magog2rss.php

<?php

/**
 * MaGog to RSS script for game update notifications.
 *
 * A script to scrape results from the
 * {@link [http://www.an-ovel.com/pages/magog.php] [<MaGog GOG search engine>]} and convert them
 * into an RSS feed.
 *
 * @author Kiran Welle
 */

/**
 * Specify the MaGog snapshot GUID to use.
 */
if( $_REQUEST['snap'] !== null ) {
    $MAGOG_SNAPSHOT = $_REQUEST['snap'];
} else {
    die("Please specify a MaGog snapshot to check.");
}

/**
 * Show games updated within this time period.
 */
$DAYS_SINCE_UPDATE = 1;

/**
 * Replace special characters to clean up the game titles.
 */
function clean_game_title( $title ) {
    $title = str_replace("®", "&#169;", htmlspecialchars($title));
    return mb_convert_encoding( $title, "UTF-8" );
}

/*
function guid_from_url( $url ) {
    $guid = split("/",$url);
    return $guid[count($guid)-1];
}
*/

/**
 * Encase the game description in a CDATA block to keep feed readers from complaining.
 */
function clean_description( $description ) {
    $innerHTML= '';
    foreach ($description->childNodes as $child) {
        $innerHTML .= $child->ownerDocument->saveXML( $child );
    }
    return "<![CDATA[".$innerHTML."]]>";
}

/**
 * Clean things up for the XML import. This should probably be replaced by JSON at some point.
 */
function clean_xml_document( $xml ) {
    $p = $xml->getElementsByTagName('p');
    if( $p->length > 0 )
        foreach( $p as $node ) {
            if( $node->getAttribute('class') == "nogames" )
                return false;
        }

    $table = $xml->getElementsByTagName('span');
    foreach($table as $node) {
        if( $node->getAttribute("class") == "dl_match" ) {
            $node->setAttribute("style","font-weight: bold; color: red;");
            $node->removeAttribute("class");

            $parent = $node->parentNode;
            if( $parent->tagName == "small" ) {
                if( $node->nextSibling->nodeName == "#text" && $node->nextSibling->nodeValue == "; " )
                    $parent->removeChild($node->nextSibling);
                $element = $xml->createElement('b');
                $para = $xml->createElement('p');
                $para->appendChild($element);
                $parent->replaceChild($para, $node);
                $element->appendChild($node);
            }
        }
    }
    $table = $xml->getElementsByTagName('tr');
    $table->item(0)->parentNode->removeChild($table->item(0));
    $table->item($table->length - 1)->parentNode->removeChild($table->item($table->length - 1));
    return $table;
}

/**
 * Format the MaGog URL and retrieve the results from MaGog.
 */
function setup_xml_document( &$url ) {
    global $DAYS_SINCE_UPDATE;
    if( $DAYS_SINCE_UPDATE > 0 )
        $date = date('dmY', strtotime('-'.$DAYS_SINCE_UPDATE.' days'));
    else
        $date = date('dmY');
    $url = preg_replace( '/flt=Dsa~([0-9]{8})/i', "flt=Dsa~$date", $url );

    // Create a new DOM Document to hold our webpage structure
    $xml = new DOMDocument();

    // Load the url's contents into the DOM
    if( $xml->loadHTMLFile($url) === false ) {
        http_response_code(404);
        die( "Retrieval of <b>$url<b> failed." );
    }

    return clean_xml_document($xml);
}

/**
 * Set up the headers for the file.
 */
function setup_headers() {
    header("Content-Type: application/rss+xml");
    echo '<?xml version="1.0" encoding="UTF-8" ?>'."\n";
    echo '<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">'."\n";
}

/**
 * Set up the meta data for the RSS feed.
 */
function get_channel( $url ) {
?>
    <channel>
        <title>GOG Game Updates via MaGog</title>
        <description>Recent game updates on GOG.com made available by MaGog.</description>
        <link><?php echo str_replace("&", "&amp;", $url) ?></link>
        <atom:link href="http://<?php echo $_SERVER[HTTP_HOST].$_SERVER[REQUEST_URI]; ?>" rel="self" type="application/rss+xml" />
<?php
}

/**
 * Retrieve and format a game.
 */
function get_item( $node ) {
?>
        <item>
            <title><?php echo clean_game_title($node->childNodes->item(1)->nodeValue) ?></title>
            <description><?php echo clean_description($node->nextSibling->firstChild); ?></description>
            <link><?php echo $node->childNodes->item(1)->firstChild->getAttribute("href"); ?></link>
            <guid><?php echo $node->childNodes->item(1)->firstChild->getAttribute("href"); ?></guid>
        </item>
<?php
}

/**
 * Run the thing. Maybe this will all become a class at some point?
 */
    $url = 'http://www.an-ovel.com/cgi-bin/magog.cgi?ver=422&scp=gdsp&dsp=fD&ord=&flt=Dsa~01012000~3an~owned%2C~&opt=d&myf='.$MAGOG_SNAPSHOT;
    $table = setup_xml_document($url);
    setup_headers();
    get_channel($url);

    if( $table !== false ) {
        $i = 0;
        foreach($table as $node) {
            $i++;
            if( $i % 2 == 0 ) continue;
            get_item( $node );
        }
    }
?>
    </channel>
</rss>