gnu-social/plugins/ActivityPub/Util/Explorer.php

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<?php
declare(strict_types=1);
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// {{{ License
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// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social. If not, see <http://www.gnu.org/licenses/>.
// }}}
/**
* ActivityPub implementation for GNU social
*
* @package GNUsocial
* @category ActivityPub
* @author Diogo Peralta Cordeiro <@diogo.site>
* @copyright 2018-2019, 2021 Free Software Foundation, Inc http://www.fsf.org
* @license https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
*/
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namespace Plugin\ActivityPub\Util;
use App\Core\HTTPClient;
use App\Core\Log;
use App\Util\Exception\NoSuchActorException;
use Exception;
use Plugin\ActivityPub\ActivityPub;
use Plugin\ActivityPub\Entity\ActivitypubActor;
use Symfony\Contracts\HttpClient\Exception\ClientExceptionInterface;
use Symfony\Contracts\HttpClient\Exception\RedirectionExceptionInterface;
use Symfony\Contracts\HttpClient\Exception\ServerExceptionInterface;
use Symfony\Contracts\HttpClient\Exception\TransportExceptionInterface;
use function in_array;
use function is_null;
use const JSON_UNESCAPED_SLASHES;
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/**
* ActivityPub's own Explorer
*
* Allows to discovery new remote actors
*
* @copyright 2021 Free Software Foundation, Inc http://www.fsf.org
* @license https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
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*/
class Explorer
{
private array $discovered_actor_profiles = [];
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/**
* Shortcut function to get a single profile from its URL.
*
* @param string $url
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* @param bool $grab_online whether to try online grabbing, defaults to true
*
* @return ActivitypubActor
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* @throws ClientExceptionInterface
* @throws NoSuchActorException
* @throws RedirectionExceptionInterface
* @throws ServerExceptionInterface
* @throws TransportExceptionInterface
*/
public static function get_profile_from_url(string $url, bool $grab_online = true): ActivitypubActor
{
$discovery = new self();
// Get valid Actor object
$actor_profile = $discovery->lookup($url, $grab_online);
if (!empty($actor_profile)) {
return $actor_profile[0];
}
throw new NoSuchActorException('Invalid Actor.');
}
/**
* Get every profile from the given URL
* This function cleans the $this->discovered_actor_profiles array
* so that there is no erroneous data
*
* @param string $url User's url
* @param bool $grab_online whether to try online grabbing, defaults to true
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*
* @throws ClientExceptionInterface
* @throws NoSuchActorException
* @throws RedirectionExceptionInterface
* @throws ServerExceptionInterface
* @throws TransportExceptionInterface
*
* @return array of Actor objects
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*/
public function lookup(string $url, bool $grab_online = true)
{
if (in_array($url, ActivityPub::PUBLIC_TO)) {
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return [];
}
Log::debug('ActivityPub Explorer: Started now looking for ' . $url);
$this->discovered_actor_profiles = [];
return $this->_lookup($url, $grab_online);
}
/**
* Get every profile from the given URL
* This is a recursive function that will accumulate the results on
* $discovered_actor_profiles array
*
* @param string $url User's url
* @param bool $grab_online whether to try online grabbing, defaults to true
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*
* @throws ClientExceptionInterface
* @throws NoSuchActorException
* @throws RedirectionExceptionInterface
* @throws ServerExceptionInterface
* @throws TransportExceptionInterface
*
* @return array of Profile objects
*/
private function _lookup(string $url, bool $grab_online = true): array
{
$grab_known = $this->grab_known_user($url);
// First check if we already have it locally and, if so, return it.
// If the known fetch fails and remote grab is required: store locally and return.
if (!$grab_known && (!$grab_online || !$this->grab_remote_user($url))) {
throw new NoSuchActorException('Actor not found.');
}
return $this->discovered_actor_profiles;
}
/**
* Get a known user profile from its URL and joins it on
* $this->discovered_actor_profiles
*
* @param string $uri Actor's uri
*
* @throws Exception
* @throws NoSuchActorException
*
* @return bool success state
*/
private function grab_known_user(string $uri): bool
{
Log::debug('ActivityPub Explorer: Searching locally for ' . $uri . ' offline.');
// Try standard ActivityPub route
// Is this a known filthy little mudblood?
$aprofile = self::get_aprofile_by_url($uri);
if ($aprofile instanceof ActivitypubActor) {
Log::debug('ActivityPub Explorer: Found a known Aprofile for ' . $uri);
// We found something!
$this->discovered_actor_profiles[] = $aprofile;
return true;
} else {
Log::debug('ActivityPub Explorer: Unable to find a known Aprofile for ' . $uri);
}
return false;
}
/**
* Get a remote user(s) profile(s) from its URL and joins it on
* $this->discovered_actor_profiles
*
* @param string $url User's url
*
* @throws ClientExceptionInterface
* @throws NoSuchActorException
* @throws RedirectionExceptionInterface
* @throws ServerExceptionInterface
* @throws TransportExceptionInterface
*
* @return bool success state
*/
private function grab_remote_user(string $url): bool
{
Log::debug('ActivityPub Explorer: Trying to grab a remote actor for ' . $url);
$response = HTTPClient::get($url, ['headers' => ACTIVITYPUB::HTTP_CLIENT_HEADERS]);
$res = json_decode($response->getContent(), true);
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if ($response->getStatusCode() == 410) { // If it was deleted
return true; // Nothing to add.
} elseif (!HTTPClient::statusCodeIsOkay($response)) { // If it is unavailable
return false; // Try to add at another time.
}
if (is_null($res)) {
Log::debug('ActivityPub Explorer: Invalid response returned from given Actor URL: ' . $res);
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return true; // Nothing to add.
}
if ($res['type'] === 'OrderedCollection') { // It's a potential collection of actors!!!
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Log::debug('ActivityPub Explorer: Found a collection of actors for ' . $url);
$this->travel_collection($res['first']);
return true;
} else {
try {
$this->discovered_actor_profiles[] = Model\Actor::fromJson(json_encode($res));
return true;
} catch (Exception $e) {
Log::debug(
'ActivityPub Explorer: Invalid potential remote actor while grabbing remotely: ' . $url
. '. He returned the following: ' . json_encode($res, JSON_UNESCAPED_SLASHES)
. ' and the following exception: ' . $e->getMessage()
);
return false;
}
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}
return false;
}
/**
* Validates a remote response in order to determine whether this
* response is a valid profile or not
*
* @param array $res remote response
*
* @return bool success state
*/
public static function validate_remote_response(array $res): bool
{
return !(!isset($res['id'], $res['preferredUsername'], $res['inbox'], $res['publicKey']['publicKeyPem']));
}
/**
* Get a ActivityPub Profile from it's uri
*
* @param string $v URL
*
* @return ActivitypubActor|bool false if fails | Aprofile object if successful
*/
public static function get_aprofile_by_url(string $v): ActivitypubActor|bool
{
$aprofile = ActivitypubActor::getWithPK(['uri' => $v]);
return is_null($aprofile) ? false : ActivitypubActor::getWithPK(['uri' => $v]);
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}
/**
* Allows the Explorer to transverse a collection of persons.
*
* @param string $url
* @return bool
* @throws ClientExceptionInterface
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* @throws NoSuchActorException
* @throws RedirectionExceptionInterface
* @throws ServerExceptionInterface
* @throws TransportExceptionInterface
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*/
private function travel_collection(string $url): bool
{
$response = HTTPClient::get($url, ['headers' => ACTIVITYPUB::HTTP_CLIENT_HEADERS]);
$res = json_decode($response->getContent(), true);
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if (!isset($res['orderedItems'])) {
return false;
}
foreach ($res['orderedItems'] as $profile) {
if ($this->_lookup($profile) == false) {
Log::debug('ActivityPub Explorer: Found an invalid actor for ' . $profile);
}
}
// Go through entire collection
if (!is_null($res['next'])) {
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$this->travel_collection($res['next']);
}
return true;
}
/**
* Get a remote user array from its URL (this function is only used for
* profile updating and shall not be used for anything else)
*
* @param string $url User's url
*
* @throws ClientExceptionInterface
* @throws RedirectionExceptionInterface
* @throws ServerExceptionInterface
* @throws TransportExceptionInterface
*
* @return array|false If it is able to fetch, false if it's gone
* // Exceptions when network issues or unsupported Activity format
*/
public static function get_remote_user_activity(string $url): bool|array
{
$response = HTTPClient::get($url, ['headers' => ACTIVITYPUB::HTTP_CLIENT_HEADERS]);
// If it was deleted
if ($response->getStatusCode() == 410) {
return false;
} elseif (!HTTPClient::statusCodeIsOkay($response)) { // If it is unavailable
throw new Exception('Non Ok Status Code for given Actor URL.');
}
$res = json_decode($response->getContent(), true);
if (is_null($res)) {
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Log::debug('ActivityPub Explorer: Invalid JSON returned from given Actor URL: ' . $response->getContent());
throw new Exception('Given Actor URL didn\'t return a valid JSON.');
}
if (self::validate_remote_response($res)) {
Log::debug('ActivityPub Explorer: Found a valid remote actor for ' . $url);
return $res;
}
throw new Exception('ActivityPub Explorer: Failed to get activity.');
}
}