Add an exception handler, a small exception hierarchy and middleware support

qa-include/app/page.php

@@ -23,8 +23,9 @@ use Q2A\Controllers\User\UserMessages;
 use Q2A\Controllers\User\UserPosts;
 use Q2A\Controllers\User\UserProfile;
 use Q2A\Controllers\User\UsersList;
-use Q2A\Http\Route;
-use Q2A\Http\Router;
+use Q2A\Exceptions\ExceptionHandler;
+use Q2A\Http\Routing\Route;
+use Q2A\Http\Routing\Router;
 
 if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
 	header('Location: ../../');
@@ -193,8 +194,11 @@ function qa_get_request_content()
 		qa_set_template($route->getId());
 		$controllerClass = $route->getController();
 		$ctrl = new $controllerClass();
-		$qa_content = $ctrl->executeAction($route->getAction(), $route->getParameters());
-
+		try {
+			$qa_content = $ctrl->executeAction($route->getAction(), $route->getParameters());
+		} catch (Exception $e) {
+			$qa_content = (new ExceptionHandler())->handle($e);
+		}
 	} elseif (isset($routing[$requestlower])) {
 		qa_set_template($firstlower);
 		$qa_content = require QA_INCLUDE_DIR . $routing[$requestlower];

qa-src/Auth/InternalUsersOnlyException.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Auth;
+
+use Q2A\Exceptions\FatalErrorException;
+
+class InternalUsersOnlyException extends FatalErrorException
+{
+	/**
+	 * InternalUsersOnlyException constructor.
+	 *
+	 * @param string $message
+	 */
+	public function __construct($message = 'Feature only supported by internal users.')
+	{
+		parent::__construct($message);
+	}
+}

qa-src/Controllers/BaseController.php

@@ -18,12 +18,53 @@
 
 namespace Q2A\Controllers;
 
+use Q2A\Middleware\BaseMiddleware;
+
 abstract class BaseController
 {
-	// TODO: constructor taking Database class parameter
+	/** @var BaseMiddleware[string] */
+	private $middleware;
+
+	public function __construct()
+	{
+		// TODO: constructor taking Database class parameter
+		$this->middleware = array();
+	}
 
 	/**
-	 * Execute the given action with the given parameters on this controller.
+	 * Attach a middleware to one action or an array of actions. Use '*' to match all actions.
+	 *
+	 * @param BaseMiddleware $middleware
+	 * @param array|string $actions
+	 */
+	public function addMiddleware(BaseMiddleware $middleware, $actions = '*')
+	{
+		if (is_array($actions)) {
+			foreach ($actions as $action) {
+				$this->addMiddlewareToAction($middleware, $action);
+			}
+		} else { // If it is a string
+			$this->addMiddlewareToAction($middleware, $actions);
+		}
+	}
+
+	/**
+	 * @param BaseMiddleware $middleware
+	 * @param string $action
+	 */
+	private function addMiddlewareToAction(BaseMiddleware $middleware, $action)
+	{
+		if (!isset($this->middleware[$action])) {
+			$this->middleware[$action] = array();
+		}
+
+		$this->middleware[$action][] = $middleware;
+	}
+
+	/**
+	 * Execute the given action with the given parameters on this controller. after running all
+	 * middleware for the action. This method is expected to return a qa_content array or throw an
+	 * exception.
 	 *
 	 * @param string $action Action to execute
 	 * @param array $parameters Parameters to send to the action
@@ -32,6 +73,23 @@ abstract class BaseController
 	 */
 	public function executeAction($action, $parameters)
 	{
+		$this->executeMiddlewareForAction('*');
+		$this->executeMiddlewareForAction($action);
+
 		return call_user_func_array(array($this, $action), $parameters);
 	}
+
+	/**
+	 * @param string $action
+	 */
+	private function executeMiddlewareForAction($action)
+	{
+		if (!isset($this->middleware[$action])) {
+			return;
+		}
+
+		foreach ($this->middleware[$action] as $middleware) {
+			$middleware->handle();
+		}
+	}
 }

qa-src/Controllers/User/UserMessages.php

@@ -18,34 +18,36 @@
 
 namespace Q2A\Controllers\User;
 
+use Q2A\Http\PageNotFoundException;
+use Q2A\Middleware\Auth\InternalUsersOnly;
+
 require_once QA_INCLUDE_DIR . 'db/selects.php';
 require_once QA_INCLUDE_DIR . 'app/messages.php';
 
 class UserMessages extends \Q2A\Controllers\BaseController
 {
-	public function wall($handle)
+	public function __construct()
 	{
-		if (QA_FINAL_EXTERNAL_USERS) {
-			// Check we're not using single-sign on integration, which doesn't allow walls
-			qa_fatal_error('User accounts are handled by external code');
-			return;
-		}
+		parent::__construct();
 
+		$this->addMiddleware(new InternalUsersOnly());
+	}
+
+	public function wall($handle)
+	{
 		$userhtml = qa_html($handle);
 
 		$start = qa_get_start();
 
-
 		// Find the questions for this user
 
 		list($useraccount, $usermessages) = qa_db_select_with_pending(
 			qa_db_user_account_selectspec($handle, false),
 			qa_db_recent_messages_selectspec(null, null, $handle, false, qa_opt_if_loaded('page_size_wall'), $start)
 		);
-
-		if (!is_array($useraccount)) // check the user exists
-			return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
-
+		if (!is_array($useraccount)) { // check the user exists
+			throw new PageNotFoundException();
+		}
 
 		// Perform pagination
 
@@ -149,5 +151,4 @@ class UserMessages extends \Q2A\Controllers\BaseController
 
 		return $qa_content;
 	}
-
 }

qa-src/Controllers/User/UserPosts.php

@@ -18,6 +18,8 @@
 
 namespace Q2A\Controllers\User;
 
+use Q2A\Http\PageNotFoundException;
+
 require_once QA_INCLUDE_DIR . 'db/users.php';
 require_once QA_INCLUDE_DIR . 'db/selects.php';
 require_once QA_INCLUDE_DIR . 'app/users.php';
@@ -45,10 +47,9 @@ class UserPosts extends \Q2A\Controllers\BaseController
 			qa_db_user_recent_edit_qs_selectspec($loginuserid, $identifier)
 		);
 
-		if (!QA_FINAL_EXTERNAL_USERS && !is_array($useraccount)) // check the user exists
-			return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
-
-
+		if (!QA_FINAL_EXTERNAL_USERS && !is_array($useraccount)) { // check the user exists
+			throw new PageNotFoundException();
+		}
 		// Get information on user references
 
 		$questions = qa_any_sort_and_dedupe(array_merge($questions, $answerqs, $commentqs, $editqs));
@@ -115,8 +116,9 @@ class UserPosts extends \Q2A\Controllers\BaseController
 			qa_db_user_recent_qs_selectspec($loginuserid, $identifier, qa_opt_if_loaded('page_size_qs'), $start)
 		);
 
-		if (!QA_FINAL_EXTERNAL_USERS && !is_array($useraccount)) // check the user exists
-			return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
+		if (!QA_FINAL_EXTERNAL_USERS && !is_array($useraccount)) { // check the user exists
+			throw new PageNotFoundException();
+		}
 
 
 		// Get information on user questions
@@ -188,8 +190,9 @@ class UserPosts extends \Q2A\Controllers\BaseController
 			qa_db_user_recent_a_qs_selectspec($loginuserid, $identifier, qa_opt_if_loaded('page_size_activity'), $start)
 		);
 
-		if (!QA_FINAL_EXTERNAL_USERS && !is_array($useraccount)) // check the user exists
-			return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
+		if (!QA_FINAL_EXTERNAL_USERS && !is_array($useraccount)) { // check the user exists
+			throw new PageNotFoundException();
+		}
 
 
 		// Get information on user questions
@@ -254,12 +257,12 @@ class UserPosts extends \Q2A\Controllers\BaseController
 
 		if (QA_FINAL_EXTERNAL_USERS) {
 			$this->userid = qa_handle_to_userid($handle);
-			if (!isset($this->userid))
-				return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
+			if (!isset($this->userid)) { // check the user exists
+				throw new PageNotFoundException();
+			}
 
 			$usershtml = qa_get_users_html(array($this->userid), false, qa_path_to_root(), true);
 			$this->userhtml = @$usershtml[$this->userid];
-
 		} else
 			$this->userhtml = qa_html($handle);
 	}

qa-src/Controllers/User/UserProfile.php

@@ -18,6 +18,8 @@
 
 namespace Q2A\Controllers\User;
 
+use Q2A\Http\PageNotFoundException;
+
 require_once QA_INCLUDE_DIR . 'db/users.php';
 require_once QA_INCLUDE_DIR . 'db/selects.php';
 require_once QA_INCLUDE_DIR . 'app/users.php';
@@ -40,8 +42,9 @@ class UserProfile extends \Q2A\Controllers\BaseController
 
 		if (QA_FINAL_EXTERNAL_USERS) {
 			$userid = qa_handle_to_userid($handle);
-			if (!isset($userid))
-				return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
+			if (!isset($userid)) { // check the user exists
+				throw new PageNotFoundException();
+			}
 
 			$usershtml = qa_get_users_html(array($userid), false, qa_path_to_root(), true);
 			$userhtml = @$usershtml[$userid];
@@ -90,8 +93,9 @@ class UserProfile extends \Q2A\Controllers\BaseController
 		if (!QA_FINAL_EXTERNAL_USERS) { // if we're using integrated user management, we can know and show more
 			require_once QA_INCLUDE_DIR . 'app/messages.php';
 
-			if (!is_array($userpoints) && !is_array($useraccount))
-				return include QA_INCLUDE_DIR . 'qa-page-not-found.php';
+			if (!is_array($userpoints) && !is_array($useraccount)) { // check the user exists
+				throw new PageNotFoundException();
+			}
 
 			$userid = $useraccount['userid'];
 			$fieldseditable = false;

qa-src/Database/DbConnection.php

@@ -100,7 +100,7 @@ class DbConnection
 		}
 	}
 
-	public function query($query, $params=array())
+	public function query($query, $params = array())
 	{
 		try {
 			if (QA_DEBUG_PERFORMANCE) {
@@ -127,7 +127,7 @@ class DbConnection
 		}
 	}
 
-	protected function execute($query, $params=array())
+	protected function execute($query, $params = array())
 	{
 		$stmt = $this->pdo->prepare($query);
 

qa-src/Exceptions/ErrorMessageException.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Exceptions;
+
+use Exception;
+
+class ErrorMessageException extends Exception
+{
+	/**
+	 * ErrorMessageException constructor.
+	 *
+	 * @param string $message
+	 */
+	public function __construct($message = 'Error message exception.')
+	{
+		parent::__construct($message);
+	}
+}

qa-src/Exceptions/ExceptionHandler.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Exceptions;
+
+use Exception;
+use Q2A\Http\PageNotFoundException;
+
+require_once QA_INCLUDE_DIR . 'app/format.php';
+
+class ExceptionHandler
+{
+	public function __construct()
+	{
+	}
+
+	public function handle(Exception $exception)
+	{
+		if ($exception instanceof FatalErrorException) {
+			$this->handleFatalErrorException($exception);
+		} elseif ($exception instanceof PageNotFoundException) {
+			return $this->handlePageNotFoundException($exception);
+		} elseif ($exception instanceof ErrorMessageException) {
+			return $this->handleErrorMessageException($exception);
+		} else {
+			return $this->handleUnknownException($exception);
+		}
+	}
+
+	private function handleFatalErrorException(FatalErrorException $exception)
+	{
+		qa_fatal_error($exception->getMessage());
+	}
+
+	private function handlePageNotFoundException(PageNotFoundException $exception)
+	{
+		header('HTTP/1.0 404 Not Found');
+
+		$qa_content = $this->handleErrorMessageException($exception);
+		$qa_content['suggest_next'] = qa_html_suggest_qs_tags(qa_using_tags());
+
+		return $qa_content;
+	}
+
+	private function handleErrorMessageException(ErrorMessageException $exception)
+	{
+		$qa_content = qa_content_prepare();
+		$qa_content['error'] = $exception->getMessage();
+
+		return $qa_content;
+	}
+
+	private function handleUnknownException(Exception $exception)
+	{
+		return $this->handleErrorMessageException(new ErrorMessageException($exception->getMessage()));
+	}
+}

qa-src/Exceptions/FatalErrorException.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Exceptions;
+
+use Exception;
+
+class FatalErrorException extends Exception
+{
+	/**
+	 * FatalErrorException constructor.
+	 *
+	 * @param string $message
+	 */
+	public function __construct($message = 'Fatal error exception.')
+	{
+		parent::__construct($message);
+	}
+}

qa-src/Http/PageNotFoundException.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Http;
+
+use Q2A\Exceptions\ErrorMessageException;
+
+class PageNotFoundException extends ErrorMessageException
+{
+	/**
+	 * PageNotFoundException constructor.
+	 *
+	 * @param string $message
+	 */
+	public function __construct($message = null)
+	{
+		if (is_null($message)) {
+			$message = qa_lang_html('main/page_not_found');
+		}
+
+		parent::__construct($message);
+	}
+}

qa-src/Http/Route.php → qa-src/Http/Routing/Route.php

@@ -16,7 +16,7 @@
 	More about this license: http://www.question2answer.org/license.php
 */
 
-namespace Q2A\Http;
+namespace Q2A\Http\Routing;
 
 class Route
 {

qa-src/Http/Router.php → qa-src/Http/Routing/Router.php

@@ -16,7 +16,7 @@
 	More about this license: http://www.question2answer.org/license.php
 */
 
-namespace Q2A\Http;
+namespace Q2A\Http\Routing;
 
 class Router
 {

qa-src/Middleware/Auth/InternalUsersOnly.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Middleware\Auth;
+
+use Q2A\Auth\InternalUsersOnlyException;
+use Q2A\Middleware\BaseMiddleware;
+
+class InternalUsersOnly extends BaseMiddleware
+{
+	/**
+	 * Throw an exception if the current configuration is set to external users.
+	 *
+	 * @throws InternalUsersOnlyException
+	 */
+	public function handle()
+	{
+		if (QA_FINAL_EXTERNAL_USERS) {
+			throw new InternalUsersOnlyException('User accounts are handled by external code');
+		}
+	}
+}

qa-src/Middleware/BaseMiddleware.php

+<?php
+/*
+	Question2Answer by Gideon Greenspan and contributors
+	http://www.question2answer.org/
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	More about this license: http://www.question2answer.org/license.php
+*/
+
+namespace Q2A\Middleware;
+
+abstract class BaseMiddleware
+{
+	abstract public function handle();
+}