Add themed error pages

- Module init, post and rawContent-triggered HTTPException generate the classic bare HTTP status page
- Module content-triggered HTTPException generate themed error pages
- Trim System::httpExit to the bare minimum

src/App.php

@@ -14,7 +14,7 @@ use Friendica\Core\Hook;
 use Friendica\Core\Theme;
 use Friendica\Database\DBA;
 use Friendica\Model\Profile;
-use Friendica\Network\HTTPException\InternalServerErrorException;
+use Friendica\Network\HTTPException;
 use Friendica\Util\BaseURL;
 use Friendica\Util\Config\ConfigFileLoader;
 use Friendica\Util\HTTPSignature;
@@ -572,7 +572,7 @@ class App
 	 * @param string $origURL
 	 *
 	 * @return string The cleaned url
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function removeBaseURL($origURL)
 	{
@@ -593,7 +593,7 @@ class App
 	 * Returns the current UserAgent as a String
 	 *
 	 * @return string the UserAgent as a String
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function getUserAgent()
 	{
@@ -723,7 +723,7 @@ class App
 	 * @brief Checks if the minimal memory is reached
 	 *
 	 * @return bool Is the memory limit reached?
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function isMinMemoryReached()
 	{
@@ -768,7 +768,7 @@ class App
 	 * @brief Checks if the maximum load is reached
 	 *
 	 * @return bool Is the load reached?
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function isMaxLoadReached()
 	{
@@ -801,7 +801,7 @@ class App
 	 *
 	 * @param string $command The command to execute
 	 * @param array  $args    Arguments to pass to the command ( [ 'key' => value, 'key2' => value2, ... ]
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function proc_run($command, $args)
 	{
@@ -842,7 +842,7 @@ class App
 	 * Generates the site's default sender email address
 	 *
 	 * @return string
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function getSenderEmailAddress()
 	{
@@ -863,7 +863,7 @@ class App
 	 * Returns the current theme name.
 	 *
 	 * @return string the name of the current theme
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function getCurrentTheme()
 	{
@@ -944,7 +944,7 @@ class App
 	 * Provide a sane default if nothing is chosen or the specified theme does not exist.
 	 *
 	 * @return string
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function getCurrentThemeStylesheetPath()
 	{
@@ -1010,7 +1010,10 @@ class App
 	{
 		// Missing DB connection: ERROR
 		if ($this->getMode()->has(App\Mode::LOCALCONFIGPRESENT) && !$this->getMode()->has(App\Mode::DBAVAILABLE)) {
-			Core\System::httpExit(500, ['title' => 'Error 500 - Internal Server Error', 'description' => 'Apologies but the website is unavailable at the moment.']);
+			echo Module\Special\HTTPException::rawContent(
+				new HTTPException\InternalServerErrorException('Apologies but the website is unavailable at the moment.')
+			);
+			exit;
 		}
 
 		// Max Load Average reached: ERROR
@@ -1018,11 +1021,17 @@ class App
 			header('Retry-After: 120');
 			header('Refresh: 120; url=' . $this->getBaseURL() . "/" . $this->query_string);
 
-			Core\System::httpExit(503, ['title' => 'Error 503 - Service Temporarily Unavailable', 'description' => 'Core\System is currently overloaded. Please try again later.']);
+			echo Module\Special\HTTPException::rawContent(
+				new HTTPException\ServiceUnavaiableException('The node is currently overloaded. Please try again later.')
+			);
+			exit;
 		}
 
 		if (strstr($this->query_string, '.well-known/host-meta') && ($this->query_string != '.well-known/host-meta')) {
-			Core\System::httpExit(404);
+			echo Module\Special\HTTPException::rawContent(
+				new HTTPException\NotFoundException()
+			);
+			exit;
 		}
 
 		if (!$this->getMode()->isInstall()) {
@@ -1073,7 +1082,10 @@ class App
 					// Someone came with an invalid parameter, maybe as a DDoS attempt
 					// We simply stop processing here
 					Core\Logger::log("Invalid ZRL parameter " . $_GET['zrl'], Core\Logger::DEBUG);
-					Core\System::httpExit(403, ['title' => '403 Forbidden']);
+					echo Module\Special\HTTPException::rawContent(
+						new HTTPException\ForbiddenException()
+					);
+					exit;
 				}
 			}
 		}
@@ -1126,7 +1138,6 @@ class App
 			'title' => ''
 		];
 
-		if (strlen($this->module)) {
 		// Compatibility with the Android Diaspora client
 		if ($this->module == 'stream') {
 			$this->internalRedirect('network?f=&order=post');
@@ -1190,7 +1201,7 @@ class App
 				include_once "addon/{$this->module}/{$this->module}.php";
 				if (function_exists($this->module . '_module')) {
 					LegacyModule::setModuleFile("addon/{$this->module}/{$this->module}.php");
-						$this->module_class = 'Friendica\\LegacyModule';
+					$this->module_class = LegacyModule::class;
 				}
 			}
 		}
@@ -1205,7 +1216,7 @@ class App
 		 */
 		if (!$this->module_class && file_exists("mod/{$this->module}.php")) {
 			LegacyModule::setModuleFile("mod/{$this->module}.php");
-				$this->module_class = 'Friendica\\LegacyModule';
+			$this->module_class = LegacyModule::class;
 		}
 
 		/* The URL provided does not resolve to a valid module.
@@ -1230,19 +1241,12 @@ class App
 
 			Core\Logger::log('index.php: page not found: ' . $_SERVER['REQUEST_URI'] . ' ADDRESS: ' . $_SERVER['REMOTE_ADDR'] . ' QUERY: ' . $_SERVER['QUERY_STRING'], Core\Logger::DEBUG);
 
-				header($_SERVER["SERVER_PROTOCOL"] . ' 404 ' . Core\L10n::t('Not Found'));
+			$this->module_class = Module\PageNotFound::class;
-				$tpl = Core\Renderer::getMarkupTemplate("404.tpl");
-				$this->page['content'] = Core\Renderer::replaceMacros($tpl, [
-					'$message' =>  Core\L10n::t('Page not found.')
-				]);
 		}
-		}
-
-		$content = '';
 
 		// Initialize module that can set the current theme in the init() method, either directly or via App->profile_uid
-		if ($this->module_class) {
 		$this->page['page_title'] = $this->module;
+		try {
 			$placeholder = '';
 
 			Core\Hook::callAll($this->module . '_mod_init', $placeholder);
@@ -1252,7 +1256,6 @@ class App
 			// "rawContent" is especially meant for technical endpoints.
 			// This endpoint doesn't need any theme initialization or other comparable stuff.
 			call_user_func([$this->module_class, 'rawContent']);
-		}
 
 			// Load current theme info after module has been initialized as theme could have been set in module
 			$theme_info_file = 'view/theme/' . $this->getCurrentTheme() . '/theme.php';
@@ -1265,7 +1268,6 @@ class App
 				$func($this);
 			}
 
-		if ($this->module_class) {
 			if ($_SERVER['REQUEST_METHOD'] === 'POST') {
 				Core\Hook::callAll($this->module . '_mod_post', $_POST);
 				call_user_func([$this->module_class, 'post']);
@@ -1273,13 +1275,22 @@ class App
 
 			Core\Hook::callAll($this->module . '_mod_afterpost', $placeholder);
 			call_user_func([$this->module_class, 'afterpost']);
+		} catch(HTTPException $e) {
+			echo Module\Special\HTTPException::rawContent($e);
+			exit;
+		}
 
+		$content = '';
+
+		try {
 			$arr = ['content' => $content];
 			Core\Hook::callAll($this->module . '_mod_content', $arr);
 			$content = $arr['content'];
 			$arr = ['content' => call_user_func([$this->module_class, 'content'])];
 			Core\Hook::callAll($this->module . '_mod_aftercontent', $arr);
 			$content .= $arr['content'];
+		} catch(HTTPException $e) {
+			$content = Module\Special\HTTPException::content($e);
 		}
 
 		// initialise content region
@@ -1303,13 +1314,6 @@ class App
 		 */
 		$this->initFooter();
 
-		/* now that we've been through the module content, see if the page reported
-		 * a permission problem and if so, a 403 response would seem to be in order.
-		 */
-		if (stristr(implode("", $_SESSION['sysmsg']), Core\L10n::t('Permission denied'))) {
-			header($_SERVER["SERVER_PROTOCOL"] . ' 403 ' . Core\L10n::t('Permission denied.'));
-		}
-
 		if (!$this->isAjax()) {
 			Core\Hook::callAll('page_end', $this->page['content']);
 		}
@@ -1401,12 +1405,12 @@ class App
 	 * @param string $toUrl The destination URL (Default is empty, which is the default page of the Friendica node)
 	 * @param bool $ssl if true, base URL will try to get called with https:// (works just for relative paths)
 	 *
-	 * @throws InternalServerErrorException In Case the given URL is not relative to the Friendica node
+	 * @throws HTTPException\InternalServerErrorException In Case the given URL is not relative to the Friendica node
 	 */
 	public function internalRedirect($toUrl = '', $ssl = false)
 	{
 		if (!empty(parse_url($toUrl, PHP_URL_SCHEME))) {
-			throw new InternalServerErrorException("'$toUrl is not a relative path, please use System::externalRedirectTo");
+			throw new HTTPException\InternalServerErrorException("'$toUrl is not a relative path, please use System::externalRedirectTo");
 		}
 
 		$redirectTo = $this->getBaseURL($ssl) . '/' . ltrim($toUrl, '/');
@@ -1418,7 +1422,7 @@ class App
 	 * Should only be used if it isn't clear if the URL is either internal or external
 	 *
 	 * @param string $toUrl The target URL
-	 * @throws InternalServerErrorException
+	 * @throws HTTPException\InternalServerErrorException
 	 */
 	public function redirect($toUrl)
 	{

src/Core/System.php

@@ -121,57 +121,16 @@ class System extends BaseObject
 	 * @brief Send HTTP status header and exit.
 	 *
 	 * @param integer $val     HTTP status result value
-	 * @param array   $description optional message
+	 * @param string  $message Error message. Optional.
-	 *                             'title' => header title
+	 * @param string  $content Response body. Optional.
-	 *                             'description' => optional message
+	 * @throws \Exception
-	 * @throws InternalServerErrorException
 	 */
-	public static function httpExit($val, $description = [])
+	public static function httpExit($val, $message = '', $content = '')
 	{
-		$err = '';
-		if ($val >= 400) {
-			if (!empty($description['title'])) {
-				$err = $description['title'];
-			} else {
-				$title = [
-					'400' => L10n::t('Error 400 - Bad Request'),
-					'401' => L10n::t('Error 401 - Unauthorized'),
-					'403' => L10n::t('Error 403 - Forbidden'),
-					'404' => L10n::t('Error 404 - Not Found'),
-					'500' => L10n::t('Error 500 - Internal Server Error'),
-					'503' => L10n::t('Error 503 - Service Unavailable'),
-					];
-				$err = defaults($title, $val, 'Error ' . $val);
-				$description['title'] = $err;
-			}
-			if (empty($description['description'])) {
-				// Explanations are taken from https://en.wikipedia.org/wiki/List_of_HTTP_status_codes
-				$explanation = [
-					'400' => L10n::t('The server cannot or will not process the request due to an apparent client error.'),
-					'401' => L10n::t('Authentication is required and has failed or has not yet been provided.'),
-					'403' => L10n::t('The request was valid, but the server is refusing action. The user might not have the necessary permissions for a resource, or may need an account.'),
-					'404' => L10n::t('The requested resource could not be found but may be available in the future.'),
-					'500' => L10n::t('An unexpected condition was encountered and no more specific message is suitable.'),
-					'503' => L10n::t('The server is currently unavailable (because it is overloaded or down for maintenance). Please try again later.'),
-					];
-				if (!empty($explanation[$val])) {
-					$description['description'] = $explanation[$val];
-				}
-			}
-		}
-
-		if ($val >= 200 && $val < 300) {
-			$err = 'OK';
-		}
-
 		Logger::log('http_status_exit ' . $val);
-		header($_SERVER["SERVER_PROTOCOL"] . ' ' . $val . ' ' . $err);
+		header($_SERVER["SERVER_PROTOCOL"] . ' ' . $val . ' ' . $message);
 
-		if (isset($description["title"])) {
+		echo $content;
-			$tpl = Renderer::getMarkupTemplate('http_status.tpl');
-			echo Renderer::replaceMacros($tpl, ['$title' => $description["title"],
-				'$description' => defaults($description, 'description', '')]);
-		}
 
 		exit();
 	}

src/Module/PageNotFound.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Friendica\Module;
+
+use Friendica\BaseModule;
+use Friendica\Core\L10n;
+use Friendica\Network\HTTPException;
+
+class PageNotFound extends BaseModule
+{
+	public static function content()
+	{
+		throw new HTTPException\NotFoundException(L10n::t('Page not found.'));
+	}
+}

src/Module/Special/HTTPException.php

@@ -0,0 +1,91 @@
+<?php
+
+
+namespace Friendica\Module\Special;
+
+use Friendica\Core\L10n;
+use Friendica\Core\Logger;
+use Friendica\Core\Renderer;
+use Friendica\Core\System;
+
+/**
+ * This special module displays HTTPException when they are thrown in modules.
+ *
+ * @package Friendica\Module\Special
+ */
+class HTTPException
+{
+	/**
+	 * Generates the necessary template variables from the caught HTTPException.
+	 *
+	 * Fills in the blanks if title or descriptions aren't provided by the exception.
+	 *
+	 * @param \Friendica\Network\HTTPException $e
+	 * @return array ['$title' => ..., '$description' => ...]
+	 */
+	private static function getVars(\Friendica\Network\HTTPException $e)
+	{
+		$message = $e->getMessage();
+
+		$titles = [
+			200 => 'OK',
+			400 => L10n::t('Bad Request'),
+			401 => L10n::t('Unauthorized'),
+			403 => L10n::t('Forbidden'),
+			404 => L10n::t('Not Found'),
+			500 => L10n::t('Internal Server Error'),
+			503 => L10n::t('Service Unavailable'),
+		];
+		$title = defaults($titles, $e->getCode(), 'Error ' . $e->getCode());
+
+		if (empty($message)) {
+			// Explanations are taken from https://en.wikipedia.org/wiki/List_of_HTTP_status_codes
+			$explanation = [
+				400 => L10n::t('The server cannot or will not process the request due to an apparent client error.'),
+				401 => L10n::t('Authentication is required and has failed or has not yet been provided.'),
+				403 => L10n::t('The request was valid, but the server is refusing action. The user might not have the necessary permissions for a resource, or may need an account.'),
+				404 => L10n::t('The requested resource could not be found but may be available in the future.'),
+				500 => L10n::t('An unexpected condition was encountered and no more specific message is suitable.'),
+				503 => L10n::t('The server is currently unavailable (because it is overloaded or down for maintenance). Please try again later.'),
+			];
+
+			$message = defaults($explanation, $e->getCode(), '');
+		}
+
+		return ['$title' => $title, '$description' => $message];
+	}
+
+	/**
+	 * Displays a bare message page with no theming at all.
+	 *
+	 * @param \Friendica\Network\HTTPException $e
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 */
+	public static function rawContent(\Friendica\Network\HTTPException $e)
+	{
+		$content = '';
+
+		if ($e->getCode() >= 400) {
+			$tpl = Renderer::getMarkupTemplate('http_status.tpl');
+			$content = Renderer::replaceMacros($tpl, self::getVars($e));
+		}
+
+		System::httpExit($e->getCode(), $e->httpdesc, $content);
+	}
+
+	/**
+	 * Returns a content string that can be integrated in the current theme.
+	 *
+	 * @param \Friendica\Network\HTTPException $e
+	 * @return string
+	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+	 */
+	public static function content(\Friendica\Network\HTTPException $e)
+	{
+		header($_SERVER["SERVER_PROTOCOL"] . ' ' . $e->getCode() . ' ' . $e->httpdesc);
+
+		$tpl = Renderer::getMarkupTemplate('exception.tpl');
+
+		return Renderer::replaceMacros($tpl, self::getVars($e));
+	}
+}

view/templates/exception.tpl

@@ -0,0 +1,4 @@
+<div id="exception" class="generic-page-wrapper">
+    <h1>{{$title}}</h1>
+    <p>{{$message}}</p>
+</div>