feat(feed): Add a follow a topic API

app/API2/Controllers/Feed/TopicFollow.php

@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * +----------------------------------------------------------------------+
+ * |                          ThinkSNS Plus                               |
+ * +----------------------------------------------------------------------+
+ * | Copyright (c) 2018 Chengdu ZhiYiChuangXiang Technology Co., Ltd.     |
+ * +----------------------------------------------------------------------+
+ * | This source file is subject to version 2.0 of the Apache license,    |
+ * | that is bundled with this package in the file LICENSE, and is        |
+ * | available through the world-wide-web at the following url:           |
+ * | http://www.apache.org/licenses/LICENSE-2.0.html                      |
+ * +----------------------------------------------------------------------+
+ * | Author: Slim Kit Group <master@zhiyicx.com>                          |
+ * | Homepage: www.thinksns.com                                           |
+ * +----------------------------------------------------------------------+
+ */
+
+namespace Zhiyi\Plus\API2\Controllers\Feed;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Response;
+use Zhiyi\Plus\API2\Controllers\Controller;
+use Zhiyi\Plus\Models\FeedTopic as FeedTopicModel;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+
+class TopicFollow extends Controller
+{
+    /**
+     * Create the controller instance.
+     */
+    public function __construct()
+    {
+        $this->middleware('auth:api');
+    }
+
+    /**
+     * Follow a topic.
+     * 
+     * @param \Illuminate\Http\Request $request
+     * @param \Zhiyi\Plus\Models\FeedTopic $model
+     * @param int $topicID
+     * @return \Illuminate\Http\Response
+     */
+    public function follow(Request $request, FeedTopicModel $model, int $topicID): Response
+    {
+        // Featch the request authentication user model.
+        $user = $request->user();
+
+        // Database query topic.
+        $topic = $model
+            ->query()
+            ->where('id', $topicID)
+            ->first();
+
+        // If the topic Non-existent, throw a not found exception.
+        if (!$topic) {
+            throw new NotFoundHttpException('关注的话题不存在');
+        }
+
+        // Create success 204 response
+        $response = (new Response())->setStatusCode(Response::HTTP_NO_CONTENT /* 204 */);
+
+        // Database query the authentication user followed.
+        $exists = $topic
+            ->followers()
+            ->where('user_id', $user->id)
+            ->exists();
+        if ($exists) {
+            return $response;
+        }
+
+        return $user->getConnection()->transaction(function () use ($user, $topic, $response): Response {
+            $topic->followers()->attach($user);
+            $topic->followers_count += 1;
+            $topic->save();
+
+            return $response;
+        });
+    }
+}

routes/api.php

@@ -660,4 +660,12 @@
             $api->post('', \Zhiyi\Plus\API2\Controllers\Feed\Topic::class.'@create');
         });
     });
+
+    /*
+     * Follow a topic.
+     * 
+     * @Put /api/v2/user/feed-topics/:topicID
+     * @Response::header('Status', 204, 'No Content')
+     */
+    $api->put('user/feed-topics/{topicID}', \Zhiyi\Plus\API2\Controllers\Feed\TopicFollow::class.'@follow');
 });