friendica/boot.php

<?php
/** @file boot.php
 *
 * This file defines some global constants and includes the central App class.
 */

/**
 * Friendica
 *
 * Friendica is a communications platform for integrated social communications
 * utilising decentralised communications and linkage to several indie social
 * projects - as well as popular mainstream providers.
 *
 * Our mission is to free our friends and families from the clutches of
 * data-harvesting corporations, and pave the way to a future where social
 * communications are free and open and flow between alternate providers as
 * easily as email does today.
 */

require_once('include/autoloader.php');

require_once('include/config.php');
require_once('include/network.php');
require_once('include/plugin.php');
require_once('include/text.php');
require_once('include/datetime.php');
require_once('include/pgettext.php');
require_once('include/nav.php');
require_once('include/cache.php');
require_once('library/Mobile_Detect/Mobile_Detect.php');
require_once('include/features.php');
require_once('include/identity.php');
require_once('include/pidfile.php');
require_once('update.php');
require_once('include/dbstructure.php');

define ( 'FRIENDICA_PLATFORM',     'Friendica');
define ( 'FRIENDICA_CODENAME',     'Asparagus');
define ( 'FRIENDICA_VERSION',      '3.5-dev' );
define ( 'DFRN_PROTOCOL_VERSION',  '2.23'    );
define ( 'DB_UPDATE_VERSION',      1200      );

/**
 * @brief Constant with a HTML line break.
 *
 * Contains a HTML line break (br) element and a real carriage return with line
 * feed for the source.
 * This can be used in HTML and JavaScript where needed a line break.
 */
define ( 'EOL',                    "<br />\r\n"     );
define ( 'ATOM_TIME',              'Y-m-d\TH:i:s\Z' );


/**
 * @brief Image storage quality.
 * 
 * Lower numbers save space at cost of image detail.
 * For ease of upgrade, please do not change here. Change jpeg quality with
 * $a->config['system']['jpeg_quality'] = n;
 * in .htconfig.php, where n is netween 1 and 100, and with very poor results
 * below about 50
 *
 */

define ( 'JPEG_QUALITY',            100  );
/**
 * $a->config['system']['png_quality'] from 0 (uncompressed) to 9
 */
define ( 'PNG_QUALITY',             8  );

/**
 *
 * An alternate way of limiting picture upload sizes. Specify the maximum pixel
 * length that pictures are allowed to be (for non-square pictures, it will apply
 * to the longest side). Pictures longer than this length will be resized to be
 * this length (on the longest side, the other side will be scaled appropriately).
 * Modify this value using
 *
 *    $a->config['system']['max_image_length'] = n;
 *
 * in .htconfig.php
 *
 * If you don't want to set a maximum length, set to -1. The default value is
 * defined by 'MAX_IMAGE_LENGTH' below.
 *
 */
define ( 'MAX_IMAGE_LENGTH',        -1  );


/**
 * Not yet used
 */

define ( 'DEFAULT_DB_ENGINE',  'MyISAM'  );

/**
 * @name SSL Policy
 * 
 * SSL redirection policies
 * @{
 */
define ( 'SSL_POLICY_NONE',         0 );
define ( 'SSL_POLICY_FULL',         1 );
define ( 'SSL_POLICY_SELFSIGN',     2 );
/* @}*/

/**
 * @name Logger
 * 
 * log levels
 * @{
 */
define ( 'LOGGER_NORMAL',          0 );
define ( 'LOGGER_TRACE',           1 );
define ( 'LOGGER_DEBUG',           2 );
define ( 'LOGGER_DATA',            3 );
define ( 'LOGGER_ALL',             4 );
/* @}*/

/**
 * @name Cache
 * 
 * Cache levels
 * @{
 */
define ( 'CACHE_MONTH',            0 );
define ( 'CACHE_WEEK',             1 );
define ( 'CACHE_DAY',              2 );
define ( 'CACHE_HOUR',             3 );
/* @}*/

/**
 * @name Register
 * 
 * Registration policies
 * @{
 */
define ( 'REGISTER_CLOSED',        0 );
define ( 'REGISTER_APPROVE',       1 );
define ( 'REGISTER_OPEN',          2 );
/** @}*/

/**
 * @name Contact_is
 * 
 * Relationship types
 * @{
 */
define ( 'CONTACT_IS_FOLLOWER', 1);
define ( 'CONTACT_IS_SHARING',  2);
define ( 'CONTACT_IS_FRIEND',   3);
/** @}*/

/**
 * @name Update
 * 
 * DB update return values
 * @{
 */
define ( 'UPDATE_SUCCESS', 0);
define ( 'UPDATE_FAILED',  1);
/** @}*/


/**
 * @name page/profile types
 *
 * PAGE_NORMAL is a typical personal profile account
 * PAGE_SOAPBOX automatically approves all friend requests as CONTACT_IS_SHARING, (readonly)
 * PAGE_COMMUNITY automatically approves all friend requests as CONTACT_IS_SHARING, but with
 *      write access to wall and comments (no email and not included in page owner's ACL lists)
 * PAGE_FREELOVE automatically approves all friend requests as full friends (CONTACT_IS_FRIEND).
 *
 * @{
 */
define ( 'PAGE_NORMAL',            0 );
define ( 'PAGE_SOAPBOX',           1 );
define ( 'PAGE_COMMUNITY',         2 );
define ( 'PAGE_FREELOVE',          3 );
define ( 'PAGE_BLOG',              4 );
define ( 'PAGE_PRVGROUP',          5 );
/** @}*/

/**
 * @name CP
 * 
 * Type of the community page
 * @{
 */
define ( 'CP_NO_COMMUNITY_PAGE',   -1 );
define ( 'CP_USERS_ON_SERVER',     0 );
define ( 'CP_GLOBAL_COMMUNITY',    1 );
/** @}*/

/**
 * @name Network
 * 
 * Network and protocol family types
 * @{
 */
define ( 'NETWORK_DFRN',             'dfrn');    // Friendica, Mistpark, other DFRN implementations
define ( 'NETWORK_ZOT',              'zot!');    // Zot!
define ( 'NETWORK_OSTATUS',          'stat');    // status.net, identi.ca, GNU-social, other OStatus implementations
define ( 'NETWORK_FEED',             'feed');    // RSS/Atom feeds with no known "post/notify" protocol
define ( 'NETWORK_DIASPORA',         'dspr');    // Diaspora
define ( 'NETWORK_MAIL',             'mail');    // IMAP/POP
define ( 'NETWORK_MAIL2',            'mai2');    // extended IMAP/POP
define ( 'NETWORK_FACEBOOK',         'face');    // Facebook API
define ( 'NETWORK_LINKEDIN',         'lnkd');    // LinkedIn
define ( 'NETWORK_XMPP',             'xmpp');    // XMPP
define ( 'NETWORK_MYSPACE',          'mysp');    // MySpace
define ( 'NETWORK_GPLUS',            'goog');    // Google+
define ( 'NETWORK_PUMPIO',           'pump');    // pump.io
define ( 'NETWORK_TWITTER',          'twit');    // Twitter
define ( 'NETWORK_DIASPORA2',        'dspc');    // Diaspora connector
define ( 'NETWORK_STATUSNET',        'stac');    // Statusnet connector
define ( 'NETWORK_APPNET',           'apdn');    // app.net
define ( 'NETWORK_NEWS',             'nntp');    // Network News Transfer Protocol
define ( 'NETWORK_ICALENDAR',        'ical');    // iCalendar
define ( 'NETWORK_PHANTOM',          'unkn');    // Place holder
/** @}*/

/**
 * These numbers are used in stored permissions
 * and existing allocations MUST NEVER BE CHANGED
 * OR RE-ASSIGNED! You may only add to them.
 */

$netgroup_ids = array(
	NETWORK_DFRN     => (-1),
	NETWORK_ZOT      => (-2),
	NETWORK_OSTATUS  => (-3),
	NETWORK_FEED     => (-4),
	NETWORK_DIASPORA => (-5),
	NETWORK_MAIL     => (-6),
	NETWORK_MAIL2    => (-7),
	NETWORK_FACEBOOK => (-8),
	NETWORK_LINKEDIN => (-9),
	NETWORK_XMPP     => (-10),
	NETWORK_MYSPACE  => (-11),
	NETWORK_GPLUS    => (-12),
	NETWORK_PUMPIO   => (-13),
	NETWORK_TWITTER  => (-14),
	NETWORK_DIASPORA2 => (-15),
	NETWORK_STATUSNET => (-16),
	NETWORK_APPNET    => (-17),
	NETWORK_NEWS      => (-18),
	NETWORK_ICALENDAR => (-19),

	NETWORK_PHANTOM  => (-127),
);


/**
 * Maximum number of "people who like (or don't like) this"  that we will list by name
 */

define ( 'MAX_LIKERS',    75);

/**
 * Communication timeout
 */

define ( 'ZCURL_TIMEOUT' , (-1));


/**
 * @name Notify
 * 
 * Email notification options
 * @{
 */
define ( 'NOTIFY_INTRO',    0x0001 );
define ( 'NOTIFY_CONFIRM',  0x0002 );
define ( 'NOTIFY_WALL',     0x0004 );
define ( 'NOTIFY_COMMENT',  0x0008 );
define ( 'NOTIFY_MAIL',     0x0010 );
define ( 'NOTIFY_SUGGEST',  0x0020 );
define ( 'NOTIFY_PROFILE',  0x0040 );
define ( 'NOTIFY_TAGSELF',  0x0080 );
define ( 'NOTIFY_TAGSHARE', 0x0100 );
define ( 'NOTIFY_POKE',     0x0200 );
define ( 'NOTIFY_SHARE',    0x0400 );

define ( 'NOTIFY_SYSTEM',   0x8000 );
/* @}*/


/**
 * @name Term
 * 
 * Tag/term types
 * @{
 */
define ( 'TERM_UNKNOWN',   0 );
define ( 'TERM_HASHTAG',   1 );
define ( 'TERM_MENTION',   2 );
define ( 'TERM_CATEGORY',  3 );
define ( 'TERM_PCATEGORY', 4 );
define ( 'TERM_FILE',      5 );
define ( 'TERM_SAVEDSEARCH', 6 );
define ( 'TERM_CONVERSATION', 7 );

define ( 'TERM_OBJ_POST',  1 );
define ( 'TERM_OBJ_PHOTO', 2 );



/**
 * @name Namespaces
 * 
 * Various namespaces we may need to parse
 * @{
 */
define ( 'NAMESPACE_ZOT',             'http://purl.org/zot' );
define ( 'NAMESPACE_DFRN' ,           'http://purl.org/macgirvin/dfrn/1.0' );
define ( 'NAMESPACE_THREAD' ,         'http://purl.org/syndication/thread/1.0' );
define ( 'NAMESPACE_TOMB' ,           'http://purl.org/atompub/tombstones/1.0' );
define ( 'NAMESPACE_ACTIVITY',        'http://activitystrea.ms/spec/1.0/' );
define ( 'NAMESPACE_ACTIVITY_SCHEMA', 'http://activitystrea.ms/schema/1.0/' );
define ( 'NAMESPACE_MEDIA',           'http://purl.org/syndication/atommedia' );
define ( 'NAMESPACE_SALMON_ME',       'http://salmon-protocol.org/ns/magic-env' );
define ( 'NAMESPACE_OSTATUSSUB',      'http://ostatus.org/schema/1.0/subscribe' );
define ( 'NAMESPACE_GEORSS',          'http://www.georss.org/georss' );
define ( 'NAMESPACE_POCO',            'http://portablecontacts.net/spec/1.0' );
define ( 'NAMESPACE_FEED',            'http://schemas.google.com/g/2010#updates-from' );
define ( 'NAMESPACE_OSTATUS',         'http://ostatus.org/schema/1.0' );
define ( 'NAMESPACE_STATUSNET',       'http://status.net/schema/api/1/' );
define ( 'NAMESPACE_ATOM1',           'http://www.w3.org/2005/Atom' );
/* @}*/

/**
 * @name Activity
 * 
 * Activity stream defines
 * @{
 */
define ( 'ACTIVITY_LIKE',        NAMESPACE_ACTIVITY_SCHEMA . 'like' );
define ( 'ACTIVITY_DISLIKE',     NAMESPACE_DFRN            . '/dislike' );
define ( 'ACTIVITY_ATTEND',      NAMESPACE_ZOT             . '/activity/attendyes' );
define ( 'ACTIVITY_ATTENDNO',    NAMESPACE_ZOT             . '/activity/attendno' );
define ( 'ACTIVITY_ATTENDMAYBE', NAMESPACE_ZOT             . '/activity/attendmaybe' );

define ( 'ACTIVITY_OBJ_HEART',   NAMESPACE_DFRN            . '/heart' );

define ( 'ACTIVITY_FRIEND',      NAMESPACE_ACTIVITY_SCHEMA . 'make-friend' );
define ( 'ACTIVITY_REQ_FRIEND',  NAMESPACE_ACTIVITY_SCHEMA . 'request-friend' );
define ( 'ACTIVITY_UNFRIEND',    NAMESPACE_ACTIVITY_SCHEMA . 'remove-friend' );
define ( 'ACTIVITY_FOLLOW',      NAMESPACE_ACTIVITY_SCHEMA . 'follow' );
define ( 'ACTIVITY_UNFOLLOW',    NAMESPACE_ACTIVITY_SCHEMA . 'stop-following' );
define ( 'ACTIVITY_JOIN',        NAMESPACE_ACTIVITY_SCHEMA . 'join' );

define ( 'ACTIVITY_POST',        NAMESPACE_ACTIVITY_SCHEMA . 'post' );
define ( 'ACTIVITY_UPDATE',      NAMESPACE_ACTIVITY_SCHEMA . 'update' );
define ( 'ACTIVITY_TAG',         NAMESPACE_ACTIVITY_SCHEMA . 'tag' );
define ( 'ACTIVITY_FAVORITE',    NAMESPACE_ACTIVITY_SCHEMA . 'favorite' );
define ( 'ACTIVITY_SHARE',       NAMESPACE_ACTIVITY_SCHEMA . 'share' );

define ( 'ACTIVITY_POKE',        NAMESPACE_ZOT . '/activity/poke' );
define ( 'ACTIVITY_MOOD',        NAMESPACE_ZOT . '/activity/mood' );

define ( 'ACTIVITY_OBJ_BOOKMARK', NAMESPACE_ACTIVITY_SCHEMA . 'bookmark' );
define ( 'ACTIVITY_OBJ_COMMENT', NAMESPACE_ACTIVITY_SCHEMA . 'comment' );
define ( 'ACTIVITY_OBJ_NOTE',    NAMESPACE_ACTIVITY_SCHEMA . 'note' );
define ( 'ACTIVITY_OBJ_PERSON',  NAMESPACE_ACTIVITY_SCHEMA . 'person' );
define ( 'ACTIVITY_OBJ_IMAGE',   NAMESPACE_ACTIVITY_SCHEMA . 'image' );
define ( 'ACTIVITY_OBJ_PHOTO',   NAMESPACE_ACTIVITY_SCHEMA . 'photo' );
define ( 'ACTIVITY_OBJ_VIDEO',   NAMESPACE_ACTIVITY_SCHEMA . 'video' );
define ( 'ACTIVITY_OBJ_P_PHOTO', NAMESPACE_ACTIVITY_SCHEMA . 'profile-photo' );
define ( 'ACTIVITY_OBJ_ALBUM',   NAMESPACE_ACTIVITY_SCHEMA . 'photo-album' );
define ( 'ACTIVITY_OBJ_EVENT',   NAMESPACE_ACTIVITY_SCHEMA . 'event' );
define ( 'ACTIVITY_OBJ_GROUP',   NAMESPACE_ACTIVITY_SCHEMA . 'group' );
define ( 'ACTIVITY_OBJ_TAGTERM', NAMESPACE_DFRN            . '/tagterm' );
define ( 'ACTIVITY_OBJ_PROFILE', NAMESPACE_DFRN            . '/profile' );
define ( 'ACTIVITY_OBJ_QUESTION', 'http://activityschema.org/object/question' );
/* @}*/

/**
 * @name Gravity
 * 
 * Item weight for query ordering
 * @{
 */
define ( 'GRAVITY_PARENT',       0);
define ( 'GRAVITY_LIKE',         3);
define ( 'GRAVITY_COMMENT',      6);
/* @}*/

/**
 * @name Priority
 *
 * Process priority for the worker
 * @{
 */
define('PRIORITY_UNDEFINED', 0);
define('PRIORITY_SYSTEM',   10);
define('PRIORITY_HIGH',     20);
define('PRIORITY_MEDIUM',   30);
define('PRIORITY_LOW',      40);
/* @}*/


// Normally this constant is defined - but not if "pcntl" isn't installed
if (!defined("SIGTERM"))
	define("SIGTERM", 15);

/**
 *
 * Reverse the effect of magic_quotes_gpc if it is enabled.
 * Please disable magic_quotes_gpc so we don't have to do this.
 * See http://php.net/manual/en/security.magicquotes.disabling.php
 *
 */

function startup() {

	error_reporting(E_ERROR | E_WARNING | E_PARSE);

	set_time_limit(0);

	// This has to be quite large to deal with embedded private photos
	ini_set('pcre.backtrack_limit', 500000);


	if (get_magic_quotes_gpc()) {
		$process = array(&$_GET, &$_POST, &$_COOKIE, &$_REQUEST);
		while (list($key, $val) = each($process)) {
			foreach ($val as $k => $v) {
				unset($process[$key][$k]);
				if (is_array($v)) {
					$process[$key][stripslashes($k)] = $v;
					$process[] = &$process[$key][stripslashes($k)];
				} else {
					$process[$key][stripslashes($k)] = stripslashes($v);
				}
			}
		}
		unset($process);
	}

}

/**
 *
 * class: App
 * 
 * @brief Our main application structure for the life of this page.
 * 
 * Primarily deals with the URL that got us here
 * and tries to make some sense of it, and
 * stores our page contents and config storage
 * and anything else that might need to be passed around
 * before we spit the page out.
 *
 */
class App {

	public  $module_loaded = false;
	public  $query_string;
	public  $config;
	public  $page;
	public  $profile;
	public  $profile_uid;
	public  $user;
	public  $cid;
	public  $contact;
	public  $contacts;
	public  $page_contact;
	public  $content;
	public  $data = array();
	public  $error = false;
	public  $cmd;
	public  $argv;
	public  $argc;
	public  $module;
	public  $pager;
	public  $strings;
	public  $path;
	public  $hooks;
	public  $timezone;
	public  $interactive = true;
	public  $plugins;
	public  $apps = array();
	public  $identities;
	public	$is_mobile = false;
	public	$is_tablet = false;
	public	$is_friendica_app;
	public	$performance = array();
	public	$callstack = array();
	public	$theme_info = array();
	public  $backend = true;

	public $nav_sel;

	public $category;


	// Allow themes to control internal parameters
	// by changing App values in theme.php

	public	$sourcename = '';
	public	$videowidth = 425;
	public	$videoheight = 350;
	public	$force_max_items = 0;
	public	$theme_thread_allow = true;
	public	$theme_events_in_profile = true;

	/**
	 * @brief An array for all theme-controllable parameters
	 *
	 * Mostly unimplemented yet. Only options 'template_engine' and
	 * beyond are used.
	 */
	public	$theme = array(
		'sourcename' => '',
		'videowidth' => 425,
		'videoheight' => 350,
		'force_max_items' => 0,
		'thread_allow' => true,
		'stylesheet' => '',
		'template_engine' => 'smarty3',
	);

	/**
	 * @brief An array of registered template engines ('name'=>'class name')
	 */
	public $template_engines = array();
	/**
	 * @brief An array of instanced template engines ('name'=>'instance')
	 */
	public $template_engine_instance = array();

	public $process_id;

	private $ldelim = array(
		'internal' => '',
		'smarty3' => '{{'
	);
	private $rdelim = array(
		'internal' => '',
		'smarty3' => '}}'
	);

	private $scheme;
	private $hostname;
	private $baseurl;
	private $db;

	private $curl_code;
	private $curl_content_type;
	private $curl_headers;

	private $cached_profile_image;
	private $cached_profile_picdate;

	private static $a;

	/**
	 * @brief App constructor.
	 */
	function __construct() {

		global $default_timezone;

		$hostname = "";

		if (file_exists(".htpreconfig.php"))
			@include(".htpreconfig.php");

		$this->timezone = ((x($default_timezone)) ? $default_timezone : 'UTC');

		date_default_timezone_set($this->timezone);

		$this->performance["start"] = microtime(true);
		$this->performance["database"] = 0;
		$this->performance["database_write"] = 0;
		$this->performance["network"] = 0;
		$this->performance["file"] = 0;
		$this->performance["rendering"] = 0;
		$this->performance["parser"] = 0;
		$this->performance["marktime"] = 0;
		$this->performance["markstart"] = microtime(true);

		$this->callstack["database"] = array();
		$this->callstack["network"] = array();
		$this->callstack["file"] = array();
		$this->callstack["rendering"] = array();
		$this->callstack["parser"] = array();

		$this->config = array();
		$this->page = array();
		$this->pager= array();

		$this->query_string = '';

		$this->process_id = uniqid("log", true);

		startup();

		set_include_path(
				'include' . PATH_SEPARATOR
				. 'library' . PATH_SEPARATOR
				. 'library/phpsec' . PATH_SEPARATOR
				. 'library/langdet' . PATH_SEPARATOR
				. '.' );


		$this->scheme = 'http';
		if((x($_SERVER,'HTTPS') && $_SERVER['HTTPS']) ||
		   (x($_SERVER['HTTP_FORWARDED']) && preg_match("/proto=https/", $_SERVER['HTTP_FORWARDED'])) ||
		   (x($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https') ||
		   (x($_SERVER['HTTP_X_FORWARDED_SSL']) && $_SERVER['HTTP_X_FORWARDED_SSL'] == 'on') ||
		   (x($_SERVER['FRONT_END_HTTPS']) && $_SERVER['FRONT_END_HTTPS'] == 'on') ||
		   (x($_SERVER,'SERVER_PORT') && (intval($_SERVER['SERVER_PORT']) == 443)) // XXX: reasonable assumption, but isn't this hardcoding too much?
		   ) {
			$this->scheme = 'https';
		   }

		if(x($_SERVER,'SERVER_NAME')) {
			$this->hostname = $_SERVER['SERVER_NAME'];

			if(x($_SERVER,'SERVER_PORT') && $_SERVER['SERVER_PORT'] != 80 && $_SERVER['SERVER_PORT'] != 443)
				$this->hostname .= ':' . $_SERVER['SERVER_PORT'];
			/*
			 * Figure out if we are running at the top of a domain
			 * or in a sub-directory and adjust accordingly
			 */

			$path = trim(dirname($_SERVER['SCRIPT_NAME']),'/\\');
			if(isset($path) && strlen($path) && ($path != $this->path))
				$this->path = $path;
		}

		if ($hostname != "")
			$this->hostname = $hostname;

		if (is_array($_SERVER["argv"]) && $_SERVER["argc"]>1 && substr(end($_SERVER["argv"]), 0, 4)=="http" ) {
			$this->set_baseurl(array_pop($_SERVER["argv"]) );
			$_SERVER["argc"] --;
		}

		#set_include_path("include/$this->hostname" . PATH_SEPARATOR . get_include_path());

		if((x($_SERVER,'QUERY_STRING')) && substr($_SERVER['QUERY_STRING'],0,9) === "pagename=") {
			$this->query_string = substr($_SERVER['QUERY_STRING'],9);
			// removing trailing / - maybe a nginx problem
			if (substr($this->query_string, 0, 1) == "/")
				$this->query_string = substr($this->query_string, 1);
		} elseif((x($_SERVER,'QUERY_STRING')) && substr($_SERVER['QUERY_STRING'],0,2) === "q=") {
			$this->query_string = substr($_SERVER['QUERY_STRING'],2);
			// removing trailing / - maybe a nginx problem
			if (substr($this->query_string, 0, 1) == "/")
				$this->query_string = substr($this->query_string, 1);
		}

		if (x($_GET,'pagename'))
			$this->cmd = trim($_GET['pagename'],'/\\');
		elseif (x($_GET,'q'))
			$this->cmd = trim($_GET['q'],'/\\');


		// fix query_string
		$this->query_string = str_replace($this->cmd."&",$this->cmd."?", $this->query_string);


		// unix style "homedir"

		if(substr($this->cmd,0,1) === '~')
			$this->cmd = 'profile/' . substr($this->cmd,1);

		// Diaspora style profile url

		if(substr($this->cmd,0,2) === 'u/')
			$this->cmd = 'profile/' . substr($this->cmd,2);


		/*
		 *
		 * Break the URL path into C style argc/argv style arguments for our
		 * modules. Given "http://example.com/module/arg1/arg2", $this->argc
		 * will be 3 (integer) and $this->argv will contain:
		 *   [0] => 'module'
		 *   [1] => 'arg1'
		 *   [2] => 'arg2'
		 *
		 *
		 * There will always be one argument. If provided a naked domain
		 * URL, $this->argv[0] is set to "home".
		 *
		 */

		$this->argv = explode('/',$this->cmd);
		$this->argc = count($this->argv);
		if((array_key_exists('0',$this->argv)) && strlen($this->argv[0])) {
			$this->module = str_replace(".", "_", $this->argv[0]);
			$this->module = str_replace("-", "_", $this->module);
		}
		else {
			$this->argc = 1;
			$this->argv = array('home');
			$this->module = 'home';
		}

		/*
		 * See if there is any page number information, and initialise
		 * pagination
		 */

		$this->pager['page'] = ((x($_GET,'page') && intval($_GET['page']) > 0) ? intval($_GET['page']) : 1);
		$this->pager['itemspage'] = 50;
		$this->pager['start'] = ($this->pager['page'] * $this->pager['itemspage']) - $this->pager['itemspage'];
		if($this->pager['start'] < 0)
			$this->pager['start'] = 0;
		$this->pager['total'] = 0;

		/*
		 * Detect mobile devices
		 */

		$mobile_detect = new Mobile_Detect();
		$this->is_mobile = $mobile_detect->isMobile();
		$this->is_tablet = $mobile_detect->isTablet();

		// Friendica-Client
		$this->is_friendica_app = ($_SERVER['HTTP_USER_AGENT'] == "Apache-HttpClient/UNAVAILABLE (java 1.4)");

		/*
		 * register template engines
		 */
		$dc = get_declared_classes();
		foreach ($dc as $k) {
			if (in_array("ITemplateEngine", class_implements($k))){
				$this->register_template_engine($k);
			}
		}

		self::$a = $this;

	}

	function get_basepath() {

		$basepath = get_config("system", "basepath");

		if ($basepath == "")
			$basepath = dirname(__FILE__);

		if ($basepath == "")
			$basepath = $_SERVER["DOCUMENT_ROOT"];

		if ($basepath == "")
			$basepath = $_SERVER["PWD"];

		return($basepath);
	}

	function get_scheme() {
		return($this->scheme);
	}

	function get_baseurl($ssl = false) {

		// Is the function called statically?
		if (!is_object($this))
			return(self::$a->get_baseurl($ssl));

		$scheme = $this->scheme;

		if((x($this->config,'system')) && (x($this->config['system'],'ssl_policy'))) {
			if(intval($this->config['system']['ssl_policy']) === intval(SSL_POLICY_FULL))
				$scheme = 'https';

			//	Basically, we have $ssl = true on any links which can only be seen by a logged in user
			//	(and also the login link). Anything seen by an outsider will have it turned off.

			if($this->config['system']['ssl_policy'] == SSL_POLICY_SELFSIGN) {
				if($ssl)
					$scheme = 'https';
				else
					$scheme = 'http';
			}
		}

		if (get_config('config','hostname') != "")
			$this->hostname = get_config('config','hostname');

		$this->baseurl = $scheme . "://" . $this->hostname . ((isset($this->path) && strlen($this->path)) ? '/' . $this->path : '' );
		return $this->baseurl;
	}

	function set_baseurl($url) {
		$parsed = @parse_url($url);

		$this->baseurl = $url;

		if($parsed) {
			$this->scheme = $parsed['scheme'];

			$hostname = $parsed['host'];
			if(x($parsed,'port'))
				$hostname .= ':' . $parsed['port'];
			if(x($parsed,'path'))
				$this->path = trim($parsed['path'],'\\/');

			if (file_exists(".htpreconfig.php"))
				@include(".htpreconfig.php");

			if (get_config('config','hostname') != "")
				$this->hostname = get_config('config','hostname');

			if (!isset($this->hostname) OR ($this->hostname == ""))
				$this->hostname = $hostname;
		}

	}

	function get_hostname() {
		if (get_config('config','hostname') != "")
			$this->hostname = get_config('config','hostname');

		return $this->hostname;
	}

	function set_hostname($h) {
		$this->hostname = $h;
	}

	function set_path($p) {
		$this->path = trim(trim($p),'/');
	}

	function get_path() {
		return $this->path;
	}

	function set_pager_total($n) {
		$this->pager['total'] = intval($n);
	}

	function set_pager_itemspage($n) {
		$this->pager['itemspage'] = ((intval($n) > 0) ? intval($n) : 0);
		$this->pager['start'] = ($this->pager['page'] * $this->pager['itemspage']) - $this->pager['itemspage'];
	}

	function set_pager_page($n) {
		$this->pager['page'] = $n;
		$this->pager['start'] = ($this->pager['page'] * $this->pager['itemspage']) - $this->pager['itemspage'];
	}

	function init_pagehead() {
		$interval = ((local_user()) ? get_pconfig(local_user(),'system','update_interval') : 40000);

		// If the update is "deactivated" set it to the highest integer number (~24 days)
		if ($interval < 0)
			$interval = 2147483647;

		if($interval < 10000)
			$interval = 40000;

		// compose the page title from the sitename and the
		// current module called
		if (!$this->module=='')
		{
		    $this->page['title'] = $this->config['sitename'].' ('.$this->module.')';
		} else {
		    $this->page['title'] = $this->config['sitename'];
		}

		/* put the head template at the beginning of page['htmlhead']
		 * since the code added by the modules frequently depends on it
		 * being first
		 */
		if(!isset($this->page['htmlhead']))
			$this->page['htmlhead'] = '';

		// If we're using Smarty, then doing replace_macros() will replace
		// any unrecognized variables with a blank string. Since we delay
		// replacing $stylesheet until later, we need to replace it now
		// with another variable name
		if($this->theme['template_engine'] === 'smarty3')
			$stylesheet = $this->get_template_ldelim('smarty3') . '$stylesheet' . $this->get_template_rdelim('smarty3');
		else
			$stylesheet = '$stylesheet';

		$shortcut_icon = get_config("system", "shortcut_icon");
		if ($shortcut_icon == "")
			$shortcut_icon = "images/friendica-32.png";

		$touch_icon = get_config("system", "touch_icon");
		if ($touch_icon == "")
			$touch_icon = "images/friendica-128.png";

		// get data wich is needed for infinite scroll on the network page
		$invinite_scroll = infinite_scroll_data($this->module);

		$tpl = get_markup_template('head.tpl');
		$this->page['htmlhead'] = replace_macros($tpl,array(
			'$baseurl' => $this->get_baseurl(), // FIXME for z_path!!!!
			'$local_user' => local_user(),
			'$generator' => 'Friendica' . ' ' . FRIENDICA_VERSION,
			'$delitem' => t('Delete this item?'),
			'$comment' => t('Comment'),
			'$showmore' => t('show more'),
			'$showfewer' => t('show fewer'),
			'$update_interval' => $interval,
			'$shortcut_icon' => $shortcut_icon,
			'$touch_icon' => $touch_icon,
			'$stylesheet' => $stylesheet,
			'$infinite_scroll' => $invinite_scroll,
		)) . $this->page['htmlhead'];
	}

	function init_page_end() {
		if(!isset($this->page['end']))
			$this->page['end'] = '';
		$tpl = get_markup_template('end.tpl');
		$this->page['end'] = replace_macros($tpl,array(
			'$baseurl' => $this->get_baseurl() // FIXME for z_path!!!!
		)) . $this->page['end'];
	}

	function set_curl_code($code) {
		$this->curl_code = $code;
	}

	function get_curl_code() {
		return $this->curl_code;
	}

	function set_curl_content_type($content_type) {
		$this->curl_content_type = $content_type;
	}

	function get_curl_content_type() {
		return $this->curl_content_type;
	}

	function set_curl_headers($headers) {
		$this->curl_headers = $headers;
	}

	function get_curl_headers() {
		return $this->curl_headers;
	}

	function get_cached_avatar_image($avatar_image){
		return $avatar_image;

		// The following code is deactivated. It doesn't seem to make any sense and it slows down the system.
		/*
		if($this->cached_profile_image[$avatar_image])
			return $this->cached_profile_image[$avatar_image];

		$path_parts = explode("/",$avatar_image);
		$common_filename = $path_parts[count($path_parts)-1];

		if($this->cached_profile_picdate[$common_filename]){
			$this->cached_profile_image[$avatar_image] = $avatar_image . $this->cached_profile_picdate[$common_filename];
		} else {
			$r = q("SELECT `contact`.`avatar-date` AS picdate FROM `contact` WHERE `contact`.`thumb` like '%%/%s'",
				$common_filename);
			if(! dbm::is_result($r)){
				$this->cached_profile_image[$avatar_image] = $avatar_image;
			} else {
				$this->cached_profile_picdate[$common_filename] = "?rev=".urlencode($r[0]['picdate']);
				$this->cached_profile_image[$avatar_image] = $avatar_image.$this->cached_profile_picdate[$common_filename];
			}
		}
		return $this->cached_profile_image[$avatar_image];
		*/
	}


	/**
	 * @brief Removes the baseurl from an url. This avoids some mixed content problems.
	 *
	 * @param string $url
	 *
	 * @return string The cleaned url
	 */
	function remove_baseurl($url){

		// Is the function called statically?
		if (!is_object($this))
			return(self::$a->remove_baseurl($url));

		$url = normalise_link($url);
		$base = normalise_link($this->get_baseurl());
		$url = str_replace($base."/", "", $url);
		return $url;
	}

	/**
	 * @brief Register template engine class
	 * 
	 * If $name is "", is used class static property $class::$name
	 * 
	 * @param string $class
	 * @param string $name
	 */
	function register_template_engine($class, $name = '') {
		if ($name===""){
			$v = get_class_vars( $class );
			if(x($v,"name")) $name = $v['name'];
		}
		if ($name===""){
			echo "template engine <tt>$class</tt> cannot be registered without a name.\n";
			killme();
		}
		$this->template_engines[$name] = $class;
	}

	/**
	 * @brief Return template engine instance.
	 * 
	 * If $name is not defined, return engine defined by theme,
	 * or default
	 *
	 * @param strin $name Template engine name
	 * @return object Template Engine instance
	 */
	function template_engine($name = ''){
		if ($name!=="") {
			$template_engine = $name;
		} else {
			$template_engine = 'smarty3';
			if (x($this->theme, 'template_engine')) {
				$template_engine = $this->theme['template_engine'];
			}
		}

		if (isset($this->template_engines[$template_engine])){
			if(isset($this->template_engine_instance[$template_engine])){
				return $this->template_engine_instance[$template_engine];
			} else {
				$class = $this->template_engines[$template_engine];
				$obj = new $class;
				$this->template_engine_instance[$template_engine] = $obj;
				return $obj;
			}
		}

		echo "template engine <tt>$template_engine</tt> is not registered!\n"; killme();
	}

	/**
	 * @brief Returns the active template engine.
	 *
	 * @return string
	 */
	function get_template_engine() {
		return $this->theme['template_engine'];
	}

	function set_template_engine($engine = 'smarty3') {
		$this->theme['template_engine'] = $engine;
		/*
		$this->theme['template_engine'] = 'smarty3';

		switch($engine) {
			case 'smarty3':
				if(is_writable('view/smarty3/'))
					$this->theme['template_engine'] = 'smarty3';
				break;
			default:
				break;
		}
		*/
	}

	function get_template_ldelim($engine = 'smarty3') {
		return $this->ldelim[$engine];
	}

	function get_template_rdelim($engine = 'smarty3') {
		return $this->rdelim[$engine];
	}

	function save_timestamp($stamp, $value) {
		$duration = (float)(microtime(true)-$stamp);

		if (!isset($this->performance[$value])) {
			// Prevent ugly E_NOTICE
			$this->performance[$value] = 0;
		}

		$this->performance[$value] += (float)$duration;
		$this->performance["marktime"] += (float)$duration;

		$callstack = $this->callstack();

		if (!isset($this->callstack[$value][$callstack])) {
			// Prevent ugly E_NOTICE
			$this->callstack[$value][$callstack] = 0;
		}

		$this->callstack[$value][$callstack] += (float)$duration;

	}

	/**
	 * @brief Returns a string with a callstack. Can be used for logging.
	 *
	 * @return string
	 */
	function callstack() {
		$trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 6);

		// We remove the first two items from the list since they contain data that we don't need.
		array_shift($trace);
		array_shift($trace);

		$callstack = array();
		foreach ($trace AS $func)
			$callstack[] = $func["function"];

		return implode(", ", $callstack);
	}

	function mark_timestamp($mark) {
		//$this->performance["markstart"] -= microtime(true) - $this->performance["marktime"];
		$this->performance["markstart"] = microtime(true) - $this->performance["markstart"] - $this->performance["marktime"];
	}

	function get_useragent() {
		return(FRIENDICA_PLATFORM." '".FRIENDICA_CODENAME."' ".FRIENDICA_VERSION."-".DB_UPDATE_VERSION."; ".$this->get_baseurl());
	}

	function is_friendica_app() {
		return($this->is_friendica_app);
	}

	/**
	 * @brief Checks if the site is called via a backend process
	 *
	 * This isn't a perfect solution. But we need this check very early.
	 * So we cannot wait until the modules are loaded.
	 *
	 * @return bool Is it a known backend?
	 */
	function is_backend() {
		$backend = array();
		$backend[] = "_well_known";
		$backend[] = "api";
		$backend[] = "dfrn_notify";
		$backend[] = "fetch";
		$backend[] = "hcard";
		$backend[] = "hostxrd";
		$backend[] = "nodeinfo";
		$backend[] = "noscrape";
		$backend[] = "p";
		$backend[] = "poco";
		$backend[] = "post";
		$backend[] = "proxy";
		$backend[] = "pubsub";
		$backend[] = "pubsubhubbub";
		$backend[] = "receive";
		$backend[] = "rsd_xml";
		$backend[] = "salmon";
		$backend[] = "statistics_json";
		$backend[] = "xrd";

		if (in_array($this->module, $backend))
			return(true);
		else
			return($this->backend);
	}

	/**
	 * @brief Checks if the maximum number of database processes is reached
	 *
	 * @return bool Is the limit reached?
	 */
	function max_processes_reached() {

		// Is the function called statically?
		if (!is_object($this))
			return(self::$a->max_processes_reached());

		if ($this->is_backend()) {
			$process = "backend";
			$max_processes = get_config('system', 'max_processes_backend');
			if (intval($max_processes) == 0)
				$max_processes = 5;
		} else {
			$process = "frontend";
			$max_processes = get_config('system', 'max_processes_frontend');
			if (intval($max_processes) == 0)
				$max_processes = 20;
		}

		$processlist = dbm::processlist();
		if ($processlist["list"] != "") {
			logger("Processcheck: Processes: ".$processlist["amount"]." - Processlist: ".$processlist["list"], LOGGER_DEBUG);

			if ($processlist["amount"] > $max_processes) {
				logger("Processcheck: Maximum number of processes for ".$process." tasks (".$max_processes.") reached.", LOGGER_DEBUG);
				return true;
			}
		}
		return false;
	}

	/**
	 * @brief Checks if the maximum load is reached
	 *
	 * @return bool Is the load reached?
	 */
	function maxload_reached() {

		// Is the function called statically?
		if (!is_object($this))
			return(self::$a->maxload_reached());

		if ($this->is_backend()) {
			$process = "backend";
			$maxsysload = intval(get_config('system', 'maxloadavg'));
			if ($maxsysload < 1)
				$maxsysload = 50;
		} else {
			$process = "frontend";
			$maxsysload = intval(get_config('system','maxloadavg_frontend'));
			if ($maxsysload < 1)
				$maxsysload = 50;
		}

		$load = current_load();
		if ($load) {
			if (intval($load) > $maxsysload) {
				logger('system: load '.$load.' for '.$process.' tasks ('.$maxsysload.') too high.');
				return true;
			}
		}
		return false;
	}

	/**
	 * @brief Checks if the process is already running
	 *
	 * @param string $taskname The name of the task that will be used for the name of the lockfile
	 * @param string $task The path and name of the php script
	 * @param int $timeout The timeout after which a task should be killed
	 *
	 * @return bool Is the process running?
	 */
	function is_already_running($taskname, $task = "", $timeout = 540) {

		$lockpath = get_lockpath();
		if ($lockpath != '') {
			$pidfile = new pidfile($lockpath, $taskname);
			if ($pidfile->is_already_running()) {
				logger("Already running");
				if ($pidfile->running_time() > $timeout) {
					$pidfile->kill();
					logger("killed stale process");
					// Calling a new instance
					if ($task != "")
						proc_run(PRIORITY_MEDIUM, $task);
				}
				return true;
			}
		}
		return false;
	}

	function proc_run($args) {

		// Add the php path if it is a php call
		if (count($args) && ($args[0] === 'php' OR is_int($args[0]))) {

			// If the last worker fork was less than 10 seconds before then don't fork another one.
			// This should prevent the forking of masses of workers.
			if (get_config("system", "worker")) {
				if ((time() - get_config("system", "proc_run_started")) < 10)
					return;

				// Set the timestamp of the last proc_run
				set_config("system", "proc_run_started", time());
			}

			$args[0] = ((x($this->config,'php_path')) && (strlen($this->config['php_path'])) ? $this->config['php_path'] : 'php');
		}

		// add baseurl to args. cli scripts can't construct it
		$args[] = $this->get_baseurl();

		for($x = 0; $x < count($args); $x ++)
			$args[$x] = escapeshellarg($args[$x]);

		$cmdline = implode($args," ");

		if(get_config('system','proc_windows'))
			proc_close(proc_open('cmd /c start /b ' . $cmdline,array(),$foo,dirname(__FILE__)));
		else
			proc_close(proc_open($cmdline." &",array(),$foo,dirname(__FILE__)));

	}
}

/**
 * @brief Retrieve the App structure
 * 
 * Useful in functions which require it but don't get it passed to them
 */
function get_app() {
	global $a;
	return $a;
}


/**
 * @brief Multi-purpose function to check variable state.
 *
 * Usage: x($var) or $x($array, 'key')
 *
 * returns false if variable/key is not set
 * if variable is set, returns 1 if has 'non-zero' value, otherwise returns 0.
 * e.g. x('') or x(0) returns 0;
 *
 * @param string|array $s variable to check
 * @param string $k key inside the array to check
 *
 * @return bool|int
 */
function x($s,$k = NULL) {
	if($k != NULL) {
		if((is_array($s)) && (array_key_exists($k,$s))) {
			if($s[$k])
				return (int) 1;
			return (int) 0;
	}
		return false;
	}
	else {
		if(isset($s)) {
			if($s) {
				return (int) 1;
			}
			return (int) 0;
		}
		return false;
	}
}


/**
 * @brief Called from db initialisation if db is dead.
 */
function system_unavailable() {
	include('system_unavailable.php');
	system_down();
	killme();
}


function clean_urls() {
	global $a;
	//	if($a->config['system']['clean_urls'])
	return true;
	//	return false;
}

function z_path() {
	global $a;
	$base = $a->get_baseurl();
	if(! clean_urls())
		$base .= '/?q=';
	return $base;
}

/**
 * @brief Returns the baseurl.
 *
 * @see App::get_baseurl()
 *
 * @return string
 */
function z_root() {
	global $a;
	return $a->get_baseurl();
}

/**
 * @brief Return absolut URL for given $path.
 *
 * @param string $path
 *
 * @return string
 */
function absurl($path) {
	if(strpos($path,'/') === 0)
		return z_path() . $path;
	return $path;
}

/**
 * @brief Function to check if request was an AJAX (xmlhttprequest) request.
 *
 * @return boolean
 */
function is_ajax() {
	return (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest');
}

function check_db() {

	$build = get_config('system','build');
	if(! x($build)) {
		set_config('system','build',DB_UPDATE_VERSION);
		$build = DB_UPDATE_VERSION;
	}
	if($build != DB_UPDATE_VERSION)
		proc_run(PRIORITY_SYSTEM, 'include/dbupdate.php');

}


/**
 * Sets the base url for use in cmdline programs which don't have
 * $_SERVER variables
 */
function check_url(&$a) {

	$url = get_config('system','url');

	// if the url isn't set or the stored url is radically different
	// than the currently visited url, store the current value accordingly.
	// "Radically different" ignores common variations such as http vs https
	// and www.example.com vs example.com.
	// We will only change the url to an ip address if there is no existing setting

	if(! x($url))
		$url = set_config('system','url',$a->get_baseurl());
	if((! link_compare($url,$a->get_baseurl())) && (! preg_match("/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/",$a->get_hostname)))
		$url = set_config('system','url',$a->get_baseurl());

	return;
}


/**
 * @brief Automatic database updates
 */
function update_db(&$a) {
	$build = get_config('system','build');
	if(! x($build))
		$build = set_config('system','build',DB_UPDATE_VERSION);

	if($build != DB_UPDATE_VERSION) {
		$stored = intval($build);
		$current = intval(DB_UPDATE_VERSION);
		if($stored < $current) {
			load_config('database');

			// We're reporting a different version than what is currently installed.
			// Run any existing update scripts to bring the database up to current.

			// make sure that boot.php and update.php are the same release, we might be
			// updating right this very second and the correct version of the update.php
			// file may not be here yet. This can happen on a very busy site.

			if(DB_UPDATE_VERSION == UPDATE_VERSION) {
				// Compare the current structure with the defined structure

				$t = get_config('database','dbupdate_'.DB_UPDATE_VERSION);
				if($t !== false)
					return;

				set_config('database','dbupdate_'.DB_UPDATE_VERSION, time());

				// run old update routine (wich could modify the schema and
				// conflits with new routine)
				for ($x = $stored; $x < NEW_UPDATE_ROUTINE_VERSION; $x++) {
					$r = run_update_function($x);
					if (!$r) break;
				}
				if ($stored < NEW_UPDATE_ROUTINE_VERSION) $stored = NEW_UPDATE_ROUTINE_VERSION;


				// run new update routine
				// it update the structure in one call
				$retval = update_structure(false, true);
				if($retval) {
					update_fail(
						DB_UPDATE_VERSION,
						$retval
					);
					return;
				} else {
					set_config('database','dbupdate_'.DB_UPDATE_VERSION, 'success');
				}

				// run any left update_nnnn functions in update.php
				for($x = $stored; $x < $current; $x ++) {
					$r = run_update_function($x);
					if (!$r) break;
				}
			}
		}
	}

	return;
}

function run_update_function($x) {
	if(function_exists('update_' . $x)) {

		// There could be a lot of processes running or about to run.
		// We want exactly one process to run the update command.
		// So store the fact that we're taking responsibility
		// after first checking to see if somebody else already has.

		// If the update fails or times-out completely you may need to
		// delete the config entry to try again.

		$t = get_config('database','update_' . $x);
		if($t !== false)
			return false;
		set_config('database','update_' . $x, time());

		// call the specific update

		$func = 'update_' . $x;
		$retval = $func();

		if($retval) {
			//send the administrator an e-mail
			update_fail(
				$x,
				sprintf(t('Update %s failed. See error logs.'), $x)
			);
			return false;
		} else {
			set_config('database','update_' . $x, 'success');
			set_config('system','build', $x + 1);
			return true;
		}
	} else {
		set_config('database','update_' . $x, 'success');
		set_config('system','build', $x + 1);
		return true;
	}
	return true;
}

/**
 * @brief Synchronise plugins:
 *
 * $a->config['system']['addon'] contains a comma-separated list of names
 * of plugins/addons which are used on this system.
 * Go through the database list of already installed addons, and if we have
 * an entry, but it isn't in the config list, call the uninstall procedure
 * and mark it uninstalled in the database (for now we'll remove it).
 * Then go through the config list and if we have a plugin that isn't installed,
 * call the install procedure and add it to the database.
 * 
 * @param App $a
 *
	 */
function check_plugins(&$a) {

	$r = q("SELECT * FROM `addon` WHERE `installed` = 1");
	if(dbm::is_result($r))
		$installed = $r;
	else
		$installed = array();

	$plugins = get_config('system','addon');
	$plugins_arr = array();

	if($plugins)
		$plugins_arr = explode(',',str_replace(' ', '',$plugins));

	$a->plugins = $plugins_arr;

	$installed_arr = array();

	if(count($installed)) {
		foreach($installed as $i) {
			if(! in_array($i['name'],$plugins_arr)) {
				uninstall_plugin($i['name']);
			}
			else {
				$installed_arr[] = $i['name'];
			}
		}
	}

	if(count($plugins_arr)) {
		foreach($plugins_arr as $p) {
			if(! in_array($p,$installed_arr)) {
				install_plugin($p);
			}
		}
	}


	load_hooks();

	return;
}

function get_guid($size=16, $prefix = "") {

	if ($prefix == "") {
		$a = get_app();
		$prefix = hash("crc32", $a->get_hostname());
	}

	while (strlen($prefix) < ($size - 13))
		$prefix .= mt_rand();

	if ($size >= 24) {
		$prefix = substr($prefix, 0, $size - 22);
		return(str_replace(".", "", uniqid($prefix, true)));
	} else {
		$prefix = substr($prefix, 0, max($size - 13, 0));
		return(uniqid($prefix));
	}
}

/** 
 * @brief Wrapper for adding a login box.
 * 
 * @param bool $register
 *	If $register == true provide a registration link.
 *	This will most always depend on the value of $a->config['register_policy'].
 * @param bool $hiddens
 * 
 * @return string
 *	Returns the complete html for inserting into the page
 * 
 * @hooks 'login_hook'
 *	string $o
 */
function login($register = false, $hiddens=false) {
	$a = get_app();
	$o = "";
	$reg = false;
	if ($register) {
		$reg = array(
			'title' => t('Create a New Account'),
			'desc' => t('Register')
		);
	}

	$noid = get_config('system','no_openid');

	$dest_url = $a->query_string;

	if(local_user()) {
		$tpl = get_markup_template("logout.tpl");
	}
	else {
		$a->page['htmlhead'] .= replace_macros(get_markup_template("login_head.tpl"),array(
			'$baseurl'		=> $a->get_baseurl(true)
		));

		$tpl = get_markup_template("login.tpl");
		$_SESSION['return_url'] = $a->query_string;
		$a->module = 'login';
	}

	$o .= replace_macros($tpl, array(

		'$dest_url'	=> $dest_url,
		'$logout'	=> t('Logout'),
		'$login'	=> t('Login'),

		'$lname'	=> array('username', t('Nickname or Email: ') , '', ''),
		'$lpassword' 	=> array('password', t('Password: '), '', ''),
		'$lremember'	=> array('remember', t('Remember me'), 0,  ''),

		'$openid'	=> !$noid,
		'$lopenid'	=> array('openid_url', t('Or login using OpenID: '),'',''),

		'$hiddens'	=> $hiddens,

		'$register'	=> $reg,

		'$lostpass'     => t('Forgot your password?'),
		'$lostlink'     => t('Password Reset'),

		'$tostitle'	=> t('Website Terms of Service'),
		'$toslink'	=> t('terms of service'),

		'$privacytitle'	=> t('Website Privacy Policy'),
		'$privacylink'	=> t('privacy policy'),

	));

	call_hooks('login_hook',$o);

	return $o;
}

/**
 * @brief Used to end the current process, after saving session state.
 */
function killme() {
	if (!get_app()->is_backend())
		session_write_close();

	exit;
}

/**
 * @brief Redirect to another URL and terminate this process.
 */
function goaway($s) {
	if (!strstr(normalise_link($s), "http://"))
		$s = App::get_baseurl()."/".$s;

	header("Location: $s");
	killme();
}


/**
 * @brief Returns the user id of locally logged in user or false.
 * 
 * @return int|bool user id or false
 */
function local_user() {
	if((x($_SESSION,'authenticated')) && (x($_SESSION,'uid')))
		return intval($_SESSION['uid']);
	return false;
}

/**
 * @brief Returns contact id of authenticated site visitor or false
 * 
 * @return int|bool visitor_id or false
 */
function remote_user() {
	if((x($_SESSION,'authenticated')) && (x($_SESSION,'visitor_id')))
		return intval($_SESSION['visitor_id']);
	return false;
}

/**
 * @brief Show an error message to user.
 *
 * This function save text in session, to be shown to the user at next page load
 *
 * @param string $s - Text of notice
 */
function notice($s) {
	$a = get_app();
	if(! x($_SESSION,'sysmsg'))	$_SESSION['sysmsg'] = array();
	if($a->interactive)
		$_SESSION['sysmsg'][] = $s;
}

/**
 * @brief Show an info message to user.
 *
 * This function save text in session, to be shown to the user at next page load
 *
 * @param string $s - Text of notice
 */
function info($s) {
	$a = get_app();

	if (local_user() AND get_pconfig(local_user(),'system','ignore_info'))
		return;

	if(! x($_SESSION,'sysmsg_info')) $_SESSION['sysmsg_info'] = array();
	if($a->interactive)
		$_SESSION['sysmsg_info'][] = $s;
}


/**
 * @brief Wrapper around config to limit the text length of an incoming message
 *
 * @return int
 */
function get_max_import_size() {
	global $a;
	return ((x($a->config,'max_import_size')) ? $a->config['max_import_size'] : 0 );
}

/**
 * @brief Wrap calls to proc_close(proc_open()) and call hook
 *	so plugins can take part in process :)
 *
 * @param (string|integer) $cmd program to run or priority
 * 
 * next args are passed as $cmd command line
 * e.g.: proc_run("ls","-la","/tmp");
 * or: proc_run(PRIORITY_HIGH, "include/notifier.php", "drop", $drop_id);
 *
 * @note $cmd and string args are surrounded with ""
 * 
 * @hooks 'proc_run'
 *	array $arr
 */
function proc_run($cmd){

	$a = get_app();

	$args = func_get_args();

	$newargs = array();
	if (!count($args))
		return;

	// expand any arrays

	foreach($args as $arg) {
		if(is_array($arg)) {
			foreach($arg as $n) {
				$newargs[] = $n;
			}
		} else
			$newargs[] = $arg;
	}

	$args = $newargs;

	$arr = array('args' => $args, 'run_cmd' => true);

	call_hooks("proc_run", $arr);
	if (!$arr['run_cmd'] OR !count($args))
		return;

	if (!get_config("system", "worker") OR
		(($args[0] != 'php') AND !is_int($args[0]))) {
		$a->proc_run($args);
		return;
	}

	if (is_int($args[0]))
		$priority = $args[0];
	else
		$priority = PRIORITY_MEDIUM;

	$argv = $args;
	array_shift($argv);

	$parameters = json_encode($argv);
	$found = q("SELECT `id` FROM `workerqueue` WHERE `parameter` = '%s'",
		dbesc($parameters));

	if (!$found)
		q("INSERT INTO `workerqueue` (`parameter`, `created`, `priority`)
			VALUES ('%s', '%s', %d)",
			dbesc($parameters),
			dbesc(datetime_convert()),
			intval($priority));

	// Should we quit and wait for the poller to be called as a cronjob?
	if (get_config("system", "worker_dont_fork"))
		return;

	// Checking number of workers
	$workers = q("SELECT COUNT(*) AS `workers` FROM `workerqueue` WHERE `executed` != '0000-00-00 00:00:00'");

	// Get number of allowed number of worker threads
	$queues = intval(get_config("system", "worker_queues"));

	if ($queues == 0)
		$queues = 4;

	// If there are already enough workers running, don't fork another one
	if ($workers[0]["workers"] >= $queues)
		return;

	// Now call the poller to execute the jobs that we just added to the queue
	$args = array("php", "include/poller.php", "no_cron");

	$a->proc_run($args);
}

function current_theme(){
	$app_base_themes = array('duepuntozero', 'dispy', 'quattro');

	$a = get_app();

	$page_theme = null;

	// Find the theme that belongs to the user whose stuff we are looking at

	if($a->profile_uid && ($a->profile_uid != local_user())) {
		$r = q("select theme from user where uid = %d limit 1",
			intval($a->profile_uid)
		);
		if(dbm::is_result($r))
			$page_theme = $r[0]['theme'];
	}

	// Allow folks to over-rule user themes and always use their own on their own site.
	// This works only if the user is on the same server

	if($page_theme && local_user() && (local_user() != $a->profile_uid)) {
		if(get_pconfig(local_user(),'system','always_my_theme'))
			$page_theme = null;
	}

//		$mobile_detect = new Mobile_Detect();
//		$is_mobile = $mobile_detect->isMobile() || $mobile_detect->isTablet();
	$is_mobile = $a->is_mobile || $a->is_tablet;

	$standard_system_theme = ((isset($a->config['system']['theme'])) ? $a->config['system']['theme'] : '');
	$standard_theme_name = ((isset($_SESSION) && x($_SESSION,'theme')) ? $_SESSION['theme'] : $standard_system_theme);

	if($is_mobile) {
		if(isset($_SESSION['show-mobile']) && !$_SESSION['show-mobile']) {
			$system_theme = $standard_system_theme;
			$theme_name = $standard_theme_name;
		}
		else {
			$system_theme = ((isset($a->config['system']['mobile-theme'])) ? $a->config['system']['mobile-theme'] : $standard_system_theme);
			$theme_name = ((isset($_SESSION) && x($_SESSION,'mobile-theme')) ? $_SESSION['mobile-theme'] : $system_theme);

			if($theme_name === '---') {
				// user has selected to have the mobile theme be the same as the normal one
				$system_theme = $standard_system_theme;
				$theme_name = $standard_theme_name;

				if($page_theme)
					$theme_name = $page_theme;
			}
		}
	}
	else {
		$system_theme = $standard_system_theme;
		$theme_name = $standard_theme_name;

		if($page_theme)
			$theme_name = $page_theme;
	}

	if($theme_name &&
			(file_exists('view/theme/' . $theme_name . '/style.css') ||
					file_exists('view/theme/' . $theme_name . '/style.php')))
		return($theme_name);

	foreach($app_base_themes as $t) {
		if(file_exists('view/theme/' . $t . '/style.css')||
				file_exists('view/theme/' . $t . '/style.php'))
			return($t);
	}

	$fallback = array_merge(glob('view/theme/*/style.css'),glob('view/theme/*/style.php'));
	if(count($fallback))
		return (str_replace('view/theme/','', substr($fallback[0],0,-10)));

}

/**
 * @brief Return full URL to theme which is currently in effect.
 * 
 * Provide a sane default if nothing is chosen or the specified theme does not exist.
 * 
 * @return string
 */
function current_theme_url() {
	global $a;

	$t = current_theme();

	$opts = (($a->profile_uid) ? '?f=&puid=' . $a->profile_uid : '');
	if (file_exists('view/theme/' . $t . '/style.php'))
		return('view/theme/'.$t.'/style.pcss'.$opts);

	return('view/theme/'.$t.'/style.css');
}

function feed_birthday($uid,$tz) {

	/**
	 *
	 * Determine the next birthday, but only if the birthday is published
	 * in the default profile. We _could_ also look for a private profile that the
	 * recipient can see, but somebody could get mad at us if they start getting
	 * public birthday greetings when they haven't made this info public.
	 *
	 * Assuming we are able to publish this info, we are then going to convert
	 * the start time from the owner's timezone to UTC.
	 *
	 * This will potentially solve the problem found with some social networks
	 * where birthdays are converted to the viewer's timezone and salutations from
	 * elsewhere in the world show up on the wrong day. We will convert it to the
	 * viewer's timezone also, but first we are going to convert it from the birthday
	 * person's timezone to GMT - so the viewer may find the birthday starting at
	 * 6:00PM the day before, but that will correspond to midnight to the birthday person.
	 *
	 */


	$birthday = '';

	if(! strlen($tz))
		$tz = 'UTC';

	$p = q("SELECT `dob` FROM `profile` WHERE `is-default` = 1 AND `uid` = %d LIMIT 1",
			intval($uid)
	);

	if(dbm::is_result($p)) {
		$tmp_dob = substr($p[0]['dob'],5);
		if(intval($tmp_dob)) {
			$y = datetime_convert($tz,$tz,'now','Y');
			$bd = $y . '-' . $tmp_dob . ' 00:00';
			$t_dob = strtotime($bd);
			$now = strtotime(datetime_convert($tz,$tz,'now'));
			if($t_dob < $now)
				$bd = $y + 1 . '-' . $tmp_dob . ' 00:00';
			$birthday = datetime_convert($tz,'UTC',$bd,ATOM_TIME);
		}
	}

	return $birthday;
}

/**
 * @brief Check if current user has admin role.
 *
 * @return bool true if user is an admin
 */
function is_site_admin() {
	$a = get_app();

	$adminlist = explode(",", str_replace(" ", "", $a->config['admin_email']));

	//if(local_user() && x($a->user,'email') && x($a->config,'admin_email') && ($a->user['email'] === $a->config['admin_email']))
	if(local_user() && x($a->user,'email') && x($a->config,'admin_email') && in_array($a->user['email'], $adminlist))
		return true;
	return false;
}

/**
 * @brief Returns querystring as string from a mapped array.
 *
 * @param array $params mapped array with query parameters
 * @param string $name of parameter, default null
 *
 * @return string
 */
function build_querystring($params, $name=null) {
	$ret = "";
	foreach($params as $key=>$val) {
		if(is_array($val)) {
			if($name==null) {
				$ret .= build_querystring($val, $key);
			} else {
				$ret .= build_querystring($val, $name."[$key]");
			}
		} else {
			$val = urlencode($val);
			if($name!=null) {
				$ret.=$name."[$key]"."=$val&";
			} else {
				$ret.= "$key=$val&";
			}
		}
	}
	return $ret;
}

function explode_querystring($query) {
	$arg_st = strpos($query, '?');
	if($arg_st !== false) {
		$base = substr($query, 0, $arg_st);
		$arg_st += 1;
	} else {
		$base = '';
		$arg_st = 0;
	}

	$args = explode('&', substr($query, $arg_st));
	foreach($args as $k=>$arg) {
		if($arg === '')
			unset($args[$k]);
	}
	$args = array_values($args);

	if(!$base) {
		$base = $args[0];
		unset($args[0]);
		$args = array_values($args);
	}

	return array(
		'base' => $base,
		'args' => $args,
	);
}

/**
* Returns the complete URL of the current page, e.g.: http(s)://something.com/network
*
* Taken from http://webcheatsheet.com/php/get_current_page_url.php
*/
function curPageURL() {
	$pageURL = 'http';
	if ($_SERVER["HTTPS"] == "on") {$pageURL .= "s";}
	$pageURL .= "://";
	if ($_SERVER["SERVER_PORT"] != "80" && $_SERVER["SERVER_PORT"] != "443") {
		$pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
	} else {
		$pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
	}
	return $pageURL;
}

function random_digits($digits) {
	$rn = '';
	for($i = 0; $i < $digits; $i++) {
		$rn .= rand(0,9);
	}
	return $rn;
}

function get_server() {
	$server = get_config("system", "directory");

	if ($server == "")
		$server = "http://dir.friendi.ca";

	return($server);
}

function get_cachefile($file, $writemode = true) {
	$cache = get_itemcachepath();

	if ((! $cache) || (! is_dir($cache)))
		return("");

	$subfolder = $cache."/".substr($file, 0, 2);

	$cachepath = $subfolder."/".$file;

	if ($writemode) {
		if (!is_dir($subfolder)) {
			mkdir($subfolder);
			chmod($subfolder, 0777);
		}
	}

	return($cachepath);
}

function clear_cache($basepath = "", $path = "") {
	if ($path == "") {
		$basepath = get_itemcachepath();
		$path = $basepath;
	}

	if (($path == "") OR (!is_dir($path)))
		return;

	if (substr(realpath($path), 0, strlen($basepath)) != $basepath)
		return;

	$cachetime = (int)get_config('system','itemcache_duration');
	if ($cachetime == 0)
		$cachetime = 86400;

	if (is_writable($path)){
		if ($dh = opendir($path)) {
			while (($file = readdir($dh)) !== false) {
				$fullpath = $path."/".$file;
				if ((filetype($fullpath) == "dir") and ($file != ".") and ($file != ".."))
					clear_cache($basepath, $fullpath);
				if ((filetype($fullpath) == "file") and (filectime($fullpath) < (time() - $cachetime)))
					unlink($fullpath);
			}
			closedir($dh);
		}
	}
}

function get_itemcachepath() {
	// Checking, if the cache is deactivated
	$cachetime = (int)get_config('system','itemcache_duration');
	if ($cachetime < 0)
		return "";

	$itemcache = get_config('system','itemcache');
	if (($itemcache != "") AND is_dir($itemcache) AND is_writable($itemcache))
		return($itemcache);

	$temppath = get_temppath();

	if ($temppath != "") {
		$itemcache = $temppath."/itemcache";
		if(!file_exists($itemcache) && !is_dir($itemcache)) {
			mkdir($itemcache);
		}

		if (is_dir($itemcache) AND is_writable($itemcache)) {
			set_config("system", "itemcache", $itemcache);
			return($itemcache);
		}
	}
	return "";
}

function get_lockpath() {
	$lockpath = get_config('system','lockpath');
	if (($lockpath != "") AND is_dir($lockpath) AND is_writable($lockpath))
		return($lockpath);

	$temppath = get_temppath();

	if ($temppath != "") {
		$lockpath = $temppath."/lock";

		if (!is_dir($lockpath))
			mkdir($lockpath);
		elseif (!is_writable($lockpath))
			$lockpath = $temppath;

		if (is_dir($lockpath) AND is_writable($lockpath)) {
			set_config("system", "lockpath", $lockpath);
			return($lockpath);
		}
	}
	return "";
}

function get_temppath() {
	$a = get_app();

	$temppath = get_config("system","temppath");
	if (($temppath != "") AND is_dir($temppath) AND is_writable($temppath))
		return($temppath);

	$temppath = sys_get_temp_dir();
	if (($temppath != "") AND is_dir($temppath) AND is_writable($temppath)) {
		$temppath .= "/".$a->get_hostname();
		if (!is_dir($temppath))
			mkdir($temppath);

		if (is_dir($temppath) AND is_writable($temppath)) {
			set_config("system", "temppath", $temppath);
			return($temppath);
		}
	}

	return("");
}

function set_template_engine(&$a, $engine = 'internal') {
/// @note This function is no longer necessary, but keep it as a wrapper to the class method
/// to avoid breaking themes again unnecessarily

	$a->set_template_engine($engine);
}

if(!function_exists('exif_imagetype')) {
	function exif_imagetype($file) {
		$size = getimagesize($file);
		return($size[2]);
	}
}

function validate_include(&$file) {
	$orig_file = $file;

	$file = realpath($file);

	if (strpos($file, getcwd()) !== 0)
		return false;

	$file = str_replace(getcwd()."/", "", $file, $count);
	if ($count != 1)
		return false;

	if ($orig_file !== $file)
		return false;

	$valid = false;
	if (strpos($file, "include/") === 0)
		$valid = true;

	if (strpos($file, "addon/") === 0)
		$valid = true;

	if (!$valid)
		return false;

	return true;
}

function current_load() {
	if (!function_exists('sys_getloadavg'))
		return false;

	$load_arr = sys_getloadavg();

	if (!is_array($load_arr))
		return false;

	return max($load_arr[0], $load_arr[1]);
}

/**
 * @brief get c-style args
 * 
 * @return int
 */
function argc() {
	return get_app()->argc;
}

/**
 * @brief Returns the value of a argv key
 * 
 * @param int $x argv key
 * @return string Value of the argv key
 */
function argv($x) {
	if(array_key_exists($x,get_app()->argv))
		return get_app()->argv[$x];

	return '';
}

/**
 * @brief Get the data which is needed for infinite scroll
 * 
 * For invinite scroll we need the page number of the actual page
 * and the the URI where the content of the next page comes from.
 * This data is needed for the js part in main.js.
 * Note: infinite scroll does only work for the network page (module)
 * 
 * @param string $module The name of the module (e.g. "network")
 * @return array Of infinite scroll data
 *	'pageno' => $pageno The number of the actual page
 *	'reload_uri' => $reload_uri The URI of the content we have to load
 */
function infinite_scroll_data($module) {

	if (get_pconfig(local_user(),'system','infinite_scroll')
		AND ($module == "network") AND ($_GET["mode"] != "minimal")) {

		// get the page number
		if (is_string($_GET["page"]))
			$pageno = $_GET["page"];
		else
			$pageno = 1;

		$reload_uri = "";

		// try to get the uri from which we load the content
		foreach ($_GET AS $param => $value)
			if (($param != "page") AND ($param != "q"))
				$reload_uri .= "&".$param."=".urlencode($value);

		if (($a->page_offset != "") AND !strstr($reload_uri, "&offset="))
			$reload_uri .= "&offset=".urlencode($a->page_offset);

		$arr = array("pageno" => $pageno, "reload_uri" => $reload_uri);

		return $arr;
	}
}