130 lines
3.8 KiB
PHP
130 lines
3.8 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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* Parse HTTP response for interesting Link: headers
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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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if (!defined('STATUSNET')) {
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exit(1);
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}
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/**
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* Class to represent Link: headers in an HTTP response
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*
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* Since these are a fairly important part of Hammer-stack discovery, they're
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* reified and implemented here.
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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 Discovery
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*/
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class LinkHeader
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{
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var $href;
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var $rel;
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var $type;
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/**
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* Initialize from a string
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*
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* @param string $str Link: header value
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*
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* @return LinkHeader self
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*/
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function __construct($str)
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{
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preg_match('/^<[^>]+>/', $str, $uri_reference);
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//if (empty($uri_reference)) return;
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$this->href = trim($uri_reference[0], '<>');
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$this->rel = array();
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$this->type = null;
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// remove uri-reference from header
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$str = substr($str, strlen($uri_reference[0]));
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// parse link-params
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$params = explode(';', $str);
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foreach ($params as $param) {
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if (empty($param)) {
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continue;
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}
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list($param_name, $param_value) = explode('=', $param, 2);
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$param_name = trim($param_name);
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$param_value = preg_replace('(^"|"$)', '', trim($param_value));
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// for now we only care about 'rel' and 'type' link params
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// TODO do something with the other links-params
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switch ($param_name) {
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case 'rel':
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$this->rel = trim($param_value);
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break;
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case 'type':
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$this->type = trim($param_value);
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}
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}
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}
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/**
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* Given an HTTP response, return the requested Link: header
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*
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* @param HTTP_Request2_Response $response response to check
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* @param string $rel relationship to look for
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* @param string $type media type to look for
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*
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* @return LinkHeader discovered header, or null on failure
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*/
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static function getLink($response, $rel=null, $type=null)
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{
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$headers = $response->getHeader('Link');
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if ($headers) {
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// Can get an array or string, so try to simplify the path
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if (!is_array($headers)) {
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$headers = array($headers);
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}
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foreach ($headers as $header) {
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$lh = new LinkHeader($header);
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if ((is_null($rel) || $lh->rel == $rel) &&
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(is_null($type) || $lh->type == $type)) {
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return $lh->href;
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}
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}
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}
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return null;
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}
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}
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