九、从零模拟新浪微博-关注和取消关注

代码仓库：https://github.com/changeclass/koa2-weibo

数据模型

1. 模型

   /**
    * @description:用户关注关系
    * @author: 小康
    * @url: https://xiaokang.me
    * @Date: 2020-12-19 15:31:54
    * @LastEditTime: 2020-12-19 15:31:55
    * @LastEditors: 小康
    */
   
   const seq = require('../seq')
   const { INTEGER } = require('../type')
   const UserRelation = seq.define('userRelation', {
     userId: {
       type: INTEGER,
       allowNull: false,
       comment: '用户ID'
     },
     followerId: {
       type: INTEGER,
       allowNull: false,
       comment: '被关注用户的ID'
     }
   })
   module.exports = UserRelation

2. 创建关系

   /**
    * @description 数据模型入口文件
    * @author 小康
    */
   
   const User = require('./User')
   const Blog = require('./Blog')
   const UserRelation = require('./UserRelation')
   // 创建外键
   Blog.belongsTo(User, {
     foreignKey: 'userId'
   })
   
   UserRelation.belongsTo(User, {
     foreignKey: 'followerId'
   })
   User.hasMany(UserRelation, {
     foreignKey: 'userId'
   })
   
   module.exports = {
     User,
     Blog,
     UserRelation
   }

粉丝列表

1. 控制器层

   /**
    * @description: 用户关系的controller
    * @author: 小康
    * @url: https://xiaokang.me
    * @Date: 2020-12-19 15:49:12
    * @LastEditTime: 2020-12-19 15:49:12
    * @LastEditors: 小康
    */
   
   const { SuccessModel } = require('../model/ResModel')
   const { getUsersByFollower } = require('../services/user-relation')
   
   /**
    * @author: 小康
    * @url: https://xiaokang.me
    * @param {number} userId 用户id
    * @description: 根据用户id获取粉丝列表
    */
   async function getFans(userId) {
     // service
     const { count, userList } = await getUsersByFollower(userId)
     return new SuccessModel({ count, userList })
   }
   
   module.exports = {
     getFans
   }
   

2. 服务层

   /**
    * @description: 用户关系 services
    * @author: 小康
    * @url: https://xiaokang.me
    * @Date: 2020-12-19 15:50:52
    * @LastEditTime: 2020-12-19 15:50:52
    * @LastEditors: 小康
    */
   const { User, UserRelation } = require('../db/model/index')
   const { formatUser } = require('./_format')
   
   /**
    * @author: 小康
    * @url: https://xiaokang.me
    * @param {number} followerId 被关注人的ID
    * @description: 获取关注该用户的用户列表
    */
   async function getUsersByFollower(followerId) {
     const result = await User.findAndCountAll({
       attributes: ['id', 'userName', 'nickName', 'picture'],
       order: [['id', 'desc']],
       include: [{ model: UserRelation, where: { followerId } }]
     })
     // 格式化
     let userList = result.rows.map((row) => row.dataValues)
     userList = formatUser(userList)
     return { count: result.count, userList }
   }
   
   module.exports = {
     getUsersByFollower
   }

判断关注状态

const { count: fansCount, userList: fansList } = fansResult.data
// 我是否关注了此人

const amIFollowed = fansList.some((item) => {
  return item.userName === myUserName
})

关注和取消关注

1. api路由层

   // 关注用户
   router.post('/follow', loginCheck, async (ctx, next) => {
     const { id: myUserId } = ctx.session.userInfo
     const { userId: curUserId } = ctx.request.body
     // controller
     ctx.body = await follow(myUserId, curUserId)
   })
   // 取消关注
   router.post('/unFollow', loginCheck, async (ctx, next) => {
     const { id: myUserId } = ctx.session.userInfo
     const { userId: curUserId } = ctx.request.body
     // controller
     ctx.body = await unFollow(myUserId, curUserId)
   })

2. 控制器层

   /**
    * @author: 小康
    * @url: https://xiaokang.me
    * @param {*} myUserId 我的ID
    * @param {*} curUserId 当前登录的用户ID
    * @description: 关注
    */
   async function follow(myUserId, curUserId) {
     try {
       await addFollow(myUserId, curUserId)
       return new SuccessModel()
     } catch (err) {
       return new ErrorModel(addFollowerFailInfo)
     }
   }
   
   /**
    * @author: 小康
    * @url: https://xiaokang.me
    * @param {*} myUserId 我的ID
    * @param {*} curUserId 当前登录的用户ID
    * @description: 取消关注
    */
   async function unFollow(myUserId, curUserId) {
     const result = await deleteFollow(myUserId, curUserId)
     if (result) {
       return new SuccessModel()
     } else {
       return new ErrorModel(deleteUserFailInfo)
     }
   }

3. 服务层

   /**
    * @author: 小康
    * @url: https://xiaokang.me
    * @param {number} userId 用户ID
    * @param {number} followerId 被关注用户id
    * @description: 添加关注关系
    */
   async function addFollow(userId, followerId) {
     const result = await UserRelation.create({
       userId,
       followerId
     })
     return result.dataValues
   }
   /**
    * @author: 小康
    * @url: https://xiaokang.me
    * @param {number} userId 用户ID
    * @param {number} followerId 被关注用户id
    * @description: 取消关注关系
    */
   async function deleteFollow(userId, followerId) {
     const result = await UserRelation.destroy({
       where: { userId, followerId }
     })
     return result > 0
   }