forked from GNUsocial/gnu-social
		
	
		
			
				
	
	
		
			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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