Add new item/{id}/follow module and POST route

- It is meant to replace mod/subthread

src/Module/Item/Follow.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * @copyright Copyright (C) 2020, Friendica
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Module\Item;
+
+use Friendica\BaseModule;
+use Friendica\Core\Session;
+use Friendica\Core\System;
+use Friendica\DI;
+use Friendica\Model\Item;
+use Friendica\Model\Post;
+use Friendica\Network\HTTPException;
+
+/**
+ * Module for following threads
+ */
+class Follow extends BaseModule
+{
+	public static function rawContent(array $parameters = [])
+	{
+		$l10n = DI::l10n();
+
+		if (!Session::isAuthenticated()) {
+			throw new HttpException\ForbiddenException($l10n->t('Access denied.'));
+		}
+
+		if (empty($parameters['id'])) {
+			throw new HTTPException\BadRequestException();
+		}
+
+		$itemId = intval($parameters['id']);
+
+		if (!Item::performActivity($itemId, 'follow', local_user())) {
+			throw new HTTPException\BadRequestException($l10n->t('Unable to follow this item.'));
+		}
+
+		// See if we've been passed a return path to redirect to
+		$return_path = $_REQUEST['return'] ?? '';
+		if (!empty($return_path)) {
+			$rand = '_=' . time();
+			if (strpos($return_path, '?')) {
+				$rand = "&$rand";
+			} else {
+				$rand = "?$rand";
+			}
+
+			DI::baseUrl()->redirect($return_path . $rand);
+		}
+
+		$return = [
+			'status' => 'ok',
+			'item_id' => $itemId,
+			'verb' => 'follow',
+			'state' => 1
+		];
+
+		System::jsonExit($return);
+	}
+}

static/routes.config.php

@@ -290,11 +290,12 @@ return [
 		'/testrewrite'           => [Module\Install::class, [R::GET]],
 	],
 
-	'/item'            => [
-		'/{id:\d+}/activity/{verb}' => [Module\Item\Activity::class,    [        R::POST]],
-		'/{id:\d+}/ignore'          => [Module\Item\Ignore::class,      [        R::POST]],
-		'/{id:\d+}/pin'             => [Module\Item\Pin::class,         [        R::POST]],
-		'/{id:\d+}/star'            => [Module\Item\Star::class,        [        R::POST]],
+	'/item/{id:\d+}'            => [
+		'/activity/{verb}' => [Module\Item\Activity::class,    [        R::POST]],
+		'/follow'          => [Module\Item\Follow::class,      [        R::POST]],
+		'/ignore'          => [Module\Item\Ignore::class,      [        R::POST]],
+		'/pin'             => [Module\Item\Pin::class,         [        R::POST]],
+		'/star'            => [Module\Item\Star::class,        [        R::POST]],
 	],
 
 	'/localtime'          => [Module\Debug\Localtime::class, [R::GET, R::POST]],