koa2-微博项目

初始化项目

创建项目

koa2 -e koa2-weibo

初始化git仓库

git init

git remote add origin ''

git pull origin master

git add .

git commit -m "init project"

git push origin master

创建新分支，并推送到码云

git checkout -b users

git push -u origin users

合并

git merge users

设置环境变量

1.安装cross-env依赖到生产环境中
2.对package.json设置
    "dev": "cross-env NODE_ENV=dev ./node_modules/.bin/nodemon bin/www",
    "prd": "cross-env NODE_ENV=production pm2 start bin/www",

koa2基础知识

简单请求

get

router.get('/loadMore/:userName/:pageIndex', async (ctx, next) => {
  const { userName, pageIndex } = ctx.params
  ctx.body = {
    title: 'this is profile page',
    userName,
    pageIndex
  }
})

post

router.post('/login', async (ctx, next) => {
  const { userName, password } = ctx.request.body;
  ctx.body = {
    code:0,
    userName,
    password
  }
})

ejs

• 获取ctx.body里的变量 <%= title %>
• 判断

<%= if (isMe) { %>
<%= } else { %>
<%= } %>

• 引用组件

<%- include('组件路径', {
	参数
})%>

• 循环

<% blogList.forEach(item => { %>

<% }) %>

mysql，创建外键，连表查询

-- select * from users;
-- SELECT * FROM blogs;
-- insert into users (username,`password`,nickname) values ('lisi','123','李四');
-- select username,nickname from users where username='lisi' and `password`=123;
-- insert into blogs (title,content,userid) values ('标题5','内容5',3);
-- update blogs set content='内容1内容一' where id=2;
-- delete from users where id=2;

-- 查询总数，as别名
-- select count(id) as `count` from blogs;

-- 根据id倒序查询，限制2个，跳过2行
-- select * from blogs order by id desc limit 2 offset 2;

-- 连表查询
-- select * from blogs inner join users on users.id = blogs.userid;

sequelize

安装依赖

yarn add mysql2 sequelize 

创建sequelize实例 sequelize.js

const Sequelize = require('sequelize');

const config = {
  host: 'localhost',
  dialect: 'mysql'
}

const sequelize = new Sequelize('koa2_weibo_db', 'root', '123456', config);

// 测试连接

// sequelize.authenticate().then(()=>{
//   console.log('ok');
// }).catch(()=>{
//   console.log(err);
// })

module.exports = sequelize

建模 index.js

const Sequelize = require('sequelize');
const sequelize = require('../sequelize');

// 创建User模型(数据表的名字是 users)

const User = sequelize.define('user', {
  // id会自动创建，并设为主键、自增
  userName: {
    type: Sequelize.STRING,//varchar(255)
    allowNull:false
  },
  password: {
    type: Sequelize.STRING,
    allowNull: false
  },
  nickName: {
    type: Sequelize.STRING,
    comment:'昵称'
  },

  // 自动创建：createdAt和uodatedAt
})

// 创建 Blog 模型
const Blog = sequelize.define('blog', {
  // id会自动创建，并设为主键、自增
  title: {
    type: Sequelize.STRING,
    allowNULL: false
  },
  content: {
    type: Sequelize.STRING,
    allowNULL: false
  },
  userId: {
    type: Sequelize.INTEGER,
    allowNULL: false
  },

  // 自动创建：createdAt和uodatedAt
})

// 外键关联

// 第一种方法
Blog.belongsTo(User,{
  // 创建外键 Blog.userId -> User.id
  // 默认关联id
  foreignKey:'userId'
})

// 第二种方法
User.hasMany(Blog,{
  // 创建外键 Blog.userId -> User.id
  // 默认关联id
  foreignKey: 'userId'
})


module.exports = {
  User,
  Blog
}

同步到数据库 sync.js

const sequelize=require('../sequelize');

require('./index');

// 测试连接

sequelize.authenticate().then(()=>{
  console.log('ok');
}).catch(()=>{
  console.log(err);
})

// 执行同步
sequelize.sync({force:true}).then(()=>{
  process.exit()
})

增 create.js

const { Blog, User } = require('./index');

(async () => {
  // 创建用户
  const zhangsan = await User.create({
    userName: 'zhangsan',
    password: '123',
    nickName: '张三'
  })

  // console.log('zhangsan', zhangsan.dataValues);
  const zhangsanId = zhangsan.dataValues.id;

  const lisi = await User.create({
    userName: 'lisi',
    password: '123',
    nickName: '李四'
  })
  const lisiId = lisi.dataValues.id;


  // 创建博客

  const blog1 = await Blog.create({
    title: '标题1',
    content: '内容1',
    userId: zhangsanId
  })

  const blog2 = await Blog.create({
    title: '标题2',
    content: '内容2',
    userId: zhangsanId
  })

  const blog3 = await Blog.create({
    title: '标题3',
    content: '内容3',
    userId: lisiId
  })

  const blog4 = await Blog.create({
    title: '标题4',
    content: '内容4',
    userId: lisiId
  })

  console.log('blog1',blog1.dataValues);



})()

查 select.js

const { Blog, User } = require('./index');

(async () => {

  // 查询一条数据
  const zhangsan = await User.findOne({
    where: {
      userName: 'zhangsan'
    }
  })

  // console.log('zhangsan', zhangsan.dataValues);

  // 查询特定的列

  const zhangsanName = await User.findOne({
    attributes: ['userName', 'nickName'],
    where: {
      userName: 'zhangsan'
    }
  })

  // console.log('zhangsanName', zhangsanName.dataValues);

  // 查询一个列表
  const zhangsanBlogList = await Blog.findAll({
    where: {
      userId: 1
    },
    // 排序
    order: [
      ['id', 'desc']
    ]
  })
  // console.log('zhangsanBlogList', zhangsanBlogList.map(blog => blog.dataValues));

  // 分页
  const blogPageList = await Blog.findAll({
    limit: 2,// 限制本次查询两条
    offset: 0,// 跳过多少条
    order: [
      ['id', 'desc']
    ]
  })

  // console.log('blogPageList', blogPageList.map(blog => blog.dataValues));

  // 查询总数

  const blogListAndCount = await Blog.findAndCountAll({
    limit: 2,// 限制本次查询两条
    offset: 0,// 跳过多少条
    order: [
      ['id', 'desc']
    ]
  })

  // console.log(
  //   'blogListAndCount',
  //   blogListAndCount.count,//所有的总数，不考虑分页
  //   blogListAndCount.rows.map(blog => blog.dataValues)
  // );

  // 连表查询1 Blog->User
  const blogListWithUser = await Blog.findAndCountAll({
    order: [
      ['id', 'desc']
    ],
    include: [
      {
        model: User,
        attributes: ['userName', 'nickName'],
        where: {
          userName: 'zhangsan'
        }
      }
    ]
  })

  // console.log(
  //   'blogListWithUser',
  //   blogListWithUser.count,
  //   blogListWithUser.rows.map(blog => {
  //     const blogVal = blog.dataValues;
  //     blogVal.user = blogVal.user.dataValues
  //     return blogVal
  //   })
  // );

  // 连表查询2 User->Blog
  const userListWithBlog = await User.findAndCountAll({
    attributes: ['userName', 'nickName'],
    include: [
      {
        model: Blog
      }
    ]
  })

  // console.log(
  //   'userListWithBlog',
  //   userListWithBlog.count,
  //   userListWithBlog.rows.map(user => {
  //     const userVal = user.dataValues;
  //     userVal.blogs = userVal.blogs.map(blog => blog.dataValues)
  //     return userVal
  //   })
  // );



})()

改 update.js

const { User } = require('./index');

(async () => {
  const updateRes = await User.update({
    nickName: '张三1'
  }, {
    where: {
      userName: 'zhangsan'
    }
  })

  console.log('updateRes', updateRes[0] > 0);
})()

删

const { User, Blog } = require('./index');

(async () => {

  // 删除一条博客
  const delBlogRes = await Blog.destroy({
    where: {
      id: 4
    }
  })

  // console.log('delBlogRes', delBlogRes > 0);

  // 删除一个用户,其对应博客也跟着删除

  const delUserRes = await User.destroy({
    where:{
      id:1
    }
  })

  console.log('delUserRes', delUserRes);
})()

mongodb(文档存储)

安装

brew tap mongodb/brew

brew install mongodb-community

brew services start mongodb/brew/mongodb-community

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/mongoose_test', { useNewUrlParser: true, useUnifiedTopology: true });

mongoose.connection.on('connected', () => {
  console.log('连接成功')
})
mongoose.connection.on('error', () => {
  console.log('error')
})
mongoose.connection.on('disconnected', () => {
  console.log('断开连接')
})

const userSchema = new mongoose.Schema({
  name: { type: String, required: true },
  age: { type: Number, default: 0 }
})

const User = mongoose.model('User', userSchema);

(async () => {

  const UserCreate = await User.create({ name: '小明', age: 13 })

  // console.log(UserCreate);

  const UserFind = await User.find();

  // console.log(UserFind);

  const UserUpdate = await User.update({name:'小明'},{$set:{age:18}})

  // console.log(UserUpdate);
  const UserRemove = await User.remove({name:'小明'})


})()