gnu-social/plugins/LinkbackPlugin.php

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<?php
/**
* Laconica, the distributed open-source microblogging tool
*
* Plugin to do linkbacks for notices containing links
*
* PHP version 5
*
* LICENCE: This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* @category Plugin
* @package Laconica
* @author Evan Prodromou <evan@controlyourself.ca>
* @copyright 2009 Control Yourself, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://laconi.ca/
*/
if (!defined('LACONICA')) {
exit(1);
}
require_once('Auth/Yadis/Yadis.php');
define('LINKBACKPLUGIN_VERSION', '0.1');
/**
* Plugin to do linkbacks for notices containing URLs
*
* After new notices are saved, we check their text for URLs. If there
* are URLs, we test each URL to see if it supports any
*
* @category Plugin
* @package Laconica
* @author Evan Prodromou <evan@controlyourself.ca>
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://laconi.ca/
*
* @see Event
*/
class LinkbackPlugin extends Plugin
{
var $notice = null;
function __construct()
{
parent::__construct();
}
function onEndNoticeSave($notice)
{
if ($notice->is_local == 1) {
// Try to avoid actually mucking with the
// notice content
$c = $notice->content;
$this->notice = $notice;
// Ignoring results
common_replace_urls_callback($c,
array($this, 'linkbackUrl'));
}
return true;
}
function linkbackUrl($url)
{
$orig = $url;
$url = htmlspecialchars_decode($orig);
$scheme = parse_url($url, PHP_URL_SCHEME);
if (!in_array($scheme, array('http', 'https'))) {
return $orig;
}
// XXX: Do a HEAD first to save some time/bandwidth
$fetcher = Auth_Yadis_Yadis::getHTTPFetcher();
$result = $fetcher->get($url,
array('User-Agent: ' . $this->userAgent(),
'Accept: application/html+xml,text/html'));
if (!in_array($result->status, array('200', '206'))) {
return $orig;
}
if (array_key_exists('X-Pingback', $result->headers)) {
$endpoint = $result->headers['X-Pingback'];
} else if (preg_match('/<link rel="pingback" href="([^"]+)" ?/?>/',
$result->body,
$match)) {
$endpoint = $match[1];
} else {
// XXX: do Trackback lookup
return $orig;
}
$this->pingback($url, $endpoint);
return $orig;
}
function pingback($url, $endpoint)
{
$args = array($this->notice->uri, $url);
$request = xmlrpc_encode_request('pingback.ping', $args);
$context = stream_context_create(array('http' => array('method' => "POST",
'header' =>
"Content-Type: text/xml\r\n".
"User-Agent: " . $this->userAgent(),
'content' => $request)));
$file = file_get_contents($endpoint, false, $context);
$response = xmlrpc_decode($file);
if (xmlrpc_is_fault($response)) {
common_log(LOG_WARNING,
"Pingback error for '$url' ($endpoint): ".
"$response[faultString] ($response[faultCode])");
} else {
common_log(LOG_INFO,
"Pingback success for '$url' ($endpoint): ".
"'$response'");
}
}
function userAgent()
{
return 'LinkbackPlugin/'.LINKBACKPLUGIN_VERSION .
' Laconica/' . LACONICA_VERSION;
}
}