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/>.

/**

 * Minimalistic library, usable even when no other moodle libs are loaded.

 *

 * The only library that gets loaded if you define ABORT_AFTER_CONFIG

 * before including main config.php. You can resume normal script operation

 * if you define ABORT_AFTER_CONFIG_CANCEL and require the setup.php

 *

 * @package   core

 * @copyright 2009 Petr Skoda (skodak)

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

 */

/**

 * Minimalistic parameter validation function.

 * Can not use optional param because moodlelib.php is not loaded yet

 * @param string $name

 * @param mixed $default

 * @param string $type

 * @return mixed

 */

function min_optional_param($name, $default, $type) {

    if (isset($_GET[$name])) {

        $value = $_GET[$name];

    } else if (isset($_GET['amp;'.$name])) {

        // very, very, very ugly hack, unfortunately $OUTPUT->pix_url() is not used properly in javascript code :-(

        $value = $_GET['amp;'.$name];

    } else if (isset($_POST[$name])) {

        $value = $_POST[$name];

    } else {

        return $default;

    }

    return min_clean_param($value, $type);

}

/**

 * Minimalistic parameter cleaning function.

 *

 * Note: Can not use optional param because moodlelib.php is not loaded yet.

 *

 * @param string $value

 * @param string $type

 * @return mixed

 */

function min_clean_param($value, $type) {

    switch($type) {

        case 'RAW':      $value = min_fix_utf8((string)$value);

                         break;

        case 'INT':      $value = (int)$value;

                         break;

        case 'SAFEDIR':  $value = preg_replace('/[^a-zA-Z0-9_-]/', '', $value);

                         break;

        case 'SAFEPATH': $value = preg_replace('/[^a-zA-Z0-9\/\._-]/', '', $value);

                         $value = preg_replace('/\.+/', '.', $value);

                         $value = preg_replace('#/+#', '/', $value);

                         break;

        default:         die("Coding error: incorrect parameter type specified ($type).");

    }

    return $value;

}

/**

 * Minimalistic UTF-8 sanitisation.

 *

 * Note: This duplicates fix_utf8() intentionally for now.

 *

 * @param string $value

 * @return string

 */

function min_fix_utf8($value) {

    // No null bytes expected in our data, so let's remove it.

    $value = str_replace("\0", '', $value);

    static $buggyiconv = null;

    if ($buggyiconv === null) {

        set_error_handler(function () {

            return true;

        });

        $buggyiconv = (!function_exists('iconv') or iconv('UTF-8', 'UTF-8//IGNORE', '100'.chr(130).'€') !== '100€');

        restore_error_handler();

    }

    if ($buggyiconv) {

        if (function_exists('mb_convert_encoding')) {

            $subst = mb_substitute_character();

            mb_substitute_character('none');

            $result = mb_convert_encoding($value, 'utf-8', 'utf-8');

            mb_substitute_character($subst);

        } else {

            // Warn admins on admin/index.php page.

            $result = $value;

        }

    } else {

        $result = @iconv('UTF-8', 'UTF-8//IGNORE', $value);

    }

    return $result;

}

/**

 * This method tries to enable output compression if possible.

 * This function must be called before any output or headers.

 *

 * (IE6 is not supported at all.)

 *

 * @return boolean, true if compression enabled

 */

function min_enable_zlib_compression() {

    if (headers_sent()) {

        return false;

    }

    // zlib.output_compression is preferred over ob_gzhandler()

    if (!empty($_SERVER['HTTP_USER_AGENT']) and strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE 6') !== false) {

        ini_set('zlib.output_compression', 'Off');

        if (function_exists('apache_setenv')) {

            apache_setenv('no-gzip', 1);

        }

        return false;

    }

    ini_set('output_handler', '');

    /*

     * docs clearly say 'on' means enable and number means size of buffer,

     * but unfortunately some PHP version break when we set 'on' here.

     * 1 probably sets chunk size to 4096. our CSS and JS scripts are much bigger,

     * so let's try some bigger sizes.

     */

    ini_set('zlib.output_compression', 65536);

    return true;

}

/**

 * Returns the slashargument part of the URL.

 *

 * Note: ".php" is NOT allowed in slasharguments,

 *       it is intended for ASCII characters only.

 *

 * @param boolean $clean - Should we do cleaning on this path argument. If you set this

 *                         to false you MUST be very careful and do the cleaning manually.

 * @return string

 */

function min_get_slash_argument($clean = true) {

    // Note: This code has to work in the same cases as normal get_file_argument(),

    //       but at the same time it may be simpler because we do not have to deal

    //       with encodings and other tricky stuff.

    $relativepath = '';

    if (!empty($_GET['file']) and strpos($_GET['file'], '/') === 0) {

        // Server is using url rewriting, most probably IIS.

        // Always clean the result of this function as it may be used in unsafe calls to send_file.

        $relativepath = $_GET['file'];

        if ($clean) {

            $relativepath = min_clean_param($relativepath, 'SAFEPATH');

        }

        return $relativepath;

    } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {

        if (isset($_SERVER['PATH_INFO']) and $_SERVER['PATH_INFO'] !== '') {

            $relativepath = urldecode($_SERVER['PATH_INFO']);

        }

    } else {

        if (isset($_SERVER['PATH_INFO'])) {

            $relativepath = $_SERVER['PATH_INFO'];

        }

    }

    $matches = null;

    if (preg_match('|^.+\.php(.*)$|i', $relativepath, $matches)) {

        $relativepath = $matches[1];

    }

    // Always clean the result of this function as it may be used in unsafe calls to send_file.

    if ($clean) {

        $relativepath = min_clean_param($relativepath, 'SAFEPATH');

    }

    return $relativepath;

}

/**

 * Get the lowest possible currently valid revision number.

 *

 * This is based on the current Moodle version.

 *

 * @return int Unix timestamp

 */

function min_get_minimum_revision(): int {

    static $timestamp = null;

    // Days that will be deducted.

    // Avoids errors when date comparisons are made at time of packaging for next release.

    $tolerancedays = 2;

    if ($timestamp === null) {

        global $CFG;

        require("{$CFG->dirroot}/version.php");

        // Get YYYYMMDD from version.

        $datestring = floor($version / 100);

        // Parse the date components.

        $year = intval(substr($datestring, 0, 4));

        $month = intval(substr($datestring, 4, 2));

        $day = intval(substr($datestring, 6, 2)) - $tolerancedays;

        // Return converted GMT Unix timestamp.

        $timestamp = gmmktime(0, 0, 0, $month, $day, $year);

    }

    return $timestamp;

}

/**

 * Get the highest possible currently valid revision number.

 *

 * This is based on the current time, allowing for a small amount of clock skew between servers.

 *

 * Future values beyond the clock skew are not allowed to avoid the possibility of cache poisoning.

 *

 * @return int

 */

function min_get_maximum_revision(): int {

    return time() + 60;

}

/**

 * Helper function to determine if the given revision number is valid.

 *

 * @param int $revision A numeric revision to check for validity

 * @return bool Whether the revision is valid

 */

function min_is_revision_valid_and_current(int $revision): bool {

    // Invalid revision.

    if ($revision <= 0) {

        return false;

    }

    // Check revision is within range.

    return $revision >= min_get_minimum_revision() && $revision <= min_get_maximum_revision();

}