streams/Code/Module/Activity.php

<?php

namespace Code\Module;

use Code\Lib\IConfig;
use Code\Web\Controller;
use Code\Lib\ActivityStreams;
use Code\Lib\Activity as ZlibActivity;
use Code\Lib\Libzot;
use Code\Web\HTTPSig;
use Code\Lib\LDSignatures;
use Code\Lib\ThreadListener;
use Code\Lib\Channel;
use App;

class Activity extends Controller
{

    public function init()
    {


        if (ActivityStreams::is_as_request()) {
            $item_id = argv(1);

            if (!$item_id) {
                return;
            }
            $portable_id = false;
            $ob_authorise = false;
            $token = false;

            $bear = ZlibActivity::token_from_request();
            if ($bear) {
                logger('bear: ' . $bear, LOGGER_DEBUG);
                $t = q(
                    "select item.uid, iconfig.v from iconfig left join item on iid = item.id where cat = 'ocap' and item.uuid = '%s'",
                    dbesc($item_id)
                );
                if ($t) {
                    foreach ($t as $token) {
                        if ($token['v'] === $bear) {
                            $ob_authorise = true;
                            break;
                        }
                    }
                }
            }

            $item_normal = " and item.item_hidden = 0 and item.item_type = 0 and item.item_unpublished = 0 
				and item.item_delayed = 0 and item.item_blocked = 0 ";

            $sigdata = HTTPSig::verify(EMPTY_STR);
            if ($sigdata['portable_id'] && $sigdata['header_valid']) {
                $portable_id = $sigdata['portable_id'];
                if (!check_channelallowed($portable_id)) {
                    http_status_exit(403, 'Permission denied');
                }
                if (!check_siteallowed($sigdata['signer'])) {
                    http_status_exit(403, 'Permission denied');
                }
                observer_auth($portable_id);
            }

            // if passed an owner_id of 0 to item_permissions_sql(), we force "guest access" or observer checking
            // Give ocap tokens priority

            if ($ob_authorise) {
                $sql_extra = " and item.uid = " . intval($token['uid']) . " ";
            } else {
                $sql_extra = item_permissions_sql(0);
            }

            $r = q(
                "select * from item where ( uuid = '%s' or mid = '%s' or mid = '%s' ) $item_normal $sql_extra limit 1",
                dbesc($item_id),
                dbesc(z_root() . '/activity/' . $item_id),
                dbesc(z_root() . '/item/' . $item_id)
            );
 /*           // Check aliases (wip)
            if (!$r) {
                $alias = q("select * from iconfig where cat = 'system' and k = 'alsoKnownAs' and v in ('%s', '%s')",
                    dbesc(z_root() . '/activity/' . $item_id),
                    dbesc(z_root() . '/item/' . $item_id)
                );
                if ($alias) {
                    $r = q("select * from item where id = %d $item_normal $sql_extra limit 1",
                        intval($alias[0]['iid'])
                    );
                }
            }
*/
            if (!$r) {
                $r = q(
                    "select * from item where ( uuid = '%s' or mid = '%s' or mid = '%s' ) $item_normal limit 1",
                    dbesc($item_id),
                    dbesc(z_root() . '/activity/' . $item_id),
                    dbesc(z_root() . '/item/' . $item_id)
                );

                if ($r) {
                    http_status_exit(403, 'Forbidden');
                }
                http_status_exit(404, 'Not found');
            }

            xchan_query($r, true);
            $items = fetch_post_tags($r);

            if ($portable_id && (!intval($items[0]['item_private']))) {
                $c = q(
                    "select abook_id from abook where abook_channel = %d and abook_xchan = '%s'",
                    intval($items[0]['uid']),
                    dbesc($portable_id)
                );
                if (!$c) {
                    ThreadListener::store(z_root() . '/activity/' . $item_id, $portable_id);
                }
            }

            $channel = Channel::from_id($items[0]['uid']);

            as_return_and_die(ZlibActivity::encode_activity($items[0], true), $channel);
        }

        if (Libzot::is_nomad_request()) {
            $item_id = argv(1);

            if (!$item_id) {
                http_status_exit(404, 'Not found');
            }

            $portable_id = EMPTY_STR;

            $item_normal = " and item.item_hidden = 0 and item.item_type = 0 and item.item_unpublished = 0 and item.item_delayed = 0 and item.item_blocked = 0 and not verb in ( 'Follow', 'Ignore' ) ";

            $i = null;

            // do we have the item (at all)?

            $r = q(
                "select * from item where mid = '%s' $item_normal limit 1",
                dbesc(z_root() . '/activity/' . $item_id)
            );

            if (!$r) {
                $r = q(
                    "select * from item where mid = '%s' $item_normal limit 1",
                    dbesc(z_root() . '/item/' . $item_id)
                );
                if ($r) {
                    goaway(z_root() . '/item/' . $item_id);
                }
                http_status_exit(404, 'Not found');
            }

            // process an authenticated fetch

            $sigdata = HTTPSig::verify(EMPTY_STR);
            if ($sigdata['portable_id'] && $sigdata['header_valid']) {
                $portable_id = $sigdata['portable_id'];
                observer_auth($portable_id);

                // first see if we have a copy of this item's parent owned by the current signer
                // include xchans for all zot-like networks - these will have the same guid and public key

                $x = q(
                    "select * from xchan where xchan_hash = '%s'",
                    dbesc($sigdata['portable_id'])
                );

                if ($x) {
                    $xchans = q(
                        "select xchan_hash from xchan where xchan_hash = '%s' OR ( xchan_guid = '%s' AND xchan_pubkey = '%s' ) ",
                        dbesc($sigdata['portable_id']),
                        dbesc($x[0]['xchan_guid']),
                        dbesc($x[0]['xchan_pubkey'])
                    );

                    if ($xchans) {
                        $hashes = ids_to_querystr($xchans, 'xchan_hash', true);
                        $i = q(
                            "select id as item_id from item where mid = '%s' $item_normal and owner_xchan in ( " . protect_sprintf($hashes) . " ) limit 1",
                            dbesc($r[0]['parent_mid'])
                        );
                    }
                }
            }

            // if we don't have a parent id belonging to the signer see if we can obtain one as a visitor that we have permission to access
            // with a bias towards those items owned by channels on this site (item_wall = 1)

            $sql_extra = item_permissions_sql(0);

            if (!$i) {
                $i = q(
                    "select id as item_id from item where mid = '%s' $item_normal $sql_extra order by item_wall desc limit 1",
                    dbesc($r[0]['parent_mid'])
                );
            }

            $bear = ZlibActivity::token_from_request();
            if ($bear) {
                logger('bear: ' . $bear, LOGGER_DEBUG);
                if (!$i) {
                    $t = q(
                        "select * from iconfig where cat = 'ocap' and k = 'relay' and v = '%s'",
                        dbesc($bear)
                    );
                    if ($t) {
                        $i = q(
                            "select id as item_id from item where uuid = '%s' and id = %d $item_normal limit 1",
                            dbesc($item_id),
                            intval($t[0]['iid'])
                        );
                    }
                }
            }


            if (!$i) {
                http_status_exit(403, 'Forbidden');
            }

            $parents_str = ids_to_querystr($i, 'item_id');

            $items = q(
                "SELECT item.*, item.id AS item_id FROM item WHERE item.parent IN ( %s ) $item_normal ",
                dbesc($parents_str)
            );

            if (!$items) {
                http_status_exit(404, 'Not found');
            }

            xchan_query($items, true);
            $items = fetch_post_tags($items);

            $observer = App::get_observer();
            $parent = $items[0];
            $recips = (($parent['owner']['xchan_network'] === 'activitypub') ? get_iconfig($parent['id'], 'activitypub', 'recips', []) : []);
            $to = (($recips && array_key_exists('to', $recips) && is_array($recips['to'])) ? $recips['to'] : null);
            $nitems = [];
            foreach ($items as $i) {
                $mids = [];

                if (intval($i['item_private'])) {
                    if (!$observer) {
                        continue;
                    }
                    // ignore private reshare, possibly from hubzilla
                    if ($i['verb'] === 'Announce') {
                        if (!in_array($i['thr_parent'], $mids)) {
                            $mids[] = $i['thr_parent'];
                        }
                        continue;
                    }
                    // also ignore any children of the private reshares
                    if (in_array($i['thr_parent'], $mids)) {
                        continue;
                    }

                    if ((!$to) || (!in_array($observer['xchan_url'], $to))) {
                        continue;
                    }
                }
                $nitems[] = $i;
            }

            if (!$nitems) {
                http_status_exit(404, 'Not found');
            }

            $chan = Channel::from_id($nitems[0]['uid']);

            if (!$chan) {
                http_status_exit(404, 'Not found');
            }

            if (!perm_is_allowed($chan['channel_id'], get_observer_hash(), 'view_stream')) {
                http_status_exit(403, 'Forbidden');
            }

            $i = ZlibActivity::encode_item_collection($nitems, 'conversation/' . $item_id, 'OrderedCollection', true, count($nitems));
            if ($portable_id && (!intval($items[0]['item_private']))) {
                ThreadListener::store(z_root() . '/activity/' . $item_id, $portable_id);
            }

            if (!$i) {
                http_status_exit(404, 'Not found');
            }

            $x = array_merge(ZlibActivity::ap_context(), $i);

            $headers = [];
            $headers['Content-Type'] = 'application/x-nomad+json';
            $x['signature'] = LDSignatures::sign($x, $chan);
            $ret = json_encode($x, JSON_UNESCAPED_SLASHES);
            $headers['Digest'] = HTTPSig::generate_digest_header($ret);
            $headers['(request-target)'] = strtolower($_SERVER['REQUEST_METHOD']) . ' ' . $_SERVER['REQUEST_URI'];
            $h = HTTPSig::create_sig($headers, $chan['channel_prvkey'], Channel::url($chan));
            HTTPSig::set_headers($h);
            echo $ret;
            killme();
        }


        goaway(z_root() . '/item/' . argv(1));
    }
}