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<?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;
}
}