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<?php
/**
* @author Bart Visscher <bartv@thisnet.nl>
* @author Felix Moeller <mail@felixmoeller.de>
* @author Lukas Reschke <lukas@owncloud.com>
* @author Morris Jobke <hey@morrisjobke.de>
* @author Robin Appelman <icewind@owncloud.com>
* @author Thomas Müller <thomas.mueller@tmit.eu>
* @author Vincent Petry <pvince81@owncloud.com>
*
* @copyright Copyright (c) 2016, ownCloud, Inc.
* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
/**
* wrapper for server side events (http://en.wikipedia.org/wiki/Server-sent_events)
* includes a fallback for older browsers and IE
*
* use server side events with caution, to many open requests can hang the server
*/
class OC_EventSource implements \OCP\IEventSource {
/**
* @var bool
*/
private $fallback;
/**
* @var int
*/
private $fallBackId = 0;
/**
* @var bool
*/
private $started = false;
protected function init() {
if ($this->started) {
return;
}
$this->started = true;
// prevent php output buffering, caching and nginx buffering
OC_Util::obEnd();
header('Cache-Control: no-cache');
header('X-Accel-Buffering: no');
$this->fallback = isset($_GET['fallback']) and $_GET['fallback'] == 'true';
if ($this->fallback) {
$this->fallBackId = (int)$_GET['fallback_id'];
/**
* FIXME: The default content-security-policy of ownCloud forbids inline
* JavaScript for security reasons. IE starting on Windows 10 will
* however also obey the CSP which will break the event source fallback.
*
* As a workaround thus we set a custom policy which allows the execution
* of inline JavaScript.
*
* @link https://github.com/owncloud/core/issues/14286
*/
header("Content-Security-Policy: default-src 'none'; script-src 'unsafe-inline'");
header("Content-Type: text/html");
echo str_repeat('<span></span>' . PHP_EOL, 10); //dummy data to keep IE happy
} else {
header("Content-Type: text/event-stream");
}
if (!(\OC::$server->getRequest()->passesCSRFCheck())) {
$this->send('error', 'Possible CSRF attack. Connection will be closed.');
$this->close();
exit();
}
flush();
}
/**
* send a message to the client
*
* @param string $type
* @param mixed $data
*
* @throws \BadMethodCallException
* if only one parameter is given, a typeless message will be send with that parameter as data
*/
public function send($type, $data = null) {
if ($data and !preg_match('/^[A-Za-z0-9_]+$/', $type)) {
throw new BadMethodCallException('Type needs to be alphanumeric ('. $type .')');
}
$this->init();
if (is_null($data)) {
$data = $type;
$type = null;
}
if ($this->fallback) {
$response = '<script type="text/javascript">window.parent.OC.EventSource.fallBackCallBack('
. $this->fallBackId . ',"' . $type . '",' . OCP\JSON::encode($data) . ')</script>' . PHP_EOL;
echo $response;
} else {
if ($type) {
echo 'event: ' . $type . PHP_EOL;
}
echo 'data: ' . OCP\JSON::encode($data) . PHP_EOL;
}
echo PHP_EOL;
flush();
}
/**
* close the connection of the event source
*/
public function close() {
$this->send('__internal__', 'close'); //server side closing can be an issue, let the client do it
}
}
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