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/>.

/**

 * Base class for dataformat.

 *

 * @package    core

 * @subpackage dataformat

 * @copyright  2016 Brendan Heywood (brendan@catalyst-au.net)

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

 */

namespace core\dataformat;

use coding_exception;

/**

 * Base class for dataformat.

 *

 * @package    core

 * @subpackage dataformat

 * @copyright  2016 Brendan Heywood (brendan@catalyst-au.net)

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

 */

abstract class base {

    /** @var $mimetype */

    protected $mimetype = "text/plain";

    /** @var $extension */

    protected $extension = ".txt";

    /** @var $filename */

    protected $filename = '';

    /** @var string The location to store the output content */

    protected $filepath = '';

    /**

     * Get the file extension

     *

     * @return string file extension

     */

    public function get_extension() {

        return $this->extension;

    }

    /**

     * Set download filename base

     *

     * @param string $filename

     */

    public function set_filename($filename) {

        $this->filename = $filename;

    }

    /**

     * Set file path when writing to file

     *

     * @param string $filepath

     * @throws coding_exception

     */

    public function set_filepath(string $filepath): void {

        $filedir = dirname($filepath);

        if (!is_writable($filedir)) {

            throw new coding_exception('File path is not writable');

        }

        $this->filepath = $filepath;

        // Some dataformat writers may expect filename to be set too.

        $this->set_filename(pathinfo($this->filepath, PATHINFO_FILENAME));

    }

    /**

     * Set the title of the worksheet inside a spreadsheet

     *

     * For some formats this will be ignored.

     *

     * @param string $title

     */

    public function set_sheettitle($title) {

    }

    /**

     * Output file headers to initialise the download of the file.

     */

    public function send_http_headers() {

        if (defined('BEHAT_SITE_RUNNING') || PHPUNIT_TEST) {

            // For text based formats - we cannot test the output with behat if we force a file download.

            return;

        }

        if (is_https()) {

            // HTTPS sites - watch out for IE! KB812935 and KB316431.

            header('Cache-Control: max-age=10');

            header('Pragma: ');

        } else {

            // Normal http - prevent caching at all cost.

            header('Cache-Control: private, must-revalidate, pre-check=0, post-check=0, max-age=0');

            header('Pragma: no-cache');

        }

        header('Expires: '. gmdate('D, d M Y H:i:s', 0) .' GMT');

        header("Content-Type: $this->mimetype\n");

        $filename = $this->filename . $this->get_extension();

        header("Content-Disposition: attachment; filename=\"$filename\"");

    }

    /**

     * Set the dataformat to be output to current file. Calling code must call {@see base::close_output_to_file()} when finished

     */

    public function start_output_to_file(): void {

        // Raise memory limit to ensure we can store the entire content. Start collecting output.

        raise_memory_limit(MEMORY_EXTRA);

        ob_start();

        $this->start_output();

    }

    /**

     * Write the start of the file.

     */

    public function start_output() {

        // Override me if needed.

    }

    /**

     * Write the start of the sheet we will be adding data to.

     *

     * @param array $columns

     */

    public function start_sheet($columns) {

        // Override me if needed.

    }

    /**

     * Method to define whether the dataformat supports export of HTML

     *

     * @return bool

     */

    public function supports_html(): bool {

        return false;

    }

    /**

     * Apply formatting to the cells of a given record

     *

     * @param array|\stdClass $record

     * @return array

     */

    protected function format_record($record): array {

        $record = (array)$record;

        // If the dataformat supports export of HTML, we need to allow them to manage embedded images.

        if ($this->supports_html()) {

            $record = array_map([$this, 'replace_pluginfile_images'], $record);

        }

        return $record;

    }

    /**

     * Given a stored_file, return a suitable source attribute for an img element in the export (or null to use the original)

     *

     * @param \stored_file $file

     * @return string|null

     */

    protected function export_html_image_source(\stored_file $file): ?string {

        return null;

    }

    /**

     * We need to locate all img tags within a given cell that match pluginfile URL's. Partly so the exported file will show

     * the image without requiring the user is logged in; and also to prevent some of the dataformats requesting the file

     * themselves, which is likely to fail due to them not having an active session

     *

     * @param string|null $content

     * @return string

     */

    protected function replace_pluginfile_images(?string $content): string {

        $content = (string)$content;

        // Examine content to see if it contains any HTML image tags.

        return preg_replace_callback('/(?<pre><img[^>]+src=")(?<source>[^"]*)(?<post>".*>)/i', function(array $matches) {

            $source = $matches['source'];

            // Now check if the image source looks like a pluginfile URL.

            if (preg_match('/pluginfile.php\/(?<context>\d+)\/(?<component>[^\/]+)\/(?<filearea>[^\/]+)\/(?:(?<itemid>\d+)\/)?' .

                    '(?<path>.*)/u', $source, $args)) {

                $context = $args['context'];

                $component = clean_param($args['component'], PARAM_COMPONENT);

                $filearea = clean_param($args['filearea'], PARAM_AREA);

                $itemid = $args['itemid'] ?: 0;

                $path = clean_param(urldecode($args['path']), PARAM_PATH);

                // Try and get the matching file from storage, allow the dataformat to define the replacement source.

                $fullpath = "/{$context}/{$component}/{$filearea}/{$itemid}/{$path}";

                if ($file = get_file_storage()->get_file_by_hash(sha1($fullpath))) {

                    $exportsource = $this->export_html_image_source($file);

                    if ($exportsource) {

                        $source = $exportsource;

                    }

                }

            }

            return $matches['pre'] . $source . $matches['post'];

        }, $content);

    }

    /**

     * Write a single record

     *

     * @param array $record

     * @param int $rownum

     */

    abstract public function write_record($record, $rownum);

    /**

     * Write the end of the sheet containing the data.

     *

     * @param array $columns

     */

    public function close_sheet($columns) {

        // Override me if needed.

    }

    /**

     * Write the end of the file.

     */

    public function close_output() {

        // Override me if needed.

    }

    /**

     * Write the data to disk. Calling code should have previously called {@see base::start_output_to_file()}

     *

     * @return bool Whether the write succeeded

     */

    public function close_output_to_file(): bool {

        $this->close_output();

        $filecontent = ob_get_contents();

        ob_end_clean();

        return file_put_contents($this->filepath, $filecontent) !== false;

    }

}