RSS フィードから必要の無い記事を様々な条件でフィルタリングして再配信させるコード

<?php
$feedUrl = 'http://example.com/feed';
$feedTitle = 'Sample feed';
$feedDescription = 'This is a sample feed.';
$rss = simplexml_load_file($feedUrl);
$rss = get_object_vars($rss);
foreach($rss['item'] as $key => $item) {
    if(preg_match('/iPhone/', $item->title)) unset($rss['item'][$key]);
}
?>
<?php echo '<?xml version="1.0" encoding="UTF-8"?>'; ?>
<rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/">
<channel>
    <title><?php echo $feedTitle; ?></title>
    <link><?php echo $feedUrl; ?></link>
    <description><?php echo $feedDescription; ?></description>
    <language>ja</language>
    <pubDate><?php echo date(DATE_RFC822); ?></pubDate>
    <lastBuildDate><?php echo date(DATE_RFC822); ?></lastBuildDate>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <?php foreach($rss['item'] as $item): ?>
    <item>
        <title><?php echo $item->title; ?></title>
        <link><?php echo $item->link; ?></link>
        <description><?php echo $item->description; ?></description>
        <content:encoded><![CDATA[<?php echo $item->description; ?>]]></content:encoded>
        <pubDate><?php echo date('D, d M Y H:i:s O'); ?></pubDate>
    </item>
    <?php endforeach; ?>
</channel>
</rss>