forked from GNUsocial/gnu-social
466 lines
12 KiB
PHP
466 lines
12 KiB
PHP
<?php
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/**
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* StatusNet - the distributed open-source microblogging tool
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* Copyright (C) 2010, StatusNet, Inc.
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*
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* Use Hammer discovery stack to find out interesting things about an URI
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*
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* PHP version 5
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* @category Discovery
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* @package StatusNet
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* @author James Walker <james@status.net>
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* @copyright 2010 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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/**
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* This class implements LRDD-based service discovery based on the "Hammer Draft"
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* (including webfinger)
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*
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* @category Discovery
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* @package StatusNet
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* @author James Walker <james@status.net>
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* @copyright 2010 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*
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* @see http://groups.google.com/group/webfinger/browse_thread/thread/9f3d93a479e91bbf
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*/
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class Discovery
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{
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const LRDD_REL = 'lrdd';
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const PROFILEPAGE = 'http://webfinger.net/rel/profile-page';
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const UPDATESFROM = 'http://schemas.google.com/g/2010#updates-from';
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const HCARD = 'http://microformats.org/profile/hcard';
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public $methods = array();
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/**
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* Constructor for a discovery object
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*
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* Registers different discovery methods.
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*
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* @return Discovery this
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*/
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public function __construct()
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{
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$this->registerMethod('Discovery_LRDD_Host_Meta');
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$this->registerMethod('Discovery_LRDD_Link_Header');
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$this->registerMethod('Discovery_LRDD_Link_HTML');
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}
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/**
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* Register a discovery class
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*
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* @param string $class Class name
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*
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* @return void
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*/
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public function registerMethod($class)
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{
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$this->methods[] = $class;
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}
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/**
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* Given a "user id" make sure it's normalized to either a webfinger
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* acct: uri or a profile HTTP URL.
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*
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* @param string $user_id User ID to normalize
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*
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* @return string normalized acct: or http(s)?: URI
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*/
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public static function normalize($user_id)
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{
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if (substr($user_id, 0, 5) == 'http:' ||
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substr($user_id, 0, 6) == 'https:' ||
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substr($user_id, 0, 5) == 'acct:') {
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return $user_id;
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}
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if (strpos($user_id, '@') !== false) {
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return 'acct:' . $user_id;
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}
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return 'http://' . $user_id;
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}
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/**
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* Determine if a string is a Webfinger ID
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*
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* Webfinger IDs look like foo@example.com or acct:foo@example.com
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*
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* @param string $user_id ID to check
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*
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* @return boolean true if $user_id is a Webfinger, else false
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*/
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public static function isWebfinger($user_id)
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{
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$uri = Discovery::normalize($user_id);
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return (substr($uri, 0, 5) == 'acct:');
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}
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/**
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* Given a user ID, return the first available XRD
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*
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* @param string $id User ID URI
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*
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* @return XRD XRD object for the user
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*/
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public function lookup($id)
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{
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// Normalize the incoming $id to make sure we have a uri
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$uri = $this->normalize($id);
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foreach ($this->methods as $class) {
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$links = call_user_func(array($class, 'discover'), $uri);
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if ($link = Discovery::getService($links, Discovery::LRDD_REL)) {
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// Load the LRDD XRD
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if (!empty($link['template'])) {
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$xrd_uri = Discovery::applyTemplate($link['template'], $uri);
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} else {
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$xrd_uri = $link['href'];
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}
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$xrd = $this->fetchXrd($xrd_uri);
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if ($xrd) {
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return $xrd;
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}
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}
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}
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// TRANS: Exception.
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throw new Exception(sprintf(_('Unable to find services for %s.'), $id));
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}
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/**
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* Given an array of links, returns the matching service
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*
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* @param array $links Links to check
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* @param string $service Service to find
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*
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* @return array $link assoc array representing the link
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*/
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public static function getService($links, $service)
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{
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if (!is_array($links)) {
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return false;
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}
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foreach ($links as $link) {
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if ($link['rel'] == $service) {
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return $link;
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}
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}
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}
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/**
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* Apply a template using an ID
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*
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* Replaces {uri} in template string with the ID given.
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*
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* @param string $template Template to match
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* @param string $id User ID to replace with
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*
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* @return string replaced values
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*/
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public static function applyTemplate($template, $id)
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{
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$template = str_replace('{uri}', urlencode($id), $template);
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return $template;
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}
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/**
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* Fetch an XRD file and parse
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*
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* @param string $url URL of the XRD
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*
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* @return XRD object representing the XRD file
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*/
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public static function fetchXrd($url)
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{
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try {
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$client = new HTTPClient();
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$response = $client->get($url);
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} catch (HTTP_Request2_Exception $e) {
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return false;
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}
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if ($response->getStatus() != 200) {
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return false;
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}
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return XRD::parse($response->getBody());
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}
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}
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/**
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* Abstract interface for discovery
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*
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* Objects that implement this interface can retrieve an array of
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* XRD links for the URI.
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*
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* @category Discovery
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* @package StatusNet
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* @author James Walker <james@status.net>
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* @copyright 2010 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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interface Discovery_LRDD
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{
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/**
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* Discover interesting info about the URI
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*
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* @param string $uri URI to inquire about
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*
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* @return array Links in the XRD file
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*/
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public function discover($uri);
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}
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/**
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* Implementation of discovery using host-meta file
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*
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* Discovers XRD file for a user by going to the organization's
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* host-meta file and trying to find a template for LRDD.
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*
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* @category Discovery
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* @package StatusNet
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* @author James Walker <james@status.net>
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* @copyright 2010 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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class Discovery_LRDD_Host_Meta implements Discovery_LRDD
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{
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/**
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* Discovery core method
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*
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* For Webfinger and HTTP URIs, fetch the host-meta file
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* and look for LRDD templates
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*
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* @param string $uri URI to inquire about
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*
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* @return array Links in the XRD file
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*/
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public function discover($uri)
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{
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if (Discovery::isWebfinger($uri)) {
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// We have a webfinger acct: - start with host-meta
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list($name, $domain) = explode('@', $uri);
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} else {
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$domain = parse_url($uri, PHP_URL_HOST);
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}
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$url = 'http://'. $domain .'/.well-known/host-meta';
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$xrd = Discovery::fetchXrd($url);
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if ($xrd) {
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if ($xrd->host != $domain) {
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return false;
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}
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return $xrd->links;
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}
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}
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}
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/**
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* Implementation of discovery using HTTP Link header
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*
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* Discovers XRD file for a user by fetching the URL and reading any
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* Link: headers in the HTTP response.
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*
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* @category Discovery
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* @package StatusNet
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* @author James Walker <james@status.net>
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* @copyright 2010 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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class Discovery_LRDD_Link_Header implements Discovery_LRDD
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{
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/**
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* Discovery core method
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*
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* For HTTP IDs fetch the URL and look for Link headers.
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*
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* @param string $uri URI to inquire about
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*
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* @return array Links in the XRD file
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*
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* @todo fail out of Webfinger URIs faster
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*/
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public function discover($uri)
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{
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try {
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$client = new HTTPClient();
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$response = $client->get($uri);
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} catch (HTTP_Request2_Exception $e) {
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return false;
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}
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if ($response->getStatus() != 200) {
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return false;
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}
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$link_header = $response->getHeader('Link');
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if (!$link_header) {
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// return false;
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}
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return array(Discovery_LRDD_Link_Header::parseHeader($link_header));
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}
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/**
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* Given a string or array of headers, returns XRD-like assoc array
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*
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* @param string|array $header string or array of strings for headers
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*
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* @return array Link header in XRD-like format
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*/
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protected static function parseHeader($header)
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{
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$lh = new LinkHeader($header);
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return array('href' => $lh->href,
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'rel' => $lh->rel,
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'type' => $lh->type);
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}
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}
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/**
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* Implementation of discovery using HTML <link> element
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*
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* Discovers XRD file for a user by fetching the URL and reading any
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* <link> elements in the HTML response.
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*
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* @category Discovery
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* @package StatusNet
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* @author James Walker <james@status.net>
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* @copyright 2010 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
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* @link http://status.net/
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*/
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class Discovery_LRDD_Link_HTML implements Discovery_LRDD
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{
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/**
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* Discovery core method
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*
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* For HTTP IDs, fetch the URL and look for <link> elements
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* in the HTML response.
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*
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* @param string $uri URI to inquire about
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*
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* @return array Links in XRD-ish assoc array
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*
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* @todo fail out of Webfinger URIs faster
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*/
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public function discover($uri)
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{
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try {
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$client = new HTTPClient();
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$response = $client->get($uri);
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} catch (HTTP_Request2_Exception $e) {
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return false;
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}
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if ($response->getStatus() != 200) {
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return false;
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}
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return Discovery_LRDD_Link_HTML::parse($response->getBody());
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}
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/**
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* Parse HTML and return <link> elements
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*
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* Given an HTML string, scans the string for <link> elements
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*
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* @param string $html HTML to scan
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*
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* @return array array of associative arrays in XRD-ish format
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*/
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public function parse($html)
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{
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$links = array();
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preg_match('/<head(\s[^>]*)?>(.*?)<\/head>/is', $html, $head_matches);
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$head_html = $head_matches[2];
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preg_match_all('/<link\s[^>]*>/i', $head_html, $link_matches);
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foreach ($link_matches[0] as $link_html) {
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$link_url = null;
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$link_rel = null;
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$link_type = null;
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preg_match('/\srel=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $rel_matches);
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if ( isset($rel_matches[3]) ) {
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$link_rel = $rel_matches[3];
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} else if ( isset($rel_matches[1]) ) {
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$link_rel = $rel_matches[1];
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}
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preg_match('/\shref=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $href_matches);
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if ( isset($href_matches[3]) ) {
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$link_uri = $href_matches[3];
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} else if ( isset($href_matches[1]) ) {
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$link_uri = $href_matches[1];
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}
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preg_match('/\stype=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $type_matches);
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if ( isset($type_matches[3]) ) {
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$link_type = $type_matches[3];
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} else if ( isset($type_matches[1]) ) {
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$link_type = $type_matches[1];
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}
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$links[] = array(
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'href' => $link_url,
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'rel' => $link_rel,
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'type' => $link_type,
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);
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}
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return $links;
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}
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}
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