td></td>";
 			$html .= "<td></td>";
@@ -268,8 +174,8 @@ class App {
 			$type = $item->is_folder ? "folder" : "default";
 
 			$html .= "<tr>";
-			$html .= "<td><img src='" . $this->app_abs_href . "client/icons/96/" . $type . ".png' alt='" . $type . "'/></td>";
-			$html .= "<td><a href='" . $item->abs_href . "'>" . basename($item->abs_path) . "</a></td>";
+			$html .= "<td><img src='" . APP_URL . "client/icons/96/" . $type . ".png' alt='" . $type . "'/></td>";
+			$html .= "<td><a href='" . $item->url . "'>" . basename($item->path) . "</a></td>";
 			$html .= "<td>" . date("Y-m-d H:i", $item->date) . "</td>";
 			$html .= "<td>" . ($item->size !== null ? intval($item->size / 1000) . " KB" : "" ) . "</td>";
 			$html .= "</tr>";
@@ -283,19 +189,19 @@ class App {
 
 	public function get_types() {
 
-		return load_commented_json($this->app_abs_path . "/conf/types.json");
+		return load_commented_json(APP_PATH . "/conf/types.json");
 	}
 
 
 	public function get_l10n_list() {
 
 		$langs = array();
-		$l10nDir = $this->app_abs_path . "/conf/l10n";
-		if (is_dir($l10nDir)) {
-			if ($dir = opendir($l10nDir)) {
+		$l10n_path = APP_PATH . "/conf/l10n";
+		if (is_dir($l10n_path)) {
+			if ($dir = opendir($l10n_path)) {
 				while (($file = readdir($dir)) !== false) {
 					if (ends_with($file, ".json")) {
-						$translations = load_commented_json($l10nDir . "/" . $file);
+						$translations = load_commented_json($l10n_path . "/" . $file);
 						$langs[basename($file, ".json")] = $translations["lang"];
 					}
 				}
@@ -313,16 +219,16 @@ class App {
 			$iso_codes = func_get_args();
 		}
 
-		$result = array();
+		$results = array();
 		foreach ($iso_codes as $iso_code) {
 			if ($iso_code !== "") {
-				$file = $this->app_abs_path . "/conf/l10n/" . $iso_code . ".json";
-				$result[$iso_code] = load_commented_json($file);
-				$result[$iso_code]["isoCode"] = $iso_code;
+				$file = APP_PATH . "/conf/l10n/" . $iso_code . ".json";
+				$results[$iso_code] = load_commented_json($file);
+				$results[$iso_code]["isoCode"] = $iso_code;
 			}
 		}
 
-		return $result;
+		return $results;
 	}
 
 
@@ -330,35 +236,35 @@ class App {
 
 		$results = array();
 
-		$results["path_index"] = $this->app_abs_href . "server/php/index.php";
-		$results["path_cache_writable"] = @is_writable($this->get_cache_abs_path());
+		$results["path_index"] = INDEX_URL;
+		$results["path_cache_writable"] = @is_writable(CACHE_PATH);
 		$results["php_version"] = PHP_VERSION;
-		$results["php_version_supported"] = $this->is_supported_php;
+		$results["php_version_supported"] = IS_PHP_VERSION_SUPPORTED;
 		$results["php_exif"] = function_exists("exif_thumbnail");
 
-		$gd = false;
+		$php_jpg = false;
 		if (function_exists("gd_info")) {
-			$gdinfo = gd_info();
-			$gd = array_key_exists("JPG Support", $gdinfo) && $gdinfo["JPG Support"] || array_key_exists("JPEG Support", $gdinfo) && $gdinfo["JPEG Support"];
+			$infos = gd_info();
+			$php_jpg = array_key_exists("JPG Support", $infos) && $infos["JPG Support"] || array_key_exists("JPEG Support", $infos) && $infos["JPEG Support"];
 		}
-		$results["php_jpg"] = $gd;
+		$results["php_jpg"] = $php_jpg;
 
-		$check_cmd = $this->is_win_os ? "which" : "command -v";
-		foreach (array("tar", "zip", "convert", "ffmpeg", "avconv", "du") as $c) {
-			$results["cmd_" . $c] = @preg_match("#" . $c . "(.exe)?$#i", exec_cmd($check_cmd . " " . $c)) > 0;
+		$check_cmd = IS_WIN_OS ? "which" : "command -v";
+		foreach (array("tar", "zip", "convert", "ffmpeg", "avconv", "du") as $cmd) {
+			$results["cmd_" . $cmd] = @preg_match("#" . $cmd . "(.exe)?$#i", exec_cmd($check_cmd . " " . $cmd)) > 0;
 		}
 		$results["cmd_ffmpeg_or_avconv"] = $results["cmd_ffmpeg"] || $results["cmd_avconv"];
 
-		$results["is_win_os"] = $this->is_win_os;
-		$results["is_supported_php"] = $this->is_supported_php;
-		$results["server_name"] = $this->server_name;
-		$results["server_version"] = $this->server_version;
-		$results["app_abs_path"] = $this->app_abs_path;
-		$results["root_abs_path"] = $this->root_abs_path;
-		$results["app_abs_href"] = $this->app_abs_href;
-		$results["root_abs_href"] = $this->root_abs_href;
-		$results["abs_href"] = $this->abs_href;
-		$results["abs_path"] = $this->abs_path;
+		$results["is_win_os"] = IS_WIN_OS;
+		$results["is_supported_php"] = IS_PHP_VERSION_SUPPORTED;
+		$results["server_name"] = SERVER_NAME;
+		$results["server_version"] = SERVER_VERSION;
+		$results["app_url"] = APP_URL;
+		$results["app_path"] = APP_PATH;
+		$results["root_url"] = ROOT_URL;
+		$results["root_path"] = ROOT_PATH;
+		$results["current_url"] = CURRENT_URL;
+		$results["current_path"] = CURRENT_PATH;
 		$results["options"] = $this->options;
 
 		return $results;
@@ -370,13 +276,13 @@ class App {
 		return array(
 			"backend" => "php",
 			"api" => true,
-			"name" => $this->server_name,
-			"version" => $this->server_version
+			"name" => SERVER_NAME,
+			"version" => SERVER_VERSION
 		);
 	}
 
 
-	public function get_customizations($abs_href) {
+	public function get_customizations($url) {
 
 		if (!$this->options["custom"]["enabled"]) {
 			return array(
@@ -385,32 +291,32 @@ class App {
 			);
 		}
 
-		$abs_path = $this->get_abs_path($abs_href);
-		$file = $abs_path . "/" . App::$FILE_PREFIX . ".header.html";
+		$path = $this->to_path($url);
+
+		$file = $path . "/" . FILE_PREFIX . ".header.html";
 		$header = is_readable($file) ? file_get_contents($file) : null;
-		$file = $abs_path . "/" . App::$FILE_PREFIX . ".footer.html";
+		$file = $path . "/" . FILE_PREFIX . ".footer.html";
 		$footer = is_readable($file) ? file_get_contents($file) : null;
 
-		$p = $abs_path;
 		while ($header === null || $footer === null) {
 
 			if ($header === null) {
-				$file = $p . "/" . App::$FILE_PREFIX . ".headers.html";
+				$file = $path . "/" . FILE_PREFIX . ".headers.html";
 				$header = is_readable($file) ? file_get_contents($file) : null;
 			}
 			if ($footer === null) {
-				$file = $p . "/" . App::$FILE_PREFIX . ".footers.html";
+				$file = $path . "/" . FILE_PREFIX . ".footers.html";
 				$footer = is_readable($file) ? file_get_contents($file) : null;
 			}
 
-			if ($p === $this->root_abs_path) {
+			if ($path === ROOT_PATH) {
 				break;
 			}
-			$pp = normalize_path(dirname($p));
-			if ($pp === $p) {
+			$parent_path = normalize_path(dirname($path));
+			if ($parent_path === $path) {
 				break;
 			}
-			$p = $pp;
+			$path = $parent_path;
 		}
 
 		return array(
diff --git a/src/_h5ai/server/php/inc/Archive.php b/src/_h5ai/server/php/inc/Archive.php
index 34d8f9fc..3f15b185 100644
--- a/src/_h5ai/server/php/inc/Archive.php
+++ b/src/_h5ai/server/php/inc/Archive.php
@@ -15,12 +15,12 @@ class Archive {
 	}
 
 
-	public function output($type, $hrefs) {
+	public function output($type, $urls) {
 
 		$this->dirs = array();
 		$this->files = array();
 
-		$this->add_hrefs($hrefs);
+		$this->add_hrefs($urls);
 
 		if (count($this->dirs) === 0 && count($this->files) === 0) {
 			return 500;
@@ -44,7 +44,7 @@ class Archive {
 
 	private function shell_cmd($cmd) {
 
-		$cmd = str_replace("[ROOTDIR]", escapeshellarg($this->app->get_abs_path()), $cmd);
+		$cmd = str_replace("[ROOTDIR]", escapeshellarg(CURRENT_PATH), $cmd);
 		$cmd = str_replace("[DIRS]", count($this->dirs) ? implode(" ", array_map("escapeshellarg", $this->dirs)) : "", $cmd);
 		$cmd = str_replace("[FILES]", count($this->files) ? implode(" ", array_map("escapeshellarg", $this->files)) : "", $cmd);
 		try {
@@ -133,27 +133,27 @@ class Archive {
 		if ($fd = fopen($file, 'rb')) {
 			while (!feof($fd)) {
 				print fread($fd, Archive::$SEGMENT_SIZE);
-				ob_flush();
-				flush();
+				@ob_flush();
+				@flush();
 			}
 			fclose($fd);
 		}
 	}
 
 
-	private function add_hrefs($hrefs) {
+	private function add_hrefs($urls) {
 
-		foreach ($hrefs as $href) {
+		foreach ($urls as $href) {
 
 			$d = normalize_path(dirname($href), true);
 			$n = basename($href);
 
 			$code = $this->app->get_http_code($d);
 
-			if ($code == App::$MAGIC_SEQUENCE && !$this->app->is_ignored($n)) {
+			if ($code === MAGIC_SEQUENCE && !$this->app->is_ignored($n)) {
 
-				$real_file = $this->app->get_abs_path($href);
-				$archived_file = preg_replace("!^" . preg_quote(normalize_path($this->app->get_abs_path(), true)) . "!", "", $real_file);
+				$real_file = $this->app->to_path($href);
+				$archived_file = preg_replace("!^" . preg_quote(normalize_path(CURRENT_PATH, true)) . "!", "", $real_file);
 
 				if (is_dir($real_file)) {
 					$this->add_dir($real_file, $archived_file);
@@ -175,9 +175,9 @@ class Archive {
 
 	private function add_dir($real_dir, $archived_dir) {
 
-		$code = $this->app->get_http_code($this->app->get_abs_href($real_dir));
+		$code = $this->app->get_http_code($this->app->to_url($real_dir));
 
-		if ($code == App::$MAGIC_SEQUENCE) {
+		if ($code === MAGIC_SEQUENCE) {
 			$this->dirs[] = $archived_dir;
 
 			$files = $this->app->read_dir($real_dir);
diff --git a/src/_h5ai/server/php/inc/Item.php b/src/_h5ai/server/php/inc/Item.php
index cf0adaf8..531508c7 100644
--- a/src/_h5ai/server/php/inc/Item.php
+++ b/src/_h5ai/server/php/inc/Item.php
@@ -13,55 +13,55 @@ class Item {
 			return 1;
 		}
 
-		return strcasecmp($item1->abs_path, $item2->abs_path);
+		return strcasecmp($item1->path, $item2->path);
 	}
 
-	public static function get($app, $abs_path, &$cache) {
+	public static function get($app, $path, &$cache) {
 
-		if (!starts_with($abs_path, $app->get_root_abs_path())) {
-			error_log("ILLEGAL REQUEST: " . $abs_path . ", " . $app->get_root_abs_path());
+		if (!starts_with($path, ROOT_PATH)) {
+			error_log("ILLEGAL REQUEST: " . $path . ", " . ROOT_PATH);
 			return null;
 		}
 
-		if (is_array($cache) && array_key_exists($abs_path, $cache)) {
-			return $cache[$abs_path];
+		if (is_array($cache) && array_key_exists($path, $cache)) {
+			return $cache[$path];
 		}
 
-		$item = new Item($app, $abs_path);
+		$item = new Item($app, $path);
 
 		if (is_array($cache)) {
-			$cache[$abs_path] = $item;
+			$cache[$path] = $item;
 		}
 		return $item;
 	}
 
 
 	public $app,
-			$abs_path, $abs_href,
+			$path, $url,
 			$date, $size,
 			$is_folder,
 			$is_content_fetched;
 
 
-	private function __construct($app, $abs_path) {
+	private function __construct($app, $path) {
 
 		$this->app = $app;
 
-		$this->abs_path = normalize_path($abs_path);
-		$this->is_folder = is_dir($this->abs_path);
-		$this->abs_href = $this->app->get_abs_href($abs_path, $this->is_folder);
+		$this->path = normalize_path($path, false);
+		$this->is_folder = is_dir($this->path);
+		$this->url = $this->app->to_url($path, $this->is_folder);
 
-		$this->date = @filemtime($this->abs_path);
+		$this->date = @filemtime($this->path);
 
 		if ($this->is_folder) {
 			$this->size = null;
 			$options = $app->get_options();
 			if ($options["foldersize"]["enabled"]) {
-				$cmd = str_replace("[DIR]", escapeshellarg($this->abs_path), Item::$FOLDER_SIZE_CMD);
-				$this->size = intval(preg_replace("/\s.*$/", "", exec_cmd($cmd)), 10) * 1024;
+				$cmd = str_replace("[DIR]", escapeshellarg($this->path), Item::$FOLDER_SIZE_CMD);
+				$this->size = intval(preg_replace("#\s.*$#", "", exec_cmd($cmd)), 10) * 1024;
 			}
 		} else {
-			$this->size = @filesize($this->abs_path);
+			$this->size = @filesize($this->path);
 		}
 
 		$this->is_content_fetched = false;
@@ -71,13 +71,13 @@ class Item {
 	public function to_json_object() {
 
 		$obj = array(
-			"absHref" => $this->abs_href,
+			"absHref" => $this->url,
 			"time" => $this->date * 1000, // seconds (PHP) to milliseconds (JavaScript)
 			"size" => $this->size
 		);
 
 		if ($this->is_folder) {
-			$obj["status"] = $this->app->get_http_code($this->abs_href);
+			$obj["status"] = $this->app->get_http_code($this->url);
 			$obj["content"] = $this->is_content_fetched;
 		}
 
@@ -87,9 +87,9 @@ class Item {
 
 	public function get_parent(&$cache) {
 
-		$parent_abs_path = normalize_path(dirname($this->abs_path));
-		if ($parent_abs_path !== $this->abs_path && starts_with($parent_abs_path, $this->app->get_root_abs_path())) {
-			return Item::get($this->app, $parent_abs_path, $cache);
+		$parent_path = normalize_path(dirname($this->path), false);
+		if ($parent_path !== $this->path && starts_with($parent_path, ROOT_PATH)) {
+			return Item::get($this->app, $parent_path, $cache);
 		}
 		return null;
 	}
@@ -97,21 +97,21 @@ class Item {
 
 	public function get_content(&$cache) {
 
-		$content = array();
+		$items = array();
 
-		if ($this->app->get_http_code($this->abs_href) !== App::$MAGIC_SEQUENCE) {
-			return $content;
+		if ($this->app->get_http_code($this->url) !== MAGIC_SEQUENCE) {
+			return $items;
 		}
 
-		$files = $this->app->read_dir($this->abs_path);
+		$files = $this->app->read_dir($this->path);
 		foreach ($files as $file) {
-			$item = Item::get($this->app, $this->abs_path . "/" . $file, $cache);
-			$content[$item->abs_path] = $item;
+			$item = Item::get($this->app, $this->path . "/" . $file, $cache);
+			$items[$item->path] = $item;
 		}
 
 		$this->is_content_fetched = true;
 
-		return $content;
+		return $items;
 	}
 }
 
diff --git a/src/_h5ai/server/php/inc/Thumb.php b/src/_h5ai/server/php/inc/Thumb.php
index f982cb7f..5def0a58 100644
--- a/src/_h5ai/server/php/inc/Thumb.php
+++ b/src/_h5ai/server/php/inc/Thumb.php
@@ -21,33 +21,33 @@ class Thumb {
 	public function __construct($app) {
 
 		$this->app = $app;
-		$this->thumbs_path = $this->app->get_cache_abs_path() . "/" . Thumb::$THUMB_CACHE;
-		$this->thumbs_href = $this->app->get_cache_abs_href() . Thumb::$THUMB_CACHE;
+		$this->thumbs_path = CACHE_PATH . "/" . Thumb::$THUMB_CACHE;
+		$this->thumbs_href = CACHE_URL . Thumb::$THUMB_CACHE;
 	}
 
 
-	public function thumb($type, $source_abs_href, $mode, $width, $height) {
+	public function thumb($type, $source_url, $mode, $width, $height) {
 
-		$source_abs_path = $this->app->get_abs_path($source_abs_href);
+		$source_path = $this->app->to_path($source_url);
 
 		if ($type === "img") {
-			$capture_abs_path = $source_abs_path;
+			$capture_path = $source_path;
 		} else if ($type === "mov") {
-			$capture_abs_path = $this->capture(Thumb::$FFMPEG_CMD, $source_abs_path);
-			if ($capture_abs_path === null) {
-				$capture_abs_path = $this->capture(Thumb::$AVCONV_CMD, $source_abs_path);
+			$capture_path = $this->capture(Thumb::$FFMPEG_CMD, $source_path);
+			if ($capture_path === null) {
+				$capture_path = $this->capture(Thumb::$AVCONV_CMD, $source_path);
 			}
 		} else if ($type === "doc") {
-			$capture_abs_path = $this->capture(Thumb::$CONVERT_CMD, $source_abs_path);
+			$capture_path = $this->capture(Thumb::$CONVERT_CMD, $source_path);
 		}
 
-		return $this->thumb_href($capture_abs_path, $mode, $width, $height);
+		return $this->thumb_href($capture_path, $mode, $width, $height);
 	}
 
 
-	private function thumb_href($source_abs_path, $mode, $width, $height) {
+	private function thumb_href($source_path, $mode, $width, $height) {
 
-		if (!file_exists($source_abs_path)) {
+		if (!file_exists($source_path)) {
 			return null;
 		}
 
@@ -55,50 +55,50 @@ class Thumb {
 			@mkdir($this->thumbs_path, 0755, true);
 		}
 
-		$name = "thumb-" . sha1("$source_abs_path-$width-$height-$mode") . ".jpg";
-		$thumb_abs_path = $this->thumbs_path . "/" . $name;
-		$thumb_abs_href = $this->thumbs_href . "/" . $name;
+		$name = "thumb-" . sha1("$source_path-$width-$height-$mode") . ".jpg";
+		$thumb_path = $this->thumbs_path . "/" . $name;
+		$thumb_url = $this->thumbs_href . "/" . $name;
 
-		if (!file_exists($thumb_abs_path) || filemtime($source_abs_path) >= filemtime($thumb_abs_path)) {
+		if (!file_exists($thumb_path) || filemtime($source_path) >= filemtime($thumb_path)) {
 
 			$image = new Image();
 
 			$et = false;
 			$opts = $this->app->get_options();
 			if ($opts["thumbnails"]["exif"] === true && function_exists("exif_thumbnail")) {
-				$et = @exif_thumbnail($source_abs_path);
+				$et = @exif_thumbnail($source_path);
 			}
 			if($et !== false) {
-				file_put_contents($thumb_abs_path, $et);
-				$image->set_source($thumb_abs_path);
-				$image->normalize_exif_orientation($source_abs_path);
+				file_put_contents($thumb_path, $et);
+				$image->set_source($thumb_path);
+				$image->normalize_exif_orientation($source_path);
 			} else {
-				$image->set_source($source_abs_path);
+				$image->set_source($source_path);
 			}
 
 			$image->thumb($mode, $width, $height);
-			$image->save_dest_jpeg($thumb_abs_path, 80);
+			$image->save_dest_jpeg($thumb_path, 80);
 		}
 
-		return file_exists($thumb_abs_path) ? $thumb_abs_href : null;
+		return file_exists($thumb_path) ? $thumb_url : null;
 	}
 
 
-	private function capture($cmd, $source_abs_path) {
+	private function capture($cmd, $source_path) {
 
-		if (!file_exists($source_abs_path)) {
+		if (!file_exists($source_path)) {
 			return null;
 		}
 
-		$capture_abs_path = $this->thumbs_path . "/capture-" . sha1($source_abs_path) . ".jpg";
+		$capture_path = $this->thumbs_path . "/capture-" . sha1($source_path) . ".jpg";
 
-		if (!file_exists($capture_abs_path) || filemtime($source_abs_path) >= filemtime($capture_abs_path)) {
-			$cmd = str_replace("[SOURCE]", escapeshellarg($source_abs_path), $cmd);
-			$cmd = str_replace("[TARGET]", escapeshellarg($capture_abs_path), $cmd);
+		if (!file_exists($capture_path) || filemtime($source_path) >= filemtime($capture_path)) {
+			$cmd = str_replace("[SOURCE]", escapeshellarg($source_path), $cmd);
+			$cmd = str_replace("[TARGET]", escapeshellarg($capture_path), $cmd);
 			exec_cmd($cmd);
 		}
 
-		return file_exists($capture_abs_path) ? $capture_abs_path : null;
+		return file_exists($capture_path) ? $capture_path : null;
 	}
 }
 
diff --git a/src/_h5ai/server/php/inc/main.php b/src/_h5ai/server/php/inc/main.php
index 66badf85..bc3a8d02 100644
--- a/src/_h5ai/server/php/inc/main.php
+++ b/src/_h5ai/server/php/inc/main.php
@@ -1,14 +1,25 @@
 <?php
 
-putenv("LANG=en_US.UTF-8");
-date_default_timezone_set("UTC");
-
-normalized_require_once("util.php");
-normalized_require_once("App.php");
-normalized_require_once("Item.php");
 
 
-function create_app() {
+function refl($id, $obj) {
+
+	$s = "<pre class='refl'>";
+	$s .= $id . "  " . var_export($obj, true);
+	$s .= "</pre>\n";
+	echo($s);
+}
+
+
+function init() {
+
+	putenv("LANG=en_US.UTF-8");
+	date_default_timezone_set("UTC");
+
+	define("MIN_PHP_VERSION", "5.3.0");
+	define("IS_PHP_VERSION_SUPPORTED", version_compare(PHP_VERSION, MIN_PHP_VERSION) >= 0);
+
+	define("IS_WIN_OS", strtolower(substr(PHP_OS, 0, 3)) === "win");
 
 	$server_name = null;
 	$server_version = null;
@@ -17,23 +28,67 @@ function create_app() {
 		$server_name = $matches[1];
 		$server_version = $matches[2];
 	}
-
-	$app_abs_path = normalize_path(dirname(dirname(dirname(dirname(__FILE__)))));
+	define("SERVER_NAME", $server_name);
+	define("SERVER_VERSION", $server_version);
 
 	$script_name = getenv("SCRIPT_NAME");
-	if ($server_name === "lighttpd") {
+	if (SERVER_NAME === "lighttpd") {
 		$script_name = preg_replace("#^.*//#", "/", $script_name);
 	}
-	$app_abs_href = dirname(dirname(dirname($script_name)));
+	define("APP_URL", normalize_path(dirname(dirname(dirname($script_name))), true));
+	define("APP_PATH", normalize_path(dirname(dirname(dirname(dirname(__FILE__)))), false));
+
+	define("ROOT_URL", normalize_path(dirname(APP_URL), true));
+	define("ROOT_PATH", normalize_path(dirname(APP_PATH), false));
 
 	$url_parts = parse_url(getenv("REQUEST_URI"));
-	$abs_href = $url_parts["path"];
+	$cur_url = normalize_path($url_parts["path"], true);
+	$rel_url = substr($cur_url, strlen(ROOT_URL));
+	$cur_path = normalize_path(ROOT_PATH . "/" . rawurldecode($rel_url));
+	if (!is_dir($cur_path)) {
+		$cur_url = normalize_path(dirname($cur_url), true);
+		$cur_path = normalize_path(dirname($cur_path), false);
+	}
+	define("CURRENT_URL", $cur_url);
+	define("CURRENT_PATH", $cur_path);
 
-	return new App($server_name, $server_version, $app_abs_path, $app_abs_href, $abs_href);
+	define("MAGIC_SEQUENCE", "={{pkg.name}}=");
+	define("FILE_PREFIX", "_{{pkg.name}}");
+
+	define("INDEX_URL", normalize_path(APP_URL . "server/php/index.php", false));
+	define("CACHE_URL", normalize_path(APP_URL . "cache", true));
+	define("CACHE_PATH", normalize_path(APP_PATH . "/cache", false));
+
+	// refl('DEFINED', array(
+	// 	"PHP_VERSION     " => PHP_VERSION,
+	// 	"PHP_OS          " => PHP_OS,
+	// 	"MIN_PHP_VERSION " => MIN_PHP_VERSION,
+	// 	"IS_PHP_VERSION_SUPPORTED   " => IS_PHP_VERSION_SUPPORTED,
+	// 	"IS_WIN_OS       " => IS_WIN_OS,
+	// 	"SERVER_NAME     " => SERVER_NAME,
+	// 	"SERVER_VERSION  " => SERVER_VERSION,
+	// 	"APP_URL         " => APP_URL,
+	// 	"APP_PATH        " => APP_PATH,
+	// 	"ROOT_URL        " => ROOT_URL,
+	// 	"ROOT_PATH       " => ROOT_PATH,
+	// 	"CURRENT_URL     " => CURRENT_URL,
+	// 	"CURRENT_PATH    " => CURRENT_PATH,
+	// 	"MAGIC_SEQUENCE  " => MAGIC_SEQUENCE,
+	// 	"FILE_PREFIX     " => FILE_PREFIX,
+	// 	"INDEX_URL       " => INDEX_URL,
+	// 	"CACHE_URL       " => CACHE_URL,
+	// 	"CACHE_PATH      " => CACHE_PATH
+	// ));
+	// exit();
 }
 
+init();
 
-$app = create_app();
+normalized_require_once("util.php");
+normalized_require_once("App.php");
+normalized_require_once("Item.php");
+
+$app = new App();
 
 
 if (has_request_param("action")) {
@@ -47,10 +102,7 @@ if (has_request_param("action")) {
 } else {
 
 	header("Content-type: text/html;charset=utf-8");
-
-	global $HREF, $FALLBACK;
-	$HREF = $app->get_app_abs_href();
-	$FALLBACK = $app->get_fallback();
+	define("FALLBACK", $app->get_fallback());
 	normalized_require_once("page.php");
 }
 
diff --git a/src/_h5ai/server/php/inc/page.php.jade b/src/_h5ai/server/php/inc/page.php.jade
index f49aec7e..c03e4f82 100644
--- a/src/_h5ai/server/php/inc/page.php.jade
+++ b/src/_h5ai/server/php/inc/page.php.jade
@@ -1,6 +1,6 @@
 
-- var href = "<?php global $HREF; echo $HREF; ?>"
-- var fallback = "<?php global $FALLBACK; echo $FALLBACK; ?>"
+- var url = "<?= APP_URL ?>"
+- var fallback = "<?= FALLBACK ?>"
 
 doctype 5
 //if lt IE 9
@@ -15,15 +15,15 @@ html.no-js.browser( lang="en" )
 		title index · styled with {{pkg.name}} {{pkg.version}} ({{pkg.url}})
 		meta( name="description", content="index styled with {{pkg.name}} {{pkg.version}} ({{pkg.url}})" )
 		meta( name="viewport", content="width=device-width" )
-		link( rel="shortcut icon", href!="#{href}client/images/app-16x16.ico" )
-		link( rel="apple-touch-icon-precomposed", type="image/png", href!="#{href}client/images/app-48x48.png" )
-		link( rel="apple-touch-icon-precomposed", sizes="57x57", type="image/png", href!="#{href}client/images/app-57x57.png" )
-		link( rel="apple-touch-icon-precomposed", sizes="72x72", type="image/png", href!="#{href}client/images/app-72x72.png" )
-		link( rel="apple-touch-icon-precomposed", sizes="114x114", type="image/png", href!="#{href}client/images/app-114x114.png" )
-		link( rel="apple-touch-icon-precomposed", sizes="144x144", type="image/png", href!="#{href}client/images/app-144x144.png" )
+		link( rel="shortcut icon", href!="#{url}client/images/app-16x16.ico" )
+		link( rel="apple-touch-icon-precomposed", type="image/png", href!="#{url}client/images/app-48x48.png" )
+		link( rel="apple-touch-icon-precomposed", sizes="57x57", type="image/png", href!="#{url}client/images/app-57x57.png" )
+		link( rel="apple-touch-icon-precomposed", sizes="72x72", type="image/png", href!="#{url}client/images/app-72x72.png" )
+		link( rel="apple-touch-icon-precomposed", sizes="114x114", type="image/png", href!="#{url}client/images/app-114x114.png" )
+		link( rel="apple-touch-icon-precomposed", sizes="144x144", type="image/png", href!="#{url}client/images/app-144x144.png" )
 		link( rel="stylesheet", href="//fonts.googleapis.com/css?family=Ubuntu+Mono:400,700,400italic,700italic|Ubuntu:300italic,700italic,300,700" )
-		link( rel="stylesheet", href!="#{href}client/css/styles.css" )
-		script( src!="#{href}client/js/scripts.js" )
+		link( rel="stylesheet", href!="#{url}client/css/styles.css" )
+		script( src!="#{url}client/js/scripts.js" )
 
 	body
 
diff --git a/src/_h5ai/server/php/inc/util.php b/src/_h5ai/server/php/inc/util.php
index 534fcdba..a47cc5ca 100644
--- a/src/_h5ai/server/php/inc/util.php
+++ b/src/_h5ai/server/php/inc/util.php
@@ -1,11 +1,5 @@
 <?php
 
-function normalize_path($path, $trailing_slash = false) {
-
-	$path = str_replace("\\", "/", $path);
-	return preg_match("#^(\w:)?/$#", $path) ? $path : (rtrim($path, "/") . ($trailing_slash ? "/" : ""));
-}
-
 function json_exit($obj = array()) {
 
 	$obj["code"] = 0;
@@ -26,37 +20,17 @@ function has_request_param($key) {
 	return array_key_exists($key, $_REQUEST);
 }
 
-function use_request_params($keys) {
+define("NO_DEFAULT", "__NO_DEFAULT_VALUE__");
+function use_request_param($key, $default = NO_DEFAULT) {
 
-	if (!is_array($keys)) {
-		$keys = func_get_args();
+	if (!array_key_exists($key, $_REQUEST)) {
+		json_fail(101, "parameter '$key' is missing", $default === NO_DEFAULT);
+		return $default;
 	}
 
-	$values = array();
-	foreach ($keys as $key) {
-		json_fail(101, "parameter '$key' is missing", !array_key_exists($key, $_REQUEST));
-		$values[] = $_REQUEST[$key];
-		unset($_REQUEST[$key]);
-	}
-	return $values;
-}
-
-function use_optional_request_params($keys) {
-
-	if (!is_array($keys)) {
-		$keys = func_get_args();
-	}
-
-	$values = array();
-	foreach ($keys as $key) {
-		if (array_key_exists($key, $_REQUEST)) {
-			$values[] = $_REQUEST[$key];
-			unset($_REQUEST[$key]);
-		} else {
-			$values[] = null;
-		}
-	}
-	return $values;
+	$value = $_REQUEST[$key];
+	unset($_REQUEST[$key]);
+	return $value;
 }
 
 function starts_with($sequence, $head) {
diff --git a/src/_h5ai/server/php/index.php b/src/_h5ai/server/php/index.php
index cfb15c19..3bc97245 100644
--- a/src/_h5ai/server/php/index.php
+++ b/src/_h5ai/server/php/index.php
@@ -1,10 +1,14 @@
 <?php
 
+function normalize_path($path, $trailing_slash = false) {
+
+	$path = preg_replace("#\\+|/+#", "/", $path);
+	return preg_match("#^(\w:)?/$#", $path) ? $path : (rtrim($path, "/") . ($trailing_slash ? "/" : ""));
+}
+
 function normalized_require_once($lib) {
 
-	$path = dirname(__FILE__) . "/inc/" . $lib;
-	$path = preg_replace("#\\+|/+#", "/", $path);
-	require_once($path);
+	require_once(normalize_path(dirname(__FILE__) . "/inc/" . $lib, false));
 }
 
 normalized_require_once("main.php");