Simple PHP script for generating RSS feeds from Bluesky user posts

bluesky-rss-feed.php

<?php

# USAGE: 
# https://your.domain/path/to/script?h=[some bluesky handle]
# https://your.domain/path/to/script?h=[some bluesky handle]&reply=exclude

# CONFIG
define('BSKY_HANDLE', '<your full bluesky handle>');
define('BSKY_APP_PASSWORD', '<your bluesky app password>');

define('BSKY_PDS_URL', 'https://bsky.social');
define('MAX_POSTS', 20);
define('BSKY_SESSION_FILE', '../session.json');  # web server must have write permission for this location

if (!isset($_GET['h']))
{
    http_response_code(400);
    $url = $_SERVER['REQUEST_SCHEME'] . '://' . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI'];
    die("Usage:<br>$url?h=[some-blueky-handle]<br>$url?h=[some-blueky-handle]&reply=exclude");
}

function login()
{
    $url = BSKY_PDS_URL . '/xrpc/com.atproto.server.createSession';
    $postdata = json_encode([
        'identifier' => BSKY_HANDLE,
        'password' => BSKY_APP_PASSWORD,
    ]);
    $res = file_get_contents(
        $url,
        false,
        stream_context_create([
            'http' => [
                'method' => 'POST',
                'header' => "Content-Type: application/json\r\n",
                'content' => $postdata,
                'ignore_errors' => true,
            ]
        ])
    );
    $session = json_decode($res, true);
    if (isset($session['accessJwt']))
        file_put_contents(BSKY_SESSION_FILE, $res);
    return $session;
}

function refresh_session($refreshJwt)
{
    $url = BSKY_PDS_URL . '/xrpc/com.atproto.server.refreshSession';
    $res = file_get_contents(
        $url,
        false,
        stream_context_create([
            'http' => [
                'method' => 'POST',
                'header' => "Content-Type: application/json\r\n" .
                    'Authorization: Bearer ' . $refreshJwt . "\r\n",
                'ignore_errors' => true,
            ]
        ])
    );
    $session = json_decode($res, true);
    if (isset($session['accessJwt']))
        file_put_contents(BSKY_SESSION_FILE, $res);
    return $session;
}

function get_feed($author, $filter, $accessJwt)
{
    $res = file_get_contents(
        BSKY_PDS_URL . '/xrpc/app.bsky.feed.getAuthorFeed?actor=' . $author . '&limit=' . MAX_POSTS . $filter,
        false,
        stream_context_create([
            'http' => [
                'method' => 'GET',
                'header' => 'Authorization: Bearer ' . $accessJwt . "\r\n",
                'ignore_errors' => true,
            ]
        ])
    );
    return [json_decode($res, true), $http_response_header];
}

$author = $_GET['h'];
$filter = @$_GET['reply'] == 'exclude' ? '&filter=posts_no_replies' : '';

########################################
# If there is a session stored, first try if its accessJwt is still valid.
# If not, try to refresh the session using the refreshJwt.
# IF that also fails, login and try again.
########################################

$session = json_decode(@file_get_contents(BSKY_SESSION_FILE), true);
if (isset($session['accessJwt']))
{
    list($data, $response_header) = get_feed($author, $filter, $session['accessJwt']);
    if (isset($data['error']))
    {
        $session = refresh_session($session['refreshJwt']);
        if (isset($session['error']))
            $session = login();
        list($data, $response_header) = get_feed($author, $filter, $session['accessJwt']);
    }
}
else
{
    $session = login();
    list($data, $response_header) = get_feed($author, $filter, $session['accessJwt']);
}

if (isset($data['error']))
{
    preg_match('{HTTP\/\S*\s(\d{3})}', $response_header[0], $match);
    http_response_code((int)$match[1]);
    die($data['message']);
}

$atom_url = htmlspecialchars($_SERVER['REQUEST_SCHEME'] . '://' . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI']);

header('Content-Type: text/xml; charset=UTF-8');

echo '<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
    xmlns:atom="http://www.w3.org/2005/Atom"
    xmlns:dc="http://purl.org/dc/elements/1.1/">
    <channel>
        <title>' . $author . ' Feed</title>
        <atom:link href="' . $atom_url . '" rel="self" type="application/rss+xml" />
        <link>' . $atom_url . '</link>
        <description>' . $author . '\'s posts in https://bsky.social</description>
';

foreach ($data['feed'] as $item)
{
    $date = date('r', strtotime($item['post']['record']['createdAt']));
    $link = 'https://bsky.app/profile/' . str_replace('app.bsky.feed.', '', substr($item['post']['uri'], 5));
?>
        <item>
            <title><?php echo htmlspecialchars($item['post']['record']['text']); ?></title>
            <description><![CDATA[<p><?php echo htmlspecialchars($item['post']['record']['text']); ?></p>
<?php
    if (isset($item['post']['embed']['images']))
    {
        foreach ($item['post']['embed']['images'] as $image)
        {
?>
                <figure>
                    <a href="<?php echo $image['fullsize']; ?>"><img src="<?php echo $image['thumb']; ?>" alt="<?php echo htmlspecialchars(@$image['alt']); ?>" /></a>
                </figure>
<?php
        }
    }
?>
            ]]></description>
            <link><?php echo  $link; ?></link>
            <guid isPermaLink="false"><?php echo $item['post']['uri']; ?></guid>
            <pubDate><?php echo $date; ?></pubDate>
            <dc:creator><?php echo $author; ?></dc:creator>
        </item>
<?php
}
?>
    </channel>
</rss>