class.ilExternalFeed.php

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

require_once './Services/Http/classes/class.ilProxySettings.php';

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

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

class ilExternalFeed
{
    protected $items = array();
    
    public function __construct()
    {
        // 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', "");
        }
    }

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

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

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

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

    public static function _createCacheDirectory()
    {
        if (!is_dir(ilUtil::getDataDir() . "/magpie_cache")) {
            ilUtil::makeDir(ilUtil::getDataDir() . "/magpie_cache");
        }
    }
    
    public 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;
    }
    
    public 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;
            }
        }
    }
    
    public 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;
    }
    
    public function getChannelTitle()
    {
        return $this->feed->channel["title"];
    }

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

    public function getItems()
    {
        return $this->items;
    }
    
    public 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);
    }
    
    public static 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;
        }
    }
}