Version 4.5.0

system/Output/Output.php

@@ -11,7 +11,7 @@
 namespace IPS;
 
 /* To prevent PHP errors (extending class does not exist) revealing path */
-if ( !defined( '\IPS\SUITE_UNIQUE_KEY' ) )
+if ( !\defined( '\IPS\SUITE_UNIQUE_KEY' ) )
 {
 	header( ( isset( $_SERVER['SERVER_PROTOCOL'] ) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0' ) . ' 403 Forbidden' );
 	exit;
@@ -24,7 +24,7 @@ class _Output
 {
 	/**
 	 * @brief	HTTP Statuses
-	 * @link	http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
+	 * @see		<a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html">RFC 2616</a>
 	 */
 	public static $httpStatuses = array( 100 => 'Continue', 101 => 'Switching Protocols', 200 => 'OK', 201 => 'Created', 202 => 'Accepted', 203 => 'Non-Authoritative Information', 204 => 'No Content', 205 => 'Reset Content', 206 => 'Partial Content', 300 => 'Multiple Choices', 301 => 'Moved Permanently', 302 => 'Found', 303 => 'See Other', 304 => 'Not Modified', 305 => 'Use Proxy', 307 => 'Temporary Redirect', 400 => 'Bad Request', 401 => 'Unauthorized', 402 => 'Payment Required', 403 => 'Forbidden', 404 => 'Not Found', 405 => 'Method Not Allowed', 406 => 'Not Acceptable', 407 => 'Proxy Authentication Required', 408 => 'Request Timeout', 409 => 'Conflict', 410 => 'Gone', 411 => 'Length Required', 412 => 'Precondition Failed', 413 => 'Request Entity Too Large', 414 => 'Request-URI Too Long', 415 => 'Unsupported Media Type', 416 => 'Requested Range Not Satisfiable', 417 => 'Expectation Failed', 429 => 'Too Many Requests', 500 => 'Internal Server Error', 501 => 'Not Implemented', 502 => 'Bad Gateway', 503 => 'Service Unavailable', 504 => 'Gateway Timeout', 505 => 'HTTP Version Not Supported' );
 	
@@ -43,7 +43,7 @@ class _Output
 	 */
 	protected static $javascriptObjects = null;
 	
-		/**
+	/**
 	 * @brief	File object classes
 	 */
 	protected static $fileObjectClasses = array();
@@ -52,9 +52,19 @@ class _Output
 	 * @brief	Meta tags for the current page
 	 */
 	public $metaTags	= array();
+
+	/**
+	 * @brief	Custom meta tags for the current page
+	 */
+	public $customMetaTags	= array();
+
+	/**
+	 * @brief	Automatic meta tags for the current page
+	 */
+	public $autoMetaTags	= array();
 	
 	/**
-	 * @brief	Other <link rel=""> tags
+	 * @brief	Other `<link rel="">` tags
 	 */
 	public $linkTags = array();
 	
@@ -82,17 +92,17 @@ class _Output
 	{
 		if( static::$instance === NULL )
 		{
-			$classname = get_called_class();
+			$classname = \get_called_class();
 			static::$instance = new $classname;
 		}
 		
 		/* Inline Message */
-		if( isset( $_SESSION['inlineMessage'] ) )
+		if( $message = static::getInlineMessage() )
 		{
 			if( !\IPS\Request::i()->isAjax() )
 			{
-				static::$instance->inlineMessage = $_SESSION['inlineMessage'];
-				$_SESSION['inlineMessage'] = NULL;
+				static::$instance->inlineMessage = $message;
+				static::setInlineMessage();
 			}
 		}
 
@@ -111,6 +121,11 @@ class _Output
 	 */
 	public $title = '';
 
+	/**
+	 * @brief	Default page title (may differ from $title if the meta tag editor was used)
+	 */
+	public $defaultPageTitle = '';
+
 	/**
 	 * @brief	Should the title show in the header (ACP only)?
 	 */
@@ -142,7 +157,7 @@ class _Output
 	public $jsVars = array();
 	
 	/**
-	 * @brief	Other raw JS - this is included inside an existing <script> tag already, so you should omit wrapping tags
+	 * @brief	Other raw JS - this is included inside an existing `<script>` tag already, so you should omit wrapping tags
 	 */
 	public $headJs = '';
 
@@ -152,7 +167,7 @@ class _Output
 	public $headCss = '';
 
 	/**
-	 * @brief	Anything set in this property will be output right before </body> - useful for certain third party scripts that need to be output at end of page
+	 * @brief	Anything set in this property will be output right before `</body>` - useful for certain third party scripts that need to be output at end of page
 	 */
 	public $endBodyCode = '';
 	
@@ -197,7 +212,7 @@ class _Output
 	public $editUrl	= NULL;
 	
 	/**
-	 * @brief	<base target="">
+	 * @brief	`<base target="">`
 	 */
 	public $base	= NULL;
 	
@@ -211,15 +226,36 @@ class _Output
 	 */
 	public $pageCaching = TRUE;
 	
+	/**
+	 * Constructor
+	 *
+	 * @return	void
+	 */
+	public function __construct()
+	{
+		if ( \IPS\Dispatcher::hasInstance() and \IPS\Dispatcher::i()->controllerLocation !== 'setup' )
+		{
+			if ( \IPS\Settings::i()->clickjackprevention == 'csp' )
+			{
+				$this->httpHeaders['Content-Security-Policy'] = \IPS\Settings::i()->csp_header;
+				$this->httpHeaders['X-Content-Security-Policy'] = \IPS\Settings::i()->csp_header; // This is just for IE11
+			}
+			elseif ( \IPS\Settings::i()->clickjackprevention != 'none' )
+			{
+				$this->httpHeaders['X-Frame-Options'] = 'sameorigin';
+			}
+		}
+	}
+	
 	/**
 	 * Get a JS bundle
 	 *
-	 * JS Bundle Cheatsheet
-	 * library.js (this is jQuery, mustache, underscore, jstz, etc)
-	 * framework.js (this is ui/*, utils/*, ips.model.js, ips.controller.js and the editor controllers)
-     * admin.js or front.js (these are controllers, templates and models which are used everywhere for that location)
-	 * app.js (this is all models for a single application)
-	 * {location}_{section}.js (this is all controllers and templates for this section called ad-hoc when needed)
+	 * @par JS Bundle Cheatsheet
+	 * @li library.js (this is jQuery, mustache, underscore, jstz, etc)
+	 * @li framework.js (this is ui/, utils/*, ips.model.js, ips.controller.js and the editor controllers)
+     * @li admin.js or front.js (these are controllers, templates and models which are used everywhere for that location)
+	 * @li app.js (this is all models for a single application)
+	 * @li {location}_{section}.js (this is all controllers and templates for this section called ad-hoc when needed)
 	 *
 	 * @param	string		$file		Filename
 	 * @param	string|null	$app		Application
@@ -232,7 +268,7 @@ class _Output
 			 
 		if ( $location === 'interface' AND mb_substr( $file, -3 ) === '.js' )
 		{
-			return array( rtrim( \IPS\Http\Url::baseUrl( \IPS\Http\Url::PROTOCOL_RELATIVE ), '/' ) . "/applications/{$app}/interface/{$file}?v=" . ( defined( '\IPS\CACHEBUST_KEY' ) ? \IPS\CACHEBUST_KEY : time() ) );
+			return array( rtrim( \IPS\Http\Url::baseUrl( \IPS\Http\Url::PROTOCOL_RELATIVE ), '/' ) . "/applications/{$app}/interface/{$file}?v=" . ( \defined( '\IPS\CACHEBUST_KEY' ) ? \IPS\CACHEBUST_KEY : time() ) );
 		}
 		elseif ( \IPS\IN_DEV )
 		{
@@ -240,14 +276,14 @@ class _Output
 		}
 		else
 		{
-			if ( class_exists( 'IPS\Dispatcher', FALSE ) and \IPS\Dispatcher::i()->controllerLocation === 'setup' )
+			if ( class_exists( 'IPS\Dispatcher', FALSE ) and ( !\IPS\Dispatcher::hasInstance() OR \IPS\Dispatcher::i()->controllerLocation === 'setup' ) )
 			{
 				return array();
 			}
 			
 			if ( $app === null OR $app === 'global' )
 			{
-				if ( in_array( $file, static::$globalJavascript ) )
+				if ( \in_array( $file, static::$globalJavascript ) )
 				{
 					/* Global bundle (admin.js, front.js, library.js, framework.js, map.js) */
 					return array( static::_getJavascriptFileObject( 'global', 'root', $file )->url );
@@ -347,7 +383,7 @@ class _Output
 		{
 			$key = md5( $app .'-' . $location . '-' . $file );
 			
-			if ( isset( $javascriptObjects[ $app ] ) and is_array( $javascriptObjects[ $app ] ) and in_array( $key, array_keys( $javascriptObjects[ $app ] ) ) )
+			if ( isset( $javascriptObjects[ $app ] ) and \is_array( $javascriptObjects[ $app ] ) and \in_array( $key, array_keys( $javascriptObjects[ $app ] ) ) )
 			{
 				if ( $javascriptObjects[ $app ][ $key ] !== NULL )
 				{
@@ -357,7 +393,9 @@ class _Output
 				}
 			}
 		}
-		
+
+		\IPS\Settings::i()->changeValues( array( 'javascript_updated' => time() ) );
+
 		\IPS\Data\Store::i()->javascript_map = $javascriptObjects;
 	}
 
@@ -460,7 +498,7 @@ class _Output
 
 		$javascriptObjects = ( isset( \IPS\Data\Store::i()->javascript_map ) ) ? \IPS\Data\Store::i()->javascript_map : array();
 
-		if ( isset( $javascriptObjects[ $app ] ) and in_array( $key, array_keys( $javascriptObjects[ $app ] ) ) )
+		if ( isset( $javascriptObjects[ $app ] ) and \in_array( $key, array_keys( $javascriptObjects[ $app ] ) ) )
 		{
 			if ( $javascriptObjects[ $app ][ $key ] === NULL )
 			{
@@ -499,7 +537,7 @@ class _Output
 		$javascriptObjects = ( isset( \IPS\Data\Store::i()->javascript_map ) ) ? \IPS\Data\Store::i()->javascript_map : array();
 		
 		/* Test again */
-		if ( isset( $javascriptObjects[ $app ] ) and in_array( $key, array_keys( $javascriptObjects[ $app ] ) ) and $javascriptObjects[ $app ][ $key ] )
+		if ( isset( $javascriptObjects[ $app ] ) and \in_array( $key, array_keys( $javascriptObjects[ $app ] ) ) and $javascriptObjects[ $app ][ $key ] )
 		{
 			return \IPS\File::get( 'core_Theme', $javascriptObjects[ $app ][ $key ] );
 		}
@@ -545,6 +583,12 @@ class _Output
 		{
 			\IPS\Output::i()->redirect( \IPS\Http\Url::internal( "app=core&module=system&controller=login", 'front', 'login' )->setQueryString( '_mfaLogin', 1 ) );
 		}
+
+		/* Do not show advertisements that shouldn't display on non-content pages on error pages */
+		if( \IPS\Dispatcher::i()->dispatcherController )
+		{
+			\IPS\Dispatcher::i()->dispatcherController->isContentPage = FALSE;
+		}
 		
 		/* If we're in an external script, just show a simple message */
 		if ( !\IPS\Dispatcher::hasInstance() )
@@ -594,7 +638,7 @@ class _Output
 		\IPS\Member::loggedIn()->language()->parseOutputForDisplay( $message );
 								
 		/* Log */
-		$level = intval( \substr( $code, 0, 1 ) );
+		$level = \intval( \substr( $code, 0, 1 ) );
 		if( !\IPS\Session::i()->userAgent->spider )
 		{
 			if( $code and \IPS\Settings::i()->error_log_level and $level >= \IPS\Settings::i()->error_log_level )
@@ -607,11 +651,8 @@ class _Output
 					'log_ip_address'	=> \IPS\Request::i()->ipAddress(),
 					'log_request_uri'	=> $_SERVER['REQUEST_URI'],
 					) );
-			}
 
-			if( \IPS\Settings::i()->error_notify_level and $level >= \IPS\Settings::i()->error_notify_level )
-			{
-				\IPS\Email::buildFromTemplate( 'core', 'error_log', array( $code, $message ), \IPS\Email::TYPE_TRANSACTIONAL )->send( \IPS\Settings::i()->email_in );
+				\IPS\core\AdminNotification::send( 'core', 'Error', NULL, TRUE, array( $code, $message ) );
 			}
 		}
 			
@@ -627,7 +668,7 @@ class _Output
 		/* Try to find the breaking hook */
 		if ( $faultyAppOrHookId )
 		{
-			if ( is_numeric( $faultyAppOrHookId ) )
+			if ( \is_numeric( $faultyAppOrHookId ) )
 			{
 				$hookSource = \IPS\Db::i()->select( 'plugin', 'core_hooks', array( 'id=?', $faultyAppOrHookId ) )->first();
 				$plugin = \IPS\Plugin::load( $hookSource );
@@ -639,10 +680,13 @@ class _Output
 				$faulty = \IPS\Member::loggedIn()->language()->addToStack( 'faulty_app', FALSE, array( 'sprintf' => array( $app->_title, \IPS\Http\Url::internal( 'app=core&module=applications&controller=applications', 'admin' ) ) ) );
 			}
 		}
-		
+
+		// Do not cache error pages
+		$allowGuestCache = FALSE;
+
 		/* Send output */
 		\IPS\Output::i()->sidebar['enabled'] = FALSE;
-		$this->sendOutput( \IPS\Theme::i()->getTemplate( 'global', 'core' )->globalTemplate( $title, \IPS\Theme::i()->getTemplate( 'global', 'core' )->error( $title, $message, $code, $extra, $member, $faulty ), array( 'app' => \IPS\Dispatcher::i()->application ? \IPS\Dispatcher::i()->application->directory : NULL, 'module' => \IPS\Dispatcher::i()->module ? \IPS\Dispatcher::i()->module->key : NULL, 'controller' => \IPS\Dispatcher::i()->controller ) ), $httpStatusCode, 'text/html', $httpHeaders, FALSE, FALSE );
+		$this->sendOutput( \IPS\Theme::i()->getTemplate( 'global', 'core' )->globalTemplate( $title, \IPS\Theme::i()->getTemplate( 'global', 'core' )->error( $title, $message, $code, $extra, $member, $faulty ), array( 'app' => \IPS\Dispatcher::i()->application ? \IPS\Dispatcher::i()->application->directory : NULL, 'module' => \IPS\Dispatcher::i()->module ? \IPS\Dispatcher::i()->module->key : NULL, 'controller' => \IPS\Dispatcher::i()->controller ) ), $httpStatusCode, 'text/html', $httpHeaders, $allowGuestCache, FALSE );
 	}
 
 	/**
@@ -684,20 +728,21 @@ class _Output
 	/**
 	 * Send output
 	 *
-	 * @param	string	$output				Content to output
-	 * @param	int		$httpStatusCode		HTTP Status Code
-	 * @param	string	$contentType		HTTP Content-type
-	 * @param	array	$httpHeaders		Additional HTTP Headers
-	 * @param	bool	$cacheThisPage		Can/should this page be cached?
-	 * @param	bool	$pageIsCached		Is the page from a cache? If TRUE, no language parsing will be done
-	 * @param	bool	$parseFileObjects	Should <fileStore.xxx> and <___base_url___> be replaced in the output?
-	 * @param	bool	$parseEmoji			Should Emoji be parsed?
-	 * @return	void
+	 * @param string $output Content to output
+	 * @param int $httpStatusCode HTTP Status Code
+	 * @param string $contentType HTTP Content-type
+	 * @param array $httpHeaders Additional HTTP Headers
+	 * @param bool $cacheThisPage Can/should this page be cached?
+	 * @param bool $pageIsCached Is the page from a cache? If TRUE, no language parsing will be done
+	 * @param bool $parseFileObjects Should `<fileStore.xxx>` and `<___base_url___>` be replaced in the output?
+	 * @param bool $parseEmoji Should Emoji be parsed?
+	 * @return    void
+	 * @throws \Exception
 	 */
 	public function sendOutput( $output='', $httpStatusCode=200, $contentType='text/html', $httpHeaders=array(), $cacheThisPage=TRUE, $pageIsCached=FALSE, $parseFileObjects=TRUE, $parseEmoji=TRUE )
 	{
 		/* Replace language stack keys with actual content */
-		if ( \IPS\Dispatcher::hasInstance() and !in_array( $contentType, array( 'text/javascript', 'text/css', 'application/json' ) ) and $output and !$pageIsCached )
+		if ( \IPS\Dispatcher::hasInstance() and !\in_array( $contentType, array( 'text/javascript', 'text/css', 'application/json' ) ) and $output and !$pageIsCached )
 		{
 			\IPS\Member::loggedIn()->language()->parseOutputForDisplay( $output );
 		}
@@ -707,39 +752,65 @@ class _Output
 		{
 			$this->parseFileObjectUrls( $output );
 		}
-		
+
 		/* Replace emoji */
 		if ( $output and $parseEmoji and \IPS\Dispatcher::hasInstance() and \IPS\Dispatcher::i()->controllerLocation !== 'setup' )
 		{
 			$output = $this->replaceEmojiWithImages( $output );
 		}
 
+		/* Do we want to preload anything? Only send preload headers for full page requests with a text/html response that have output. */
+		if( !$pageIsCached AND !\IPS\IN_DEV AND $output AND !\IPS\Request::i()->isAjax() AND $contentType == 'text/html'  )
+		{
+			if( $urls = $this->getPreloadUrls() AND \count( $urls ) )
+			{
+				/* Send a link header for preloading */
+				//$httpHeaders['Link'] = implode( ', ', $urls );
+			}
+		}
+
 		/* Full page caching for guests */
 		if (
 			\IPS\CACHE_PAGE_TIMEOUT and	$this->pageCaching and							// Page caching is enabled
 			$cacheThisPage and															// Some pages can specify not to be cached (for example, when displaying a cached page, you don't want it recached)
 			!isset( \IPS\Request::i()->cookie['noCache'] ) and							// A noCache cookie might get set to not cache a particular guest (for example, if they have added items to their cart in the store)
-			mb_strtolower( $_SERVER['REQUEST_METHOD'] ) == 'get' and					// Is a HTTP GET request (don't cache output for POSTs)
+			( mb_strtolower( $_SERVER['REQUEST_METHOD'] ) == 'get' OR mb_strtolower( $_SERVER['REQUEST_METHOD'] ) == 'head' ) and					// Is a HTTP GET/HEAD request (don't cache output for POSTs)
 			!isset( \IPS\Request::i()->csrfKey ) and 									// CSRF key isn't present (which would be like a POST request)
-			( $contentType == 'text/html' or $contentType == 'text/xml' ) and			// Output is HTML or XML (don't cache JSON output, etc)
+			( $contentType == 'text/html' or $contentType == 'text/xml' or $contentType == 'application/manifest+json' ) and			// Output is HTML, XML or [PWA] application manifest (don't cache JSON output, etc)
 			\IPS\Dispatcher::hasInstance() and class_exists( 'IPS\Dispatcher', FALSE ) and \IPS\Dispatcher::i()->controllerLocation === 'front' and	// Is a normal, front-end page (necessary to know if user is logged in)
 			!\IPS\Member::loggedIn()->member_id											// User is not logged in
 		) {
 			$theme = isset( \IPS\Request::i()->cookie['theme'] ) ?  \IPS\Request::i()->cookie['theme'] : '';
 
-			\IPS\Data\Cache::i()->storeWithExpire( 'page_' . md5( (int) \IPS\Request::i()->isSecure() . ( !empty( $_SERVER['HTTP_HOST'] ) ? $_SERVER['HTTP_HOST'] : $_SERVER['SERVER_NAME'] ) . '/' . $_SERVER['REQUEST_URI'] ) . '_' . \IPS\Member::loggedIn()->language()->id . '_' . $theme, array(
-				'output'		=> str_replace( \IPS\Session::i()->csrfKey, '{{csrfKey}}', $output ),
-				'code'			=> $httpStatusCode,
-				'contentType'	=> $contentType,
-				'httpHeaders'	=> array_merge( $httpHeaders, array( 'X-IPS-Cached-Response' => \IPS\DateTime::create()->rfc1123() ) ),
-				'lastUpdated'	=> time()
-			), \IPS\DateTime::create()->add( new\DateInterval( 'PT' . \IPS\CACHE_PAGE_TIMEOUT . 'S' ) ), TRUE );
+			\IPS\Output\Cache::i()->set( 'page_' . md5( (string) \IPS\Request::i()->url() ) . '_' . \IPS\Member::loggedIn()->language()->id . '_' . $theme,
+				str_replace( \IPS\Session::i()->csrfKey, '{{csrfKey}}', $output ),
+				array(
+					'code'			=> $httpStatusCode,
+					'contentType'	=> $contentType,
+					'httpHeaders'	=> array_merge( $httpHeaders, array( 'X-IPS-Cached-Response' => \IPS\DateTime::create()->rfc1123() ) ),
+					'lastUpdated'	=> time()
+				), \IPS\DateTime::create()->add( new\DateInterval( 'PT' . \IPS\CACHE_PAGE_TIMEOUT . 'S' ) ), TRUE );
+				
+			/* Add caching headers */
+			if( !isset( $httpHeaders['Cache-Control'] ) )
+			{
+				$httpHeaders += \IPS\Output::getCacheHeaders( time(), \IPS\CACHE_PAGE_TIMEOUT );
+			}
+		}
+
+		/* Include headers set in constructor, intentionally after guest caching. */
+		$httpHeaders = $this->httpHeaders + $httpHeaders;
+
+		/* We will only push resources (http/2) on the first visit, i.e. if the session cookie is not present yet */
+		$location = ( \IPS\Dispatcher::hasInstance() ) ? mb_ucfirst( \IPS\Dispatcher::i()->controllerLocation ) : 'Front';
+
+		if( isset( \IPS\Request::i()->cookie['IPSSession' . $location ] ) AND \IPS\Request::i()->cookie['IPSSession' . $location ] AND isset( $httpHeaders['Link'] ) )
+		{
+			unset( $httpHeaders['Link'] );
 		}
 		
 		/* Query Log (has to be done after parseOutputForDisplay because runs queries and after page caching so the log isn't misleading) */
-		$contentTypeTypes	= explode( '/', $contentType );
-
-		if ( ( \IPS\QUERY_LOG or \IPS\CACHING_LOG ) and in_array( $contentType, array( 'text/html', 'application/json' ) ) )
+		if ( $output and ( \IPS\QUERY_LOG or \IPS\CACHING_LOG or \IPS\REDIS_LOG ) and \in_array( $contentType, array( 'text/html', 'application/json' ) ) and ( \IPS\Dispatcher::hasInstance() and \IPS\Dispatcher::i()->controllerLocation !== 'setup' ) )
 		{
 			/* Close the session and run tasks now so we can see those queries */
 			session_write_close();
@@ -766,7 +837,7 @@ class _Output
 			{
 				$output = str_replace( '<!--ipsQueryLog-->', \IPS\Theme::i()->getTemplate( 'global', 'core', 'front' )->queryLog( $queryLog ), $output );
 			}
-			if ( \IPS\CACHING_LOG )
+			if ( \IPS\CACHING_LOG or \IPS\REDIS_LOG )
 			{
 				$output = str_replace( '<!--ipsCachingLog-->', \IPS\Theme::i()->getTemplate( 'global', 'core', 'front' )->cachingLog( $cachingLog ), $output );
 			}
@@ -784,15 +855,41 @@ class _Output
 		/* Start buffering */
 		ob_start();
 		
-		/* If the browser supports gzip, gzip the content - we do this ourselves so that we can send Content-Length even with mod_gzip */
-		if ( isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) and \strpos( $_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip' ) !== false )
+		/* Generated by a logged in user? */
+		if( \IPS\Dispatcher::hasInstance() )
 		{
-			if ( function_exists( 'gzencode' ) and (bool) ini_get('zlib.output_compression') === false )
+			$this->sendHeader( "X-IPS-LoggedIn: " . ( ( \IPS\Member::loggedIn()->member_id ) ? 1 : 0 ) );
+		}
+		
+		$vary = array( 'cookie' );
+		
+		/* Can we compress the content? */
+		if ( $output and isset( $_SERVER['HTTP_ACCEPT_ENCODING'] ) )
+		{
+			/* If php zlib.output_compression is on, don't do anything since PHP will */
+			if( (bool) ini_get('zlib.output_compression') === false )
 			{
-				$output = gzencode( $output ); // mod_gzip will encode pages, but we want to encode ourselves so that Content-Length is correct
-				$this->sendHeader("Content-Encoding: gzip"); // Tells the server we've alredy encoded so it doesn't need to
+				/* Try brotli first - support will be rare, but preferred if it is available */
+				if ( \strpos( $_SERVER['HTTP_ACCEPT_ENCODING'], 'br' ) !== false and \function_exists( 'brotli_compress' ) )
+				{
+					$output = brotli_compress( $output );
+					$this->sendHeader( "Content-Encoding: br" ); // Tells the server we've alredy encoded so it doesn't need to
+					$vary[] = "Accept-Encoding"; // Tells proxy caches that the response varies depending upon encoding
+				}
+				/* If the browser supports gzip, gzip the content - we do this ourselves so that we can send Content-Length even with mod_gzip */
+				elseif ( \strpos( $_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip' ) !== false and \function_exists( 'gzencode' ) )
+				{
+					$output = gzencode( $output ); // mod_gzip will encode pages, but we want to encode ourselves so that Content-Length is correct
+					$this->sendHeader( "Content-Encoding: gzip" ); // Tells the server we've alredy encoded so it doesn't need to
+					$vary[] = "Accept-Encoding"; // Tells proxy caches that the response varies depending upon encoding
+				}
 			}
 		}
+		
+		if ( \count( $vary ) )
+		{
+			$this->sendHeader( "Vary: " . implode( ", ", $vary ) );
+		}
 
 		/* Output */
 		print $output;
@@ -810,17 +907,6 @@ class _Output
 			$size = ob_get_length();
 			$this->sendHeader( "Content-Length: {$size}" ); // Makes sure the connection closes after sending output so that tasks etc aren't holding it open
 		}
-
-		/* Do we want to preload anything? */
-		foreach( $this->linkTags as $tag )
-		{
-			/* We are only doing this for rel=preload, and the 'as' parameter is not optional */
-			if( is_array( $tag ) AND isset( $tag['rel'] ) AND $tag['rel'] == 'preload' AND isset( $tag['as'] ) AND $tag['as'] )
-			{
-				$as = ( isset( $tag['as'] ) ) ? "; as=" . $tag['as'] : '';
-				$this->sendHeader( "Link: " . $tag['href'] . '; rel=preload' . $as );
-			}
-		}
 		
 		/* Rest of our HTTP headers */
 		foreach ( $httpHeaders as $key => $header )
@@ -839,21 +925,98 @@ class _Output
 		@ob_end_flush();
 		@flush();
 
+		/* Log headers if we are set to do so */
+		if( \IPS\DEV_LOG_HEADERS === TRUE )
+		{
+			$this->_logHeadersSent();
+		}
+
 		/* If using PHP-FPM, close the request so that __destruct tasks are run after data is flushed to the browser
 			@see http://www.php.net/manual/en/function.fastcgi-finish-request.php */
-		if( function_exists( 'fastcgi_finish_request' ) )
+		if( \function_exists( 'fastcgi_finish_request' ) )
 		{
 			fastcgi_finish_request();
 		}
 
 		exit;
 	}
+
+	/**
+	 * Logs the headers that have been sent, if we are able to do so
+	 *
+	 * @return void
+	 */
+	protected function _logHeadersSent()
+	{
+		$headers = NULL;
+
+		if( \function_exists('headers_list') )
+		{
+			$headers = headers_list();
+		}
+		elseif( \function_exists('apache_response_headers') )
+		{
+			$headers = apache_response_headers();
+		}
+		elseif( \function_exists('xdebug_get_headers') )
+		{
+			$headers = xdebug_get_headers();
+		}
+
+		if( $headers !== NULL )
+		{
+			\IPS\Log::log( $headers, 'httpHeaders' );
+		}
+	}
+
+	/**
+	 * Fetch the URLs to preload (via Link: HTTP header)
+	 *
+	 * @return array
+	 */
+	public function getPreloadUrls()
+	{
+		/* http/2 push resources */
+		$preload = array();
+
+		foreach( $this->linkTags as $tag )
+		{
+			/* We are only doing this for rel=preload, and the 'as' parameter is not optional. Preloading fonts currently does not work as expected in Chrome, resulting in the font file downloading twice, so we will skip fonts. */
+			if( \is_array( $tag ) AND isset( $tag['rel'] ) AND $tag['rel'] == 'preload' AND isset( $tag['as'] ) AND $tag['as'] AND $tag['as'] != 'font' )
+			{
+				$preload[] = $tag['href'] . '; rel=preload; as=' .  $tag['as'];
+			}
+		}
+
+		$cssFilesToCheck = ( \IPS\Dispatcher::hasInstance() AND \IPS\Dispatcher::i()->controllerLocation == 'setup' ) ? \IPS\Output::i()->cssFiles : array_merge( \IPS\Output::i()->cssFiles, \IPS\Theme::i()->css( 'custom.css', 'core', 'front' ) );
+
+		foreach( array_unique( $cssFilesToCheck, SORT_STRING ) as $css )
+		{
+			$url = \IPS\Http\Url::external( $css )->setQueryString( 'v', \IPS\CACHEBUST_KEY );
+			$preload[] = (string) $url . '; rel=preload; as=style';
+		}
+		
+		foreach( array_unique( array_filter( array_merge( \IPS\Output::i()->jsFiles, \IPS\Output::i()->jsFilesAsync ) ), SORT_STRING ) as $js )
+		{
+			$url = \IPS\Http\Url::external( $js );
+
+			if( $url->data['host'] == parse_url( \IPS\Settings::i()->base_url, PHP_URL_HOST ) )
+			{
+				$url = $url->setQueryString( 'v', \IPS\CACHEBUST_KEY );
+			}
+
+			$preload[] = (string) $url . '; rel=preload; as=script';
+		}
+
+		/* Only include the first 30 entries if there are a lot */
+		return \array_slice( $preload, 0, 30 );
+	}
 	
 	/**
 	 * Send JSON output
 	 *
-	 * @param	string	$data	Data to be JSON-encoded
-	 * @param	int		$httpStatusCode		HTTP Status Code
+	 * @param	string|array	$data	Data to be JSON-encoded
+	 * @param	int				$httpStatusCode		HTTP Status Code
 	 * @return	void
 	 */
 	public function json( $data, $httpStatusCode=200 )
@@ -900,12 +1063,12 @@ class _Output
 			{
 				$message = \IPS\Member::loggedIn()->language()->addToStack( $message );
 				\IPS\Member::loggedIn()->language()->parseOutputForDisplay( $message );
-				$_SESSION['inlineMessage'] = $message;
+				static::setInlineMessage( $message );
 				session_write_close();
 			}
 			elseif( $this->inlineMessage )
 			{
-				$_SESSION['inlineMessage'] = $this->inlineMessage;
+				static::setInlineMessage( $this->inlineMessage );
 				session_write_close();
 			}
 
@@ -969,7 +1132,7 @@ class _Output
 	 */
 	public function replaceEmojiWithImages( $output )
 	{
-		if ( \IPS\Settings::i()->emoji_style == 'twemoji' or \IPS\Settings::i()->emoji_style == 'emojione' )
+		if ( \IPS\Settings::i()->emoji_style == 'twemoji' )
 		{
 			return preg_replace_callback( '/<span class="ipsEmoji">(.+?)<\/span>/', function( $matches ) {
 				$hex = bin2hex( mb_convert_encoding( $matches[1], 'UTF-32', 'UTF-8' ) );
@@ -1004,26 +1167,19 @@ class _Output
 				    
 			        $chunks[ $i ] = $res;
 			    }
-			    
-			    if ( \IPS\Settings::i()->emoji_style == 'twemoji' )
-			    {	
-					$image = implode( '-', $chunks );
-					
-					if ( \strstr( $image, '200d' ) === FALSE or $image === '1f441-fe0f-200d-1f5e8-fe0f' )
-					{
-						$image = str_replace( '-fe0f', '', $image );
-					}
-					if ( in_array( $image, array( '0031-20e3', '0030-20e3', '0032-20e3', '0034-20e3', '0035-20e3', '0036-20e3', '0037-20e3', '0038-20e3', '0033-20e3', '0039-20e3', '0023-20e3', '002a-20e3', '00a9', '00ae' ) ) )
-					{
-						$image = str_replace( '00', '', $image );
-					}
-				    
-					return '<img src="https://twemoji.maxcdn.com/2/72x72/'  . $image . '.png" class="ipsEmoji" alt="' . $matches[1] . '">';
-				}
-				else
+
+				$image = implode( '-', $chunks );
+				
+				if ( \strstr( $image, '200d' ) === FALSE or $image === '1f441-fe0f-200d-1f5e8-fe0f' )
 				{
-					return '<img src="https://cdn.jsdelivr.net/emojione/assets/3.1/png/64/'  . str_replace( array( '-200d', '-fe0f' ), '', implode( '-', $chunks ) ) . '.png" class="ipsEmoji" alt="' . $matches[1] . '">';
+					$image = str_replace( '-fe0f', '', $image );
 				}
+				if ( \in_array( $image, array( '0031-20e3', '0030-20e3', '0032-20e3', '0034-20e3', '0035-20e3', '0036-20e3', '0037-20e3', '0038-20e3', '0033-20e3', '0039-20e3', '0023-20e3', '002a-20e3', '00a9', '00ae' ) ) )
+				{
+					$image = str_replace( '00', '', $image );
+				}
+			    
+				return '<img src="https://twemoji.maxcdn.com/2/72x72/'  . $image . '.png" class="ipsEmoji" alt="' . $matches[1] . '">';
 			}, $output );
 		}
 		return $output;
@@ -1104,7 +1260,7 @@ class _Output
 	{
 		$javascriptObjects = ( isset( \IPS\Data\Store::i()->javascript_map ) ) ? \IPS\Data\Store::i()->javascript_map : array();
 
-		if ( ! is_array( $javascriptObjects ) OR ! count( $javascriptObjects ) OR ! isset( $javascriptObjects[ $app ] ) )
+		if ( ! \is_array( $javascriptObjects ) OR ! \count( $javascriptObjects ) OR ! isset( $javascriptObjects[ $app ] ) )
 		{
 			/* Map is broken or missing, recompile all JS */
 			\IPS\Output\Javascript::compile( $app );
@@ -1132,6 +1288,8 @@ class _Output
 		{
 			$this->title .= ' - ' . \IPS\Settings::i()->board_name;
 		}
+
+		$this->defaultPageTitle	= $this->title;
 		
 		/* Add Admin-specified ones */
 		if( !$this->metaTagsUrl )
@@ -1148,8 +1306,11 @@ class _Output
 				\IPS\Data\Store::i()->metaTags = $rows;
 			}
 						
-			if( is_array( $rows ) )
+			if( \is_array( $rows ) )
 			{
+				/* We duplicate these so we can know what is generated automatically for the live meta tag editor */
+				$this->autoMetaTags = $this->metaTags;
+
 				foreach ( $rows as $row )
 				{
 					if( \strpos( $row['meta_url'], '*' ) !== FALSE )
@@ -1158,11 +1319,20 @@ class _Output
 						{
 							$_tags	= json_decode( $row['meta_tags'], TRUE );
 		
-							if( is_array( $_tags ) )
+							if( \is_array( $_tags ) )
 							{
 								foreach( $_tags as $_tagName => $_tagContent )
 								{
-									$this->metaTags[ $_tagName ]	= $_tagContent;
+									if( $_tagContent === NULL )
+									{
+										unset( $this->metaTags[ $_tagName ] );
+									}
+									else
+									{
+										$this->metaTags[ $_tagName ]		= $_tagContent;
+									}
+
+									$this->customMetaTags[ $_tagName ]	= $_tagContent;
 								}
 							}
 		
@@ -1176,15 +1346,25 @@ class _Output
 					}
 					else
 					{
-						if( trim( $row['meta_url'], '/' ) == trim( $this->metaTagsUrl, '/' ) )
+						$rootPath = \IPS\Http\Url::external( \IPS\Settings::i()->base_url )->data['path'];
+						if( trim( $row['meta_url'], '/' ) == trim( $this->metaTagsUrl, '/' ) and ( ( $row['meta_url'] == '/' and \IPS\Request::i()->url()->data['path'] == $rootPath ) or $row['meta_url'] !== '/' ) )
 						{
 							$_tags	= json_decode( $row['meta_tags'], TRUE );
 							
-							if ( is_array( $_tags ) )
+							if ( \is_array( $_tags ) )
 							{
 								foreach( $_tags as $_tagName => $_tagContent )
 								{
-									$this->metaTags[ $_tagName ]	= $_tagContent;
+									if( $_tagContent === NULL )
+									{
+										unset( $this->metaTags[ $_tagName ] );
+									}
+									else
+									{
+										$this->metaTags[ $_tagName ]		= $_tagContent;
+									}
+
+									$this->customMetaTags[ $_tagName ]	= $_tagContent;
 								}
 							}
 							
@@ -1204,7 +1384,7 @@ class _Output
 
 		foreach( $this->metaTags as $name => $value )
 		{
-			if ( ! is_array( $value ) )
+			if ( ! \is_array( $value ) )
 			{
 				$value = array( $value );
 			}
@@ -1232,7 +1412,10 @@ class _Output
 		$jsonLd = array(
 			'website'		=> array(
 				'@context'	=> "http://www.schema.org",
+				'publisher' => \IPS\Settings::i()->base_url . '#organization',
 				'@type'		=> "WebSite",
+				'@id' 		=> \IPS\Settings::i()->base_url . '#website',
+	            'mainEntityOfPage' => \IPS\Settings::i()->base_url,
 				'name'		=> \IPS\Settings::i()->board_name,
 				'url'		=> \IPS\Settings::i()->base_url,
 				'potentialAction'	=> array(
@@ -1245,17 +1428,23 @@ class _Output
 			'organization'	=> array(
 				'@context'	=> "http://www.schema.org",
 				'@type'		=> "Organization",
+				'@id' 		=> \IPS\Settings::i()->base_url . '#organization',
+	            'mainEntityOfPage' => \IPS\Settings::i()->base_url,
 				'name'		=> \IPS\Settings::i()->board_name,
 				'url'		=> \IPS\Settings::i()->base_url,
 			)
 		);
 
-		if( \IPS\Theme::i()->logo_front )
+		if( $logo = \IPS\Theme::i()->logo_front )
 		{
-			$jsonLd['organization']['logo'] = (string) \IPS\Theme::i()->logo_front;
+			$jsonLd['organization']['logo'] = array(
+				'@type' => 'ImageObject',
+	            '@id'   => \IPS\Settings::i()->base_url . '#logo',
+	            'url'   => (string) $logo
+			);
 		}
 
-		if( \IPS\Settings::i()->site_social_profiles AND $links = json_decode( \IPS\Settings::i()->site_social_profiles, TRUE ) AND count( $links ) )
+		if( \IPS\Settings::i()->site_social_profiles AND $links = json_decode( \IPS\Settings::i()->site_social_profiles, TRUE ) AND \count( $links ) )
 		{
 			if( !isset( $jsonLd['organization']['sameAs'] ) )
 			{
@@ -1270,14 +1459,17 @@ class _Output
 
 		if( \IPS\Settings::i()->site_address AND $address = \IPS\GeoLocation::buildFromJson( \IPS\Settings::i()->site_address ) )
 		{
-			$jsonLd['organization']['address'] = array(
-				'@type'				=> 'PostalAddress',
-				'streetAddress'		=> implode( ', ', $address->addressLines ),
-				'addressLocality'	=> $address->city,
-				'addressRegion'		=> $address->region,
-				'postalCode'		=> $address->postalCode,
-				'addressCountry'	=> $address->country,
-			);
+			if ( ! empty( $address->country ) )
+			{
+				$jsonLd['organization']['address'] = array(
+					'@type'				=> 'PostalAddress',
+					'streetAddress'		=> implode( ', ', $address->addressLines ),
+					'addressLocality'	=> $address->city,
+					'addressRegion'		=> $address->region,
+					'postalCode'		=> $address->postalCode,
+					'addressCountry'	=> $address->country,
+				);
+			}
 		}
 
 		foreach( \IPS\Lang::getEnabledLanguages() as $language )
@@ -1290,21 +1482,17 @@ class _Output
 		}
 
 		/* Add breadcrumbs */
-		if( count( $this->breadcrumb ) )
+		if( \count( $this->breadcrumb ) )
 		{
-			$jsonLd['breadcrumbs'] = array(
-				'@context'	=> "http://schema.org",
-				'@type'		=> "BreadcrumbList",
-				'itemListElement'	=> array(),
-			);
 
 			$position	= 1;
+			$elements	= [];
 
 			foreach( $this->breadcrumb as $breadcrumb )
 			{
 				if( $breadcrumb[0] )
 				{
-					$jsonLd['breadcrumbs']['itemListElement'][] = array(
+					$elements[] = array(
 						'@type'		=> "ListItem",
 						'position'	=> $position,
 						'item'		=> array(
@@ -1316,6 +1504,15 @@ class _Output
 					$position++;
 				}
 			}
+
+			if( \count( $elements ) )
+			{
+				$jsonLd['breadcrumbs'] = array(
+					'@context'	=> "http://schema.org",
+					'@type'		=> "BreadcrumbList",
+					'itemListElement'	=> $elements,
+				);
+			}
 		}
 
 		if( \IPS\Member::loggedIn()->canUseContactUs() )
@@ -1329,11 +1526,12 @@ class _Output
 		
 		$this->jsonLd	= array_merge( $this->jsonLd, $jsonLd );
 	}
-	
+
 	/**
 	 * License Warning
 	 *
-	 * @return	string|NULL		"none" = no license key. "expired" = license key expired. NULL = no error
+	 * @return		string|NULL		"none" = no license key. "expired" = license key expired. NULL = no error
+	 * @deprecated	to be removed in 4.5
 	 */
 	public function licenseKeyWarning()
 	{
@@ -1361,6 +1559,7 @@ class _Output
 	 * Days remaining before license expires
 	 *
 	 * @return		int|NULL	NULL or the number of days remaining
+	 * @deprecated	to be removed in 4.5
 	 */
 	public function licenseKeyDaysRemaining()
 	{
@@ -1381,7 +1580,7 @@ class _Output
 
 		return $daysLeft;
 	}
-
+	
 	/**
 	 * @brief	Global search menu options
 	 */
@@ -1443,4 +1642,41 @@ class _Output
 
 		return $output;
 	}
+	
+	/**
+	 * Get any inline message
+	 *
+	 * @return	string
+	 */
+	protected static function getInlineMessage()
+	{
+		if ( ( \IPS\Dispatcher::hasInstance() and \IPS\Dispatcher::i()->controllerLocation == 'front' ) and ( \IPS\Session\Front::loggedIn() or isset( \IPS\Request::i()->cookie['noCache'] ) ) ) # Don't attempt to initiate a full member object here
+		{
+			return ( ( isset( $_SESSION['inlineMessage'] ) and ! empty( $_SESSION['inlineMessage'] ) ) ? $_SESSION['inlineMessage'] : NULL );
+		}
+		else if ( isset( \IPS\Request::i()->cookie['inlineMessage'] ) )
+		{
+			return \IPS\Request::i()->cookie['inlineMessage'];
+		}
+		
+		return NULL; 
+	}
+	
+	/**
+	 * Set an inline message
+	 *
+	 * @param	string	$message	The message
+	 * @return	void
+	 */
+	protected static function setInlineMessage( $message=NULL )
+	{
+		if ( ( \IPS\Dispatcher::hasInstance() and \IPS\Dispatcher::i()->controllerLocation == 'front' ) and ( \IPS\Session\Front::loggedIn() or isset( \IPS\Request::i()->cookie['noCache'] ) ) ) # Don't attempt to initiate a full member object here
+		{
+			$_SESSION['inlineMessage'] = $message;
+		}
+		else
+		{
+			\IPS\Request::i()->setCookie( 'inlineMessage', $message );
+		}
+	}
 }