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/>.

/**

 * Class containing utility methods for dataformats

 *

 * @package     core

 * @copyright   2020 Paul Holden <paulh@moodle.com>

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

 */

namespace core;

use coding_exception;

use core_php_time_limit;

use stored_file;

/**

 * Dataformat utility class

 *

 * @package     core

 * @copyright   2020 Paul Holden <paulh@moodle.com>

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

 */

class dataformat {

    /**

     * Return an instance of a dataformat writer from given dataformat type

     *

     * @param string $dataformat

     * @return dataformat\base

     * @throws coding_exception

     */

    protected static function get_format_instance(string $dataformat): \core\dataformat\base {

        $classname = 'dataformat_' . $dataformat . '\writer';

        if (!class_exists($classname)) {

            throw new coding_exception('Invalid dataformat', $dataformat);

        }

        return new $classname();

    }

    /**

     * Sends a formatted data file to the browser

     *

     * @param string $filename

     * @param string $dataformat

     * @param array $columns

     * @param Iterable $iterator

     * @param callable|null $callback Optional callback method to apply to each record prior to writing, which accepts two

     *      parameters as such: function($record, bool $supportshtml) returning formatted record

     * @throws coding_exception

     */

    public static function download_data(string $filename, string $dataformat, array $columns, Iterable $iterator,

            callable $callback = null): void {

        if (ob_get_length()) {

            throw new coding_exception('Output can not be buffered before calling download_data()');

        }

        $format = self::get_format_instance($dataformat);

        // The data format export could take a while to generate.

        core_php_time_limit::raise();

        // Close the session so that the users other tabs in the same session are not blocked.

        \core\session\manager::write_close();

        // If this file was requested from a form, then mark download as complete (before sending headers).

        \core_form\util::form_download_complete();

        $format->set_filename($filename);

        $format->send_http_headers();

        $format->start_output();

        $format->start_sheet($columns);

        $rownum = 0;

        foreach ($iterator as $row) {

            if (is_callable($callback)) {

                $row = $callback($row, $format->supports_html());

            }

            if ($row === null) {

                continue;

            }

            $format->write_record($row, $rownum++);

        }

        $format->close_sheet($columns);

        $format->close_output();

    }

    /**

     * Writes a formatted data file with specified filename

     *

     * @param string $filename

     * @param string $dataformat

     * @param array $columns

     * @param Iterable $iterator

     * @param callable|null $callback

     * @return string Complete path to the file on disk

     */

    public static function write_data(string $filename, string $dataformat, array $columns, Iterable $iterator,

            callable $callback = null): string {

        $format = self::get_format_instance($dataformat);

        // The data format export could take a while to generate.

        core_php_time_limit::raise();

        // Close the session so that the users other tabs in the same session are not blocked.

        \core\session\manager::write_close();

        $filepath = make_request_directory() . '/' . $filename . $format->get_extension();

        $format->set_filepath($filepath);

        $format->start_output_to_file();

        $format->start_sheet($columns);

        $rownum = 0;

        foreach ($iterator as $row) {

            if (is_callable($callback)) {

                $row = $callback($row, $format->supports_html());

            }

            if ($row === null) {

                continue;

            }

            $format->write_record($row, $rownum++);

        }

        $format->close_sheet($columns);

        $format->close_output_to_file();

        return $filepath;

    }

    /**

     * Writes a formatted data file to file storage

     *

     * @param array $filerecord File record for storage, 'filename' extension should be omitted as it's added by the dataformat

     * @param string $dataformat

     * @param array $columns

     * @param Iterable $iterator Iterable set of records to write

     * @param callable|null $callback Optional callback method to apply to each record prior to writing

     * @return stored_file

     */

    public static function write_data_to_filearea(array $filerecord, string $dataformat, array $columns, Iterable $iterator,

            callable $callback = null): stored_file {

        $filepath = self::write_data($filerecord['filename'], $dataformat, $columns, $iterator, $callback);

        // Update filename of returned file record.

        $filerecord['filename'] = basename($filepath);

        return get_file_storage()->create_file_from_pathname($filerecord, $filepath);

    }

}