Detailed explanation of the steps to build the Koa project

This time I will bring you a detailed explanation of the steps to build the Koa project. What are the precautions for building the Koa project? The following is a practical case, let’s take a look.

This article introduces the detailed record of the Koa project construction process and shares it with everyone. The details are as follows:

Spring MVC plus MyBatis in Java has basically become Java Web standard. Corresponding to Node JS are Koa, Express, Mongoose, Sequelize, etc. Koa can be said to be an upgraded version of Express to a certain extent. Many Node JS projects have begun using non-relational databases(MongoDB). Sequelize supports non-relational databases (MSSQL, MYSQL, SQLLite).

Koa project construction

cnpm install -g koa-generator
// 这里一定要用koa2
koa2 /foo

Koa common middleware introduction

The application generated by koa-generator already contains common middleware , here I only talk about the ones that are not used in it.

koa-less

app.use(require('koa-less')(dirname + '/public'))

Must be used before static, otherwise it will be invalid.

Create new styles.less in the stylesheets folder and introduce all modular less files.

@import 'foo.less';
@import 'bar.less';

In this way, all styles will be compiled into a style.css. Just reference style.css in the template (pug).

koa-session

// 设置app keys，session会根据这个进行加密
app.keys = ['some secret hurr'];
// 配置session config
const CONFIG = {
  key: 'bougie:session',
  /** (string) cookie key (default is koa:sess) */
  maxAge: 1000 * 60 * 60 * 24 * 7,
  overwrite: true,
  /** (boolean) can overwrite or not (default true) */
  httpOnly: true,
  /** (boolean) httpOnly or not (default true) */
  signed: true,
  /** (boolean) signed or not (default true) */
  rolling: true,
  /** (boolean) Force a session identifier cookie to be set on every response. The expiration is reset to the original maxAge, resetting the expiration countdown. (default is false) */
  renew: false,
  /** (boolean) renew session when session is nearly expired, so we can always keep user logged in. (default is false)*/
};
// 应用中间件
app.use(session(CONFIG, app));

This must be used before the router, otherwise it will be invalid.

Basically used, can be used as a normal object

// 赋值
ctx.session.statu = value
// 取值
ctx.session.statu
// 删除
ctx.session.statu = null

koa-proxies

Used for proxy configuration

const proxy = require('koa-proxies')
app.use(proxy('/octocat', {
  target: 'https://api.github.com/users',  
  changeOrigin: true,
  agent: new httpsProxyAgent('http://1.2.3.4:88'),
  rewrite: path => path.replace(/^\/octocat(\/|\/\w+)?$/, '/vagusx'),
  logs: true
}))

Routing control

Development mainly focuses on routing control, including restful interface and template rendering

Getting parameters (request)

Query parameters (?param=a)

ctx.query.param

Routing parameters(/:id)

ctx.params.id

POST parameters (JSON or Form)

ctx.request.body

Request response(response)

The data the server responds to the client

restful

ctx.body = yourData

Template rendering

Default from Starting from the views directory, no file suffix is ​​allowed

ctx.render('layout', yourData)

Routing interception

Reject the request when not logged in, which will return 404

const userAuth = (ctx, next) => {
  let isLogin = ctx.session.isLogin
  if(isLogin) return next()
}
router.use('/', userAuth)

This operation will include In routes, such as "/a", "/b", etc., they need to be used before sub-routes, otherwise they will be invalid.

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to php Chinese website Other related articles!

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