outbox.php

<?php

/**
 * This is the Outbox for a user.
 *
 * Outbox is required by the ActivityPub spec, but most servers do not
 * actually care about this (it's used mainly for client-to-server posting).
 *
 * However, it COULD be used by a server wanting to replay missed events
 * in case of connection errors or new federation, to populate a cache on
 * the new instance.
 *
 * We return a list of events, in reverse chronological order, filtered by
 * the user.
 */

include_once 'admin/functions.php';

// Required parameters: user
if (! empty($_GET['user'])) {
  // instance actor - always return an empty collection
    if (strtolower($_GET['user']) === $_SERVER['SERVER_NAME']) {
        $outbox = [];
    } else {
      // TODO: Validate request signature

        $db = new SQLite3("admin/db.sqlite3", SQLITE3_OPEN_READONLY);
        $result = query($db, 'SELECT id, content FROM post WHERE user=? ORDER BY id DESC', $_GET['user']);
        $db->close();

        if (count($result) > 0) {
          // push each activity into the orderedItems
            foreach ($result as $a) {
                // recreate the original activity from the db bits
                $activity = [
                'id' => $phpActivityPub_root . 'activity.php?create=1&id=' . $a['id'],
                'type' => 'Create',
                'actor' => $phpActivityPub_root . 'actor.php?user=' . $_GET['user'],
                "to" => 'https://www.w3.org/ns/activitystreams#Public',
                'content' => array_merge([
                "id" => $phpActivityPub_root . 'activity.php?id=' . $a['id'],
                "type" => 'Note',
                "attributedTo" => $phpActivityPub_root . 'actor.php?user=' . $_GET['user'],
                "to" => 'https://www.w3.org/ns/activitystreams#Public'
                ], json_decode($a['content'], true))
                ];

                $outbox[] = $activity;
            }
        } else {
            response(404, [ 'error' => 'Invalid user in outbox request' ]);
        }
    }

    response(200, [
    '@context' => 'https://www.w3.org/ns/activitystreams',
    'type' => 'OrderedCollection',
    'totalItems' => count($outbox),
    'orderedItems' => $outbox
    ]);
} else {
    response(400, [ 'error' => 'User missing from outbox request' ]);
}