Redis实现用户关注的项目实践

// 添加关注
router.post('/followers/:id', async (req, res) => {
  try {
    const followerId = req.user.id;
    const followingId = req.params.id;

    // 获取被关注的用户和关注该用户的用户
    const following = await User.findById(followingId);
    const follower = await User.findById(followerId);

    // 添加关注对象
    await redis.sadd(`user:${followerId}:following`, followingId);
    await redis.sadd(`user:${followingId}:followers`, followerId);

    res.json({ message: `You are now following ${following.username}` });
  } catch (error) {
    console.error(error.message);
    res.status(500).send('Server Error');
  }
});

// 取消关注
router.delete('/followers/:id', async (req, res) => {
 try {
    const followerId = req.user.id;
    const followingId = req.params.id;

    // 获取被取消关注的用户和取消关注该用户的用户
    const following = await User.findById(followingId);
    const follower = await User.findById(followerId);

    // 删除关注对象
    await redis.srem(`user:${followerId}:following`, followingId);
    await redis.srem(`user:${followingId}:followers`, followerId);

    res.json({ message: `You have unfollowed ${following.username}` });
  } catch (error) {
    console.error(error.message);
    res.status(500).send('Server Error');
  }
});

// 获取关注和粉丝
router.get('/followers', async (req, res) => {
  try {
    const userId = req.user.id;

    // 获取关注和被关注的set
    const [following, followers] = await Promise.all([
      redis.smembers(`user:${userId}:following`),
      redis.smembers(`user:${userId}:followers`),
    ]);

    // 将id转换为用户对象
    const followingUsers = await Promise.all(
      following.map((id) => User.findById(id))
    );
    const followerUsers = await Promise.all(
      followers.map((id) => User.findById(id))
    );

    res.json({ following: followingUsers, followers: followerUsers });
  } catch (error) {
    console.error(error.message);
    res.status(500).send('Server Error');
  }
});

<!-- 添加关注 -->
<button @click="followUser(user._id)" v-if="!isFollowing(user._id)">关注</button>

<!-- 取消关注 -->
<button @click="unfollowUser(user._id)" v-else>取消关注</button>

methods: {
  // 添加关注
  async followUser(id) {
    await axios.post(`/api/followers/${id}`);
    // 更新关注状态
    this.isFollowingUsers[id] = true;
  },
  // 取消关注
  async unfollowUser(id) {
    await axios.delete(`/api/followers/${id}`);
    // 更新关注状态
    this.isFollowingUsers[id] = false;
  },
  // 判断是否关注
  isFollowing(id) {
    return this.isFollowingUsers[id];
  }
}

// 获取关注和粉丝数量
router.get('/followers/count', async (req, res) => {
  try {
    const userId = req.user.id;

    // 获取关注和被关注数量
    const [followingCount, followerCount] = await Promise.all([
      redis.scard(`user:${userId}:following`),
      redis.scard(`user:${userId}:followers`),
    ]);

    res.json({ followingCount, followerCount });
  } catch (error) {
    console.error(error.message);
    res.status(500).send('Server Error');
  }
});

<!-- 显示关注和被关注数量 -->
<div>
  <p>关注 {{followingCount}}</p>
  <p>被关注 {{followerCount}}</p>
</div>