add webring to main site

ring/index.php

@@ -0,0 +1,68 @@
+<?php
+$filepath = __FILE__;
+$action = $_GET["action"] ?? "index";
+$users = array_map(function ($f) { return basename(dirname($f)); }, glob("/home/*/.ring"));
+
+if ($action !== "index") {
+    // handle webring redirects
+    $me = $_GET["me"] ?? "";
+    $i = array_search($me, $users) ?? 0;
+
+    switch ($action) {
+    case "random":
+        $notme = array_diff($users, [$me]);
+        $user = $notme[array_rand($notme)];
+        break;
+    case "next":
+        $user = $users[$i + 1] ?? reset($users);
+        break;
+    case "prev":
+        $user = $users[$i - 1] ?? end($users);
+        break;
+    default:
+        die("invalid action");
+    }
+
+    header("Location: https://tilde.team/~$user/");
+    die();
+}
+else {
+    // keep this as a string so we can escape it easily with htmlspecialchars()
+    $snippet = '<!-- tilde.team ring fragment-->
+<div id="newring">
+<center>
+[<a href="https://tilde.team/ring/?action=prev&me=USERNAME">previous</a>]
+[<a href="https://tilde.team/ring/?action=random&me=USERNAME">random</a>]
+[<a href="https://tilde.team/ring/?action=next&me=USERNAME">next</a>]
+<br>
+<a href="https://tilde.team/ring/">how to join this webring</a>
+</center>
+</div>';
+
+    include __DIR__ . '/../header.php';
+?>
+    <h1>how to join the webring</h1>
+
+    <p>this webring can be joined by any user on tilde.team.</p>
+    <p>first, add the following links to your page, replacing USERNAME by your username (no ~):</p>
+
+    <pre><?=htmlspecialchars($snippet)?></pre>
+
+    <p>you may edit the code however you want. it should work as long as the URLs are kept in place and have your user in them.</p>
+
+    <p>then create a .ring file in your ~ to be added in the webring:</p>
+    <pre>$ touch ~/.ring</pre>
+
+    <h3>explore webring</h3>
+    <p><a href="?action=random">jump to random page</a></p>
+    <p>all members:</p>
+    <ul>
+    <?php foreach ($users as $user): ?>
+        <li><a href="https://tilde.team/~<?=$user?>/">~<?=$user?></a></li>
+    <?php endforeach; ?>
+    </ul>
+
+    <p>it will probably work if you copy it to your own <code>~/public_html</code> and adjust the links accordingly.</p>
+<?php 
+    include __DIR__ . '/../footer.php';
+}