Self-hosting a podcast server

<?php
/*
    @license    http://www.gnu.org/licenses/agpl.txt
    @copyright  2014 Sourcefabric o.p.s.
    @link       http://www.sourcefabric.org
    @author     Micz Flor <micz.flor@sourcefabric.org>

    This php script will create a podcast XML on the fly
    listing all mp3/m4a files in the same directory.
*/

$channeltitle   = "Favorite Podcasts (No Ads)";
$channelauthor  = "Cool Pods w/o bad products";
/* $sortby sets the order in which tracks are listed.
   Options:
   "newest" = newest on top
   "oldest" = oldest on top
   "filedesc" = alphabetically descending
   "fileasc" = alphabetically ascending
   default: "filedesc" (== how streamplan.sh works)
*/
$sortby = "filedesc";

$dir = "https://" . $_SERVER['SERVER_NAME'];
$parts = explode('/', $_SERVER['REQUEST_URI']);
for ($i = 0; $i < count($parts) - 1; $i++) {
    $dir .= $parts[$i] . "/";
}

header('Content-type: text/xml', true);
echo "<?xml version='1.0' encoding='UTF-8'?>\n";
echo "<rss xmlns:itunes='http://www.itunes.com/DTDs/Podcast-1.0.dtd' version='2.0'>\n";
echo "<channel>\n";
echo "  <title>" . htmlspecialchars($channeltitle, ENT_XML1, 'UTF-8') . "</title>\n";
echo "  <link>$dir</link>\n";
echo "  <description>Favorite Podcasts</description>\n";
echo "  <itunes:image href='https://path.com/to/cover.png'/>\n";
echo "  <itunes:author>" . htmlspecialchars($channelauthor, ENT_XML1, 'UTF-8') . "</itunes:author>\n";
echo "  <language>en-us</language>\n";

// Read all mp3 and m4a files in the directory
$mp3files = glob("*.{mp3,m4a}", GLOB_BRACE);

// Create an array with timestamp.filename as key
$fileArray = [];
foreach ($mp3files as $filename) {
    $fileArray[filemtime($filename) . $filename] = $filename;
}

// Change the order of the list according to $sortby set above
switch ($sortby) {
    case "newest":
        krsort($fileArray);
        break;
    case "oldest":
        ksort($fileArray);
        break;
    case "fileasc":
        natcasesort($fileArray);
        break;
    default:
        // filedesc
        natcasesort($fileArray);
        $fileArray = array_reverse($fileArray);
        break;
}

// Function to get metadata using ffprobe
function getMetadata($file) {
    $command = "ffprobe -v quiet -print_format json -show_format -show_streams \"$file\"";
    $output = shell_exec($command);
    $metadata = json_decode($output, true);

    $title = $metadata['format']['tags']['title'] ?? pathinfo($file, PATHINFO_FILENAME);
    $artist = $metadata['format']['tags']['artist'] ?? 'Unknown Artist';
    $duration = $metadata['format']['duration'] ?? '0';

    // Remove everything after the first "|"
    if (strpos($title, '|') !== false) {
        $title = trim(explode('|', $title)[0]);
    }

    return [
        'title' => htmlspecialchars($title, ENT_XML1, 'UTF-8'),
        'artist' => htmlspecialchars($artist, ENT_XML1, 'UTF-8'),
        'duration' => gmdate("H:i:s", $duration),
    ];
}

// Go through files and create <item> for podcast
foreach ($fileArray as $filename) {
    $metadata = getMetadata($filename);

    // Properly encode filename for URL
    $fileUrl = $dir . str_replace(' ', '%20', urlencode($filename));
    $filesize = filesize($filename);

    // Format title as "title (artist)"
    $formattedTitle = "{$metadata['title']} ({$metadata['artist']})";

    echo "  <item>\n";
    echo "    <title>" . htmlspecialchars($formattedTitle, ENT_XML1, 'UTF-8') . "</title>\n";
    echo "    <itunes:subtitle>" . htmlspecialchars($formattedTitle, ENT_XML1, 'UTF-8') . "</itunes:subtitle>\n";
    echo "    <enclosure url=\"$fileUrl\" length=\"$filesize\" type=\"audio/mpeg\"/>\n";
    echo "    <itunes:duration>{$metadata['duration']}</itunes:duration>\n";
    echo "    <guid>$fileUrl</guid>\n";
    echo "    <pubDate>" . date("r", filemtime($filename)) . "</pubDate>\n";
    echo "  </item>\n";
}

echo "</channel>\n";
echo "</rss>\n";
?>