Interactive browser for a Docker Registry API (v2)

docker_registry_browser.php

<?php
/**
 * Browse a specified (v2) Docker Registry, examine layers, extract useful data >.>
 **/
ini_set('error_reporting', E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED & ~E_WARNING);

$headers = [];

$type = isset($_GET['type']) ? $_GET['type'] : '_catalog';
$registry = (isset($_GET['registry'])) ? $_GET['registry'] : '';
$tag = isset($_GET['tag']) ? $_GET['tag'] : '';
$repo = isset($_GET['repo']) ? $_GET['repo'] : '';

if(!$registry) {
    echo "registry query param is required";
    die;
}

$delete = $digestsLink = '';
$pre = true;

if($type === '_catalog') {
    $url = "/$type?n=1000";
}
elseif($type === 'repo') {
    $url = "/$repo/tags/list";
}
elseif($type === 'tag') {
    $url = "/$repo/manifests/$tag";
}
elseif($type === 'tagdigests') {
    $url = "/$repo/manifests/$tag";
    $headers[] = 'Accept: application/vnd.docker.distribution.manifest.v2+json';
}
elseif($type === 'blob') {
    $digest = $_GET['digest'];
    $url = "/$repo/blobs/$digest";
    $headers[] = 'Range: bytes=0-4096';
}

if(isset($_SERVER['PHP_AUTH_USER'])) {
    $auth = base64_encode($_SERVER['PHP_AUTH_USER'] . ':' . $_SERVER['PHP_AUTH_PW']);
    $headers[] = "Authorization: Basic $auth";
}

//DELETE a TAG
// DELETE /v2/<name>/manifests/<reference>

$host = "https://$registry/v2";
$context = stream_context_create(
    [
        'http' => [
            'method' => $_SERVER['REQUEST_METHOD'],
            'header' => implode("\r\n", $headers),
        ],
    ]
);
$data = file_get_contents($host . $url, false, $context);

header($http_response_header[0]);
if($http_response_header[0] === 'HTTP/1.1 401 Unauthorized') {
    header('WWW-Authenticate: Basic realm="User Visible Realm"');
    return;
}

if($_SERVER['REQUEST_METHOD'] !== 'GET') {
    header('content-type: text/json');
    print_r($http_response_header);
    echo $url."\n";
    echo $data;
    exit;
};
header('content-type: text/html');

if($type !== 'blob') {
    $data = json_decode($data, 1);
}

if($type === '_catalog') {
    foreach($data['repositories'] as &$repo) {
        $repo = "<a href='?registry=$registry&amp;type=repo&amp;repo=$repo'>$repo</a>";
    }
}
elseif($type === 'repo') {
    usort(
        $data['tags'],
        function($a, $b) {
            return version_compare($a, $b);
        }
    );
    foreach($data['tags'] as &$tag) {
        $tag = "<a href='?registry=$registry&amp;type=tag&amp;repo=$repo&amp;tag=$tag'>$tag</a>";
    }
}
elseif($type === 'tag') {
    $digestsLink = "<a href='?registry=$registry&amp;type=tagdigests&amp;repo=$repo&amp;tag=$tag&amp;showdigests=1'>[see digests]</a>";
    foreach($data['history'] as &$hist) {
        $hist['v1Compatibility'] = json_decode($hist['v1Compatibility'], 1);
    }
    foreach($data['fsLayers'] as &$fsLayer) {
        $fsLayer['blobSum'] = "<a href='?registry=$registry&amp;type=blob&amp;repo=$repo&amp;digest={$fsLayer['blobSum']}'>{$fsLayer['blobSum']}</a>";
    }
}
elseif($type === 'tagdigests') {
    $href = "?registry=$registry&amp;type=tag&amp;repo=$repo&amp;tag=". urlencode($data['config']['digest']);
    $delete =  "<a class='delete' href='$href' data-tag='$tag'>[DELETE TAG]</a>";
}
elseif($type === 'blob') {
    $tempfile = tempnam('/tmp', 'blob');
    file_put_contents($tempfile, $data);
    $data = `/bin/cat $tempfile |gzip -d`;
    unlink($tempfile);
    $data = str_split($data, 72);
    $data = str_split($data, 72);
    $color = '#888';
    $placeholder = '.';
    $repl = function($m) use (&$color, &$placeholder) {
        $x = str_repeat($placeholder, strlen($m[0]));
        return '<span style="background-color:'.$color.';">'.$x.'</span>';
    };
    foreach($data as &$d) {
        $d = str_replace(['<','>'], ['&lt;','&gt;'], $d);
        $d = preg_replace_callback('/\x00+/', $repl, $d);
        $color = '#f88';
        $d = preg_replace_callback('/[\x01-\x0f]+/', $repl, $d);
        $color = '#aaf';
        $d = preg_replace_callback('/[\x10-\x1f]+/', $repl, $d);
        $color = '#fa0';
        $d = preg_replace_callback('/[\x7f-\xff]+/', $repl, $d);
        $color = '#ccc';
        $d = preg_replace_callback('/[^\x20-\x7f]+/', $repl, $d);
    }
    $data = implode('<br>', $data);
    $pre = false;
}

$prt = function($data, $depth=1) use (&$prt) {
    if(!is_array($data)) {
        return "'$data'";
    }
    $out = '{'. "\n";
    foreach($data as $k => $d) {
        $out .= str_repeat(' ', $depth*4) . "$k: " . $prt($d, $depth + 1) ."\n";
    }
    $out .= str_repeat(' ', ($depth-1)*4) . '}'. "\n";
    return $out;
};

?>
<!DOCTYPE html>
<html><head>
    <meta charset="UTF-8">
    <title>Interactive Docker Registry</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <script
        src="https://code.jquery.com/jquery-3.1.1.min.js"
        integrity="sha256-hVVnYaiADRTO2PzUGmuLJr8BLUSjGIZsDYGmIJLv2b8="
        crossorigin="anonymous"></script>
    <script lang="javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    <style>
        body { margin: 5px 50px; }
        a.delete { color: red; font-weight: bold; cursor: pointer; }
    </style>
    <script lang="javascript">
        $(window).on('load', function(){
            $('a.delete').on('click', function(e) {
                e.preventDefault();
                var link = $(this);
                var tag = link.attr('data-tag');
                var c = confirm("Are you sure you want to delete tag '" + tag + "' ?");
                if(!c) return false;
                $.ajax({
                    type: 'DELETE',
                    url: link.attr('href')
                }).done(function(e) {
                    window.location.reload();
                });
                return false;
            });
        });
    </script>
</head><body>
<div class="content">
    <h1><a href="?registry=<?= $registry ?>">Interactive Docker Registry</a></h1>
    <?= $delete ?>
    <?= $digestsLink ?>
    <pre>
<?= $prt($data) ?>
    </pre>
</div>
</body></html>