Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle 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 3 of the License, or

// (at your option) any later version.

//

// Moodle 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.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace core\output;

use coding_exception;

/**

 * This class solves the problem of how to initialise $OUTPUT.

 *

 * The problem is caused be two factors

 * <ol>

 * <li>On the one hand, we cannot be sure when output will start. In particular,

 * an error, which needs to be displayed, could be thrown at any time.</li>

 * <li>On the other hand, we cannot be sure when we will have all the information

 * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which

 * (potentially) depends on the current course, course categories, and logged in user.

 * It also depends on whether the current page requires HTTPS.</li>

 * </ol>

 *

 * So, it is hard to find a single natural place during Moodle script execution,

 * which we can guarantee is the right time to initialise $OUTPUT. Instead we

 * adopt the following strategy

 * <ol>

 * <li>We will initialise $OUTPUT the first time it is used.</li>

 * <li>If, after $OUTPUT has been initialised, the script tries to change something

 * that $OUTPUT depends on, we throw an exception making it clear that the script

 * did something wrong.

 * </ol>

 *

 * The only problem with that is, how do we initialise $OUTPUT on first use if,

 * it is going to be used like $OUTPUT->somthing(...)? Well that is where this

 * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,

 * when any method is called on that object, we initialise $OUTPUT, and pass the call on.

 *

 * Note that this class is used before lib/outputlib.php has been loaded, so we

 * must be careful referring to classes/functions from there, they may not be

 * defined yet, and we must avoid fatal errors.

 *

 * @package    core

 * @copyright 2009 Tim Hunt

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 * @since     Moodle 2.0

 */

class bootstrap_renderer {

    /**

     * Handles re-entrancy. Without this, errors or debugging output that occur

     * during the initialisation of $OUTPUT, cause infinite recursion.

     *

     * @var bool

     */

    protected $initialising = false;

    /**

     * Whether output has started yet.

     *

     * @return bool true if the header has been printed.

     */

    public function has_started() {

        return false;

    }

    /**

     * Constructor - to be used by core code only.

     *

     * @param string $method The method to call

     * @param array $arguments Arguments to pass to the method being called

     * @return string

     */

    public function __call($method, $arguments) {

        // phpcs:disable moodle.PHP.ForbiddenGlobalUse.BadGlobal

        global $OUTPUT, $PAGE;

        $recursing = false;

        if ($method == 'notification') {

            // Catch infinite recursion caused by debugging output during print_header.

            // phpcs:ignore PHPCompatibility.FunctionUse.ArgumentFunctionsReportCurrentValue.NeedsInspection

            $backtrace = debug_backtrace();

            array_shift($backtrace);

            array_shift($backtrace);

            $recursing = is_early_init($backtrace);

        }

        $earlymethods = [

            'fatal_error' => 'early_error',

            'notification' => 'early_notification',

        ];

        // If lib/outputlib.php has been loaded, call it.

        if (!empty($PAGE) && !$recursing) {

            if (array_key_exists($method, $earlymethods)) {

                // Prevent PAGE->context warnings - exceptions might appear before we set any context.

                $PAGE->set_context(null);

            }

            $PAGE->initialise_theme_and_output();

            return call_user_func_array([$OUTPUT, $method], $arguments);

        }

        $this->initialising = true;

        // Too soon to initialise $OUTPUT, provide a couple of key methods.

        if (array_key_exists($method, $earlymethods)) {

            return call_user_func_array([self::class, $earlymethods[$method]], $arguments);

        }

        throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');

    }

    /**

     * Returns nicely formatted error message in a div box.

     *

     * @param string $message error message

     * @param ?string $moreinfourl (ignored in early errors)

     * @param ?string $link (ignored in early errors)

     * @param ?array $backtrace

     * @param ?string $debuginfo

     * @return string

     */

    public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {

        global $CFG;

        $content = "<div class='alert-danger'>$message</div>";

        // Check whether debug is set.

        $debug = (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER);

        // Also check we have it set in the config file. This occurs if the method to read the config table from the

        // database fails, reading from the config table is the first database interaction we have.

        $debug = $debug || (!empty($CFG->config_php_settings['debug'])  && $CFG->config_php_settings['debug'] >= DEBUG_DEVELOPER );

        if ($debug) {

            if (!empty($debuginfo)) {

                // Remove all nasty JS.

                if (function_exists('s')) { // Function may be not available for some early errors.

                    $debuginfo = s($debuginfo);

                } else {

                    // Because weblib is not available for these early errors, we

                    // just duplicate s() code here to be safe.

                    $debuginfo = preg_replace(

                        '/&#(\d+|x[0-9a-f]+);/i',

                        '&#$1;',

                        htmlspecialchars($debuginfo, ENT_QUOTES | ENT_HTML401 | ENT_SUBSTITUTE)

                    );

                }

                $debuginfo = str_replace("\n", '<br />', $debuginfo); // Keep newlines.

                $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';

            }

            if (!empty($backtrace)) {

                $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';

            }

        }

        return $content;

    }

    /**

     * This function should only be called by this class, or from exception handlers

     *

     * @param string $message error message

     * @param string $moreinfourl (ignored in early errors)

     * @param string $link (ignored in early errors)

     * @param array $backtrace

     * @param string $debuginfo extra information for developers

     * @return ?string

     */

    public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null, $errorcode = null) {

        global $CFG;

        if (CLI_SCRIPT) {

            echo "!!! $message !!!\n";

            if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {

                if (!empty($debuginfo)) {

                    echo "\nDebug info: $debuginfo";

                }

                if (!empty($backtrace)) {

                    echo "\nStack trace: " . format_backtrace($backtrace, true);

                }

            }

            return;

        } else if (AJAX_SCRIPT) {

            $error = (object) [

                'error' => $message,

                'stacktrace' => null,

                'debuginfo' => null,

                'errorcode' => $errorcode,

            ];

            if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {

                if (!empty($debuginfo)) {

                    $error->debuginfo = $debuginfo;

                }

                if (!empty($backtrace)) {

                    $error->stacktrace = format_backtrace($backtrace, true);

                }

            }

            @header('Content-Type: application/json; charset=utf-8');

            echo json_encode($error);

            return;

        }

        // In the name of protocol correctness, monitoring and performance

        // profiling, set the appropriate error headers for machine consumption.

        $protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');

        @header($protocol . ' 500 Internal Server Error');

        // Better disable any caching.

        @header('Content-Type: text/html; charset=utf-8');

        @header('X-UA-Compatible: IE=edge');

        @header('Cache-Control: no-store, no-cache, must-revalidate');

        @header('Cache-Control: post-check=0, pre-check=0', false);

        @header('Pragma: no-cache');

        @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');

        @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');

        if (function_exists('get_string')) {

            $strerror = get_string('error');

        } else {

            $strerror = 'Error';

        }

        $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);

        return self::plain_page($strerror, $content);

    }

    /**

     * Early notification message

     *

     * @param string $message

     * @param string $classes usually notifyproblem or notifysuccess

     * @return string

     */

    public static function early_notification($message, $classes = 'notifyproblem') {

        return '<div class="' . $classes . '">' . $message . '</div>';

    }

    /**

     * Page should redirect message.

     *

     * @param string $encodedurl redirect url

     * @return string

     */

    public static function plain_redirect_message($encodedurl) {

        $message = '<div style="margin-top: 3em; margin-left:auto; margin-right:auto; text-align:center;">';

        $message .= get_string('pageshouldredirect') . '<br /><a href="';

        $message .= $encodedurl . '">' . get_string('continue') . '</a></div>';

        return self::plain_page(get_string('redirect'), $message);

    }

    /**

     * Early redirection page, used before full init of $PAGE global.

     *

     * @param string $encodedurl redirect url

     * @param string $message redirect message

     * @param int $delay time in seconds

     * @return string redirect page

     */

    public static function early_redirect_message($encodedurl, $message, $delay) {

        $meta = '<meta http-equiv="refresh" content="' . $delay . '; url=' . $encodedurl . '" />';

        $content = self::early_error_content($message, null, null, null);

        $content .= self::plain_redirect_message($encodedurl);

        return self::plain_page(get_string('redirect'), $content, $meta);

    }

    /**

     * Output basic html page.

     *

     * @param string $title page title

     * @param string $content page content

     * @param string $meta meta tag

     * @return string html page

     */

    public static function plain_page($title, $content, $meta = '') {

        global $CFG;

        if (function_exists('get_string') && function_exists('get_html_lang')) {

            $htmllang = get_html_lang();

        } else {

            $htmllang = '';

        }

        $footer = '';

        if (function_exists('get_performance_info')) { // Function may be not available for some early errors.

            if (MDL_PERF_TEST) {

                $perfinfo = get_performance_info();

                $footer = '<footer>' . $perfinfo['html'] . '</footer>';

            }

        }

        ob_start();

        include($CFG->dirroot . '/error/plainpage.php');

        $html = ob_get_contents();

        ob_end_clean();

        return $html;

    }

}

// Alias this class to the old name.

// This file will be autoloaded by the legacyclasses autoload system.

// In future all uses of this class will be corrected and the legacy references will be removed.

class_alias(bootstrap_renderer::class, \bootstrap_renderer::class);