[PLUGIN][ActivityPub] Finish base ActivityStreams 2.0 interface

Instructions below

To extend an Activity properties do:

public function onActivityPubValidateActivityStreamsTwoData(string $type_name, array &$validators): bool {
    if ($type_name === '{Type}') {
        $validators['attribute'] = myValidator::class;
    }
    return Event::next;
}

The Validator should be of the form:

use ActivityPhp\Type;
use ActivityPhp\Type\Util;
use Plugin\ActivityPub\Util\ModelValidator;

class myValidator extends ModelValidator
{
    /**
     * Validate Attribute's value
     *
     * @param mixed $value from JSON's attribute
     * @param mixed $container A {Type}
     * @return bool
     * @throws Exception
     */
    public function validate($value, $container): bool
    {
        // Validate that container is a {Type}
        Util::subclassOf($container, Type\Extended\Object\{Type}::class, true);

        return {Validation Result};

To act on received activities do:

public function onActivityPubNew{Type}(&$obj): bool {

To add information to Activities being federated by ActivityPub do:

public function ActivityPubAddActivityStreamsTwoData(string $type_name, &$type): bool {

To implement an ActivityStreams 2.0 representation do:

public function onActivityPubActivityStreamsTwoResponse(string $route, arrray $vars, ?TypeResponse &$response = null): bool {
        if ($route === '{Object route}') {
                $response = ModelResponse::handle($vars[{Object}]);
                return Event::stop;
        }
        return Event::next;
}

plugins/ActivityPub/Util/Model/Note.php

@@ -0,0 +1,145 @@
+<?php
+
+declare(strict_types=1);
+
+// {{{ License
+// 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 2021 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+
+namespace Plugin\ActivityPub\Util\Model;
+
+use ActivityPhp\Type\AbstractObject;
+use App\Core\Event;
+use App\Core\Router\Router;
+use App\Entity\Actor;
+use App\Entity\Language;
+use App\Entity\Note as GSNote;
+use App\Util\Formatting;
+use DateTime;
+use DateTimeInterface;
+use Exception;
+use InvalidArgumentException;
+use Plugin\ActivityPub\ActivityPub;
+use Plugin\ActivityPub\Util\Model;
+
+/**
+ * This class handles translation between JSON and GSNotes
+ *
+ * @copyright 2021 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+class Note extends Model
+{
+
+    /**
+     * Create an Entity from an ActivityStreams 2.0 JSON string
+     * This will persist a new GSNote
+     *
+     * @param string|AbstractObject $json
+     * @param array $options
+     * @return GSNote
+     * @throws Exception
+     */
+    public static function fromJson(string|AbstractObject $json, array $options = []): GSNote
+    {
+        $source = $options['source'];
+        $actor_uri = $options['actor_uri'];
+        $actor_id = $options['actor_id'];
+        $type_note = is_string($json) ? self::jsonToType($json) : $json;
+
+        if (is_null($actor_uri) || $actor_uri !== $type_note->get('attributedTo')) {
+            $actor_id = ActivityPub::getActorByUri($type_note->get('attributedTo'))->getId();
+        }
+        $map = [
+            'is_local' => false,
+            'created' => new DateTime($type_note->get('published') ?? 'now'),
+            'content' => $type_note->get('content') ?? null,
+            'content_type' => 'text/html',
+            'language_id' => $type_note->get('contentLang') ?? null,
+            'url' => $type_note->get('url') ?? $type_note->get('id'),
+            'actor_id' => $actor_id,
+            'modified' => new DateTime(),
+            'source' => $source,
+        ];
+        if ($map['content'] !== null) {
+            $mentions = [];
+            Event::handle('RenderNoteContent', [
+                $map['content'],
+                $map['content_type'],
+                &$map['rendered'],
+                Actor::getById($actor_id),
+                $map['language_id'],
+                &$mentions,
+            ]);
+        }
+
+        $obj = new GSNote();
+
+        if (!is_null($map['language_id'])) {
+            $map['language_id'] = Language::getFromLocale($map['language_id'])->getId();
+        } else {
+            $map['language_id'] = null;
+        }
+
+        foreach ($map as $prop => $val) {
+            $set = Formatting::snakeCaseToCamelCase("set_{$prop}");
+            $obj->{$set}($val);
+        }
+
+        Event::handle('ActivityPubNewNote', [&$obj]);
+        return $obj;
+    }
+
+    /**
+     * Get a JSON
+     *
+     * @param mixed $object
+     * @param int|null $options
+     * @return string
+     * @throws Exception
+     */
+    public static function toJson(mixed $object, ?int $options = null): string
+    {
+        if ($object::class !== 'App\Entity\Note') {
+            throw new InvalidArgumentException('First argument type is Note');
+        }
+
+        $attr = [
+            '@context' => 'https://www.w3.org/ns/activitystreams',
+            'id' => Router::url('note_view', ['id' => $object->getId()], Router::ABSOLUTE_URL),
+            'published' => $object->getCreated()->format(DateTimeInterface::RFC3339),
+            'attributedTo' => $object->getActor()->getUri(Router::ABSOLUTE_URL),
+            'to' => ['https://www.w3.org/ns/activitystreams#Public'], // TODO: implement proper scope address
+            'cc' => ['https://www.w3.org/ns/activitystreams#Public'],
+            'content' => $object->getRendered(),
+            //'tag' => $tags
+        ];
+
+        $type = self::jsonToType($attr);
+        Event::handle('ActivityPubAddActivityStreamsTwoData', [$type->get('type'), &$type]);
+        return $type->toJson($options);
+    }
+}