class.ilExternalFeed.php

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<?php
/* Copyright (c) 1998-2009 ILIAS open source, Extended GPL, see docs/LICENSE */

require_once 'classes/class.ilProxySettings.php';

define("MAGPIE_DIR", "./Services/Feeds/magpierss/");
define("MAGPIE_CACHE_ON", true);
define("MAGPIE_CACHE_DIR", "./".ILIAS_WEB_DIR."/".CLIENT_ID."/magpie_cache");
define('MAGPIE_OUTPUT_ENCODING', "UTF-8");
define('MAGPIE_CACHE_AGE', 900);                        // 900 seconds = 15 minutes
include_once(MAGPIE_DIR."/rss_fetch.inc");

include_once("./Services/Feeds/classes/class.ilExternalFeedItem.php");

class ilExternalFeed
{
        protected $items = array();
        
        function ilExternalFeed()
        {               
                // IF YOU ADD THINGS HERE, THEY MAY ALSO BE ADDED TO
                // SOME OF THE STATIC METHODS
                $this->_createCacheDirectory();

                if(ilProxySettings::_getInstance()->isActive())
                {
                        define('IL_FEED_PROXY_HOST', ilProxySettings::_getInstance()->getHost());
                        define('IL_FEED_PROXY_PORT', ilProxySettings::_getInstance()->getPort());
                }
                else
                {
                        define('IL_FEED_PROXY_HOST', "");
                        define('IL_FEED_PROXY_PORT', "");
                }
        }

        function setUrl($a_url)
        {
                $this->url = $a_url;
        }

        function getUrl()
        {
                return $this->url;
        }

        function setError($a_error)
        {
                $this->error = $a_error;
        }

        function getError()
        {
                return $this->error;
        }

        static function _createCacheDirectory()
        {
                if (!is_dir(ilUtil::getWebspaceDir()."/magpie_cache"))
                {
                        ilUtil::makeDir(ilUtil::getWebspaceDir()."/magpie_cache");
                }
        }
        
        static function _checkUrl($a_url)
        {
                if (!defined('IL_FEED_PROXY_HOST'))
                {                       
                        ilExternalFeed::_createCacheDirectory();

                        if(ilProxySettings::_getInstance()->isActive())
                        {
                                define('IL_FEED_PROXY_HOST', ilProxySettings::_getInstance()->getHost());
                                define('IL_FEED_PROXY_PORT', ilProxySettings::_getInstance()->getPort());
                        }
                        else
                        {
                                define('IL_FEED_PROXY_HOST', "");
                                define('IL_FEED_PROXY_PORT', "");
                        }
                }
                
                $feed = @fetch_rss($a_url);
                if (!$feed)
                {
                        $error = magpie_error();
                        
                        if ($error != "")
                        {
                                return $error;
                        }
                        else
                        {
                                return "Unknown Error.";
                        }
                }
                
                return true;
        }
        
        function fetch()
        {
                if ($this->getUrl() != "")
                {
                        $this->feed = @fetch_rss($this->getUrl());
                }
                
                if(!$this->feed)
                {
                        $error = magpie_error();
                        if ($error == "")
                        {
                                $this->setError("Unknown Error.");
                        }
                        else
                        {
                                $this->setError(magpie_error());
                        }
                        return false;
                }
                
                if (is_array($this->feed->items))
                {
                        foreach($this->feed->items as $item)
                        {
                                $item_obj = new ilExternalFeedItem();
                                $item_obj->setMagpieItem($item);
                                $this->items[] = $item_obj;
                        }
                }
        }
        
        function checkCacheHit()
        {
                ilExternalFeed::_createCacheDirectory();
                
                $cache = new RSSCache( MAGPIE_CACHE_DIR, MAGPIE_CACHE_AGE );
        
        $cache_status    = 0;       // response of check_cache
        $request_headers = array(); // HTTP headers to send with fetch
        $rss             = 0;       // parsed RSS object
        $errormsg        = 0;       // errors, if any
        
        $cache_key       = $this->getUrl().MAGPIE_OUTPUT_ENCODING;
        
        if (!$cache->ERROR) {
            // return cache HIT, MISS, or STALE
            $cache_status = $cache->check_cache( $cache_key);
        }
                
        // if object cached, and cache is fresh, return cached obj
        if ($cache_status == 'HIT')
                {
                        return true;
                }
                
                return false;
        }
        
        function getChannelTitle()
        {
                return $this->feed->channel["title"];
        }

        function getChannelDescription()
        {
                return $this->feed->channel["description"];
        }

        function getItems()
        {
                return $this->items;
        }
        
        static function _determineFeedUrl($a_url)
        {
                if (!defined('IL_FEED_PROXY_HOST'))
                {
                        if(ilProxySettings::_getInstance()->isActive())
                        {
                                define('IL_FEED_PROXY_HOST', ilProxySettings::_getInstance()->getHost());
                                define('IL_FEED_PROXY_PORT', ilProxySettings::_getInstance()->getPort());
                        }
                        else
                        {
                                define('IL_FEED_PROXY_HOST', "");
                                define('IL_FEED_PROXY_PORT', "");
                        }
                }

                $res = @fopen($a_url, "r");
                
                if (!$res)
                {
                        return "";
                }
                
                $contents = '';
                while (!feof($res))
                {
                        $contents.= fread($res, 8192);
                }
                fclose($res);
                
                return ilExternalFeed::_getRSSLocation($contents, $a_url);
        }
        
        function _getRSSLocation($html, $location)
        {
                if(!$html or !$location){
                        return false;
                }else{
                        #search through the HTML, save all <link> tags
                        # and store each link's attributes in an associative array
                        preg_match_all('/<link\s+(.*?)\s*\/?>/si', $html, $matches);
                        $links = $matches[1];
                        $final_links = array();
                        $link_count = count($links);
                        for($n=0; $n<$link_count; $n++){
                                $attributes = preg_split('/\s+/s', $links[$n]);
                                foreach($attributes as $attribute){
                                        $att = preg_split('/\s*=\s*/s', $attribute, 2);
                                        if(isset($att[1])){
                                                $att[1] = preg_replace('/([\'"]?)(.*)\1/', '$2', $att[1]);
                                                $final_link[strtolower($att[0])] = $att[1];
                                        }
                                }
                                $final_links[$n] = $final_link;
                        }
                        #now figure out which one points to the RSS file
                        for($n=0; $n<$link_count; $n++){
                                if(strtolower($final_links[$n]['rel']) == 'alternate'){
                                        if(strtolower($final_links[$n]['type']) == 'application/rss+xml'){
                                                $href = $final_links[$n]['href'];
                                        }
                                        if(!$href and strtolower($final_links[$n]['type']) == 'text/xml'){
                                                #kludge to make the first version of this still work
                                                $href = $final_links[$n]['href'];
                                        }
                                        if($href){
                                                if(strstr($href, "http://") !== false){ #if it's absolute
                                                        $full_url = $href;
                                                }else{ #otherwise, 'absolutize' it
                                                        $url_parts = parse_url($location);
                                                        #only made it work for http:// links. Any problem with this?
                                                        $full_url = "http://$url_parts[host]";
                                                        if(isset($url_parts['port'])){
                                                                $full_url .= ":$url_parts[port]";
                                                        }
                                                        if($href{0} != '/'){ #it's a relative link on the domain
                                                                $full_url .= dirname($url_parts['path']);
                                                                if(substr($full_url, -1) != '/'){
                                                                        #if the last character isn't a '/', add it
                                                                        $full_url .= '/';
                                                                }
                                                        }
                                                        $full_url .= $href;
                                                }
                                                return $full_url;
                                        }
                                }
                        }
                        return false;
                }
        }
}
?>