Env.php

<?php
namespace core;

/**
 * Safe to read environment-variables.
 */
class Env
{
	private static $server = null;

	public static function init()
	{
		if (! isset($_SERVER)) {
			user_error("DevErr: Env-class loaded without SERVER-var");
		}
		self::$server = $_SERVER;
	}

	// Visitor IP
	public static function ip()
	{
		return self::$server["HTTP_X_REAL_IP"] ?? self::$server["REMOTE_ADDR"];
	}
	// HTTP-protocol spoken to client.
	public static function protocol()
	{
		return self::$server["SERVER_PROTOCOL"];
	}
	public static function encoding()
	{
		$enc = "plain";
		$map = [
			"application/json" => "json",
			"text/html" => "html"
		];
		$accept = self::$server["HTTP_ACCEPT"] ?? "";

		foreach ($map as $k => $m) {
			if (strpos($accept, $k) !== false) {
				$enc = $m;
			}
		}

		return $enc;
	}
	// Get browser language and match it on $accept
	// If no match is found $accept[0] is chosen.
	public static function getBrowserLang(array $accept = ["en"])
	{
		if (! isset(self::$server['HTTP_ACCEPT_LANGUAGE'])) {
			return $accept[0];
		}

		$raw = self::$server['HTTP_ACCEPT_LANGUAGE'];
		$langs = substr($raw, 0, strpos($raw, ";"));
		foreach (explode(",", $langs) as $lang) {
			$lang = strtolower($lang);
			if (strpos($lang, "-") !== false) {
				$lang = substr($lang, 0, strpos($lang, "-"));
			}
			if (in_array($lang, $accept)) {
				return $lang;
			}
		}
		return $accept[0];
	}

	// Get previous page
	public static function prev()
	{
		// https://domain.nl/...
		$url = self::$server['HTTP_REFERER'];
		return substr($url, strpos($url, "/", 8));
	}

	// Get previous useragent
	public static function userAgent()
	{
		return self::$server['HTTP_USER_AGENT'] ?? '';
	}

	// Simple base64 auth
	// $users = ["user" => "pass", "user2" => "pass2"...]
	public static function blocking_auth($realm, array $users = [])
	{
		if (count($users) === 0) {
			user_error("DevErr: Env::blocking_auth called without users.");
		}
		$v = self::protocol();

		$requser = self::$server["PHP_AUTH_USER"] ?? "";
		$reqpass = self::$server["PHP_AUTH_PW"] ?? "";
		if ($requser === "" || $reqpass === "") {
			header(sprintf('WWW-Authenticate: Basic realm="%s"', $realm));
			header("HTTP/$v 401 Unauthorized");
			echo "You must enter a valid login ID and password to access this resource\n";
			exit;
		}

		$match = false;
		foreach ($users as $user => $pass) {
			if ($requser === $user && $reqpass === $pass) {
				return;
			}
		}

		header(sprintf('WWW-Authenticate: Basic realm="%s"', $realm));
		header("HTTP/$v 403 Unauthorized");
		echo "You must enter a valid login ID and password to access this resource\n";
		exit;
	}

	// Read HFast-path
	public static function hfastPath()
        {
                $sane = preg_replace("/[^A-Za-z0-9_\/]/", "", self::$server["DOCUMENT_URI"]);
                return str_replace('/action/', '', $sane);
        }
	
	public static function method()
	{
		return self::$server["REQUEST_METHOD"];
	}
	
	public static function url_full()
	{
		return "https://" . self::$server['HTTP_HOST'] . self::$server['REQUEST_URI'] ?? '' . "?" . self::$server['QUERY_STRING'] ?? "";
	}

	public static function ajax()
	{
		return isset(self::$server["HTTP_X_REQUESTED_WITH"]) && self::$server["HTTP_X_REQUESTED_WITH"] === "XMLHttpRequest";
	}

	public static function referer_check() {
		$domain = str_replace("https://", "", str_replace("http://", "", self::$server["HTTP_REFERER"]??""));
		$domain = substr($domain, 0, strpos($domain, "/"));
		return $domain === (self::$server["SERVER_NAME"] ?? "");
	}
	public static function referer() {
                return self::$server["HTTP_REFERER"] ?? null;
        }

        public static function userPass() {
                $requser = Env::$server["PHP_AUTH_USER"] ?? "";
                $reqpass = self::$server["PHP_AUTH_PW"] ?? "";
                return [$requser, $reqpass];
        }

	public static function host() {
		return self::$server['HTTP_HOST'];
	}

        /** environment variable */
        public static function var($key)
        {
                return getenv($key);
        }
}