摘要：路由封裝了和變量傳入將要處理的下一個(gè)異步函數(shù)由標(biāo)記的函數(shù)稱(chēng)為異步函數(shù)，在異步函數(shù)中，可以用調(diào)用另一個(gè)異步函數(shù)，這兩個(gè)關(guān)鍵字將在中引入。

const router = require("koa-router")()

ctx：封裝了request 和 response變量

next: 傳入將要處理的下一個(gè)異步函數(shù)

由async標(biāo)記的函數(shù)稱(chēng)為異步函數(shù)，在異步函數(shù)中，可以用await調(diào)用另一個(gè)異步函數(shù)，這兩個(gè)關(guān)鍵字將在ES7中引入。

${ctx.request.url} 輸出 請(qǐng)求的url 地址 ctx.url相當(dāng)于ctx.request.url，ctx.type相當(dāng)于ctx.response.type

處理路由器的操作分為：views、 string、 json、 處理get請(qǐng)求、 處理post請(qǐng)求

router.get("/", async (ctx, next) => {
  await ctx.render("index", {
    title: "Hello Koa 2!"
  })
})

router.get("/string",async (ctx, next) =>{ 
    ctx.response.body = `
welcome, hello
`;
})

router.get("/json", async (ctx, next) => {
  ctx.body = {
    title: "koa2 json"
  }
})

var name = ctx.params.name;

router.get("/info/:name", async (ctx, next) => {
  var name = ctx.params.name;
  ctx.response.body = `
Hello, ${name}!
`;
})

var name = ctx.request.body.name || "";

需要引入 koa-bodyparser 中間件, 創(chuàng)建 info.pug 用于處理表單

extends layout

block content
  h1= title
  form(action="/signin" method="post")
    p= "用戶(hù)名："
    input(type="text" name="name" value="koa")
    p= "密碼："
    input(type="password" name="password" value="koa")
    p
    input(type="submit" value="提交")

router.get("/info", async (ctx, next) => {
  await ctx.render("info",{
    title: "用戶(hù)信息"
  });
})
// 處理post請(qǐng)求
router.post("/signin", async (ctx,next) => {
  var name = ctx.request.body.name || "";
  var password = ctx.request.body.password || "";
  if(name === "koa" && password === "koa") {
    ctx.response.body = `
welcome, ${name}
`;
  }else{
    ctx.response.body = `
Login faild!
    
Login
    `
  }
})

適用于 koa 的模板引擎選擇非常多，比如 jade、ejs、nunjucks、handlebars 、xtemplate 等。

Nunjucks是Mozilla開(kāi)發(fā)的一個(gè)純JavaScript編寫(xiě)的模板引擎 koa-nunjucks-2^3.0.2

https://mozilla.github.io/nun...

const koaNunjucks = require("koa-nunjucks-2")
app.use(koaNunjucks({
  ext: "html",
  path: path.join(__dirname, "views"),
  nunjucksConfig: {
    trimBlocks: true,
    noCache: false // 開(kāi)發(fā)環(huán)境下
  }
}));

// 模塊
{% extends "base.html" %}
{% block body %} 
No body
 {% endblock %}

// 循環(huán)
{% for msg in data %}
  
{{ msg }}
{% endfor %}

{% if hungry %}
  I am hungry
{% elif tired %}
  I am tired
{% else %}
  I am good!
{% endif %}

koa提供了從上下文直接讀取、寫(xiě)入cookie的方法:

ctx.cookies.get(name, [options]) 讀取上下文請(qǐng)求中的cookie

ctx.cookies.set(name, value, [options]) 在上下文中寫(xiě)入cookie

// 處理cookie
router.get("/cookie", async (ctx,next) => {
  const options = {
    domain:"127.0.0.1",
    path:"/",
    maxAge: 10 * 60 * 1000, // cookie有效時(shí)長(zhǎng)
    expires: new Date("2019-02-02"),  // cookie失效時(shí)間
    httpOnly: false,  // 是否只用于http請(qǐng)求中獲取
    overwrite: false  // 是否允許重寫(xiě)
  }
  ctx.cookies.set("id","test cookie",options)

  ctx.response.body = `
cookies, ${ctx.cookies.get("id")}
`; // 輸出cookie值
})

將session存放在MySQL數(shù)據(jù)庫(kù)中 koa-session-minimal、koa-mysql-session "koa-session-minimal":"^3.0.4","koa-mysql-session":"^0.0.2"

const session = require("koa-session-minimal")
const MysqlSession = require("koa-mysql-session")

// 配置存儲(chǔ)session
let store = new MysqlSession({
  user: "root",
  password: "",
  database: "test",
  host: "127.0.0.1",
})
let cookie = {
  maxAge: "", // cookie有效時(shí)長(zhǎng)
  expires: "",  // cookie失效時(shí)間
  path: "", // 寫(xiě)cookie所在的路徑
  domain: "", // 寫(xiě)cookie所在的域名
  httpOnly: "", // 是否只用于http請(qǐng)求中獲取
  overwrite: "",  // 是否允許重寫(xiě)
  secure: "",
  sameSite: "",
  signed: "",
  
}
app.use(session({
  key: "SESSION_ID",
  store: store,
  cookie: cookie
}))

// 處理session
router.get("/session", async (ctx,next) => {
  ctx.session = {
    user_id: Math.random().toString(36).substr(2),
    count: 0
  }
  ctx.response.body = `
session, ${ctx.session.user_id}, ${ctx.session.count}
`; // 輸出cookie值
})

安裝 mysql "mysql":"^2.15.0"

用戶(hù)增、刪、改、查

// 查詢(xún)
async function queryAll(){
    let sql = usersMapping.queryAll;
    let UsersList = await dbUtils(sql);
    return UsersList;
}
// 新增
async function insertUser(username,password,realname){
    let sql = usersMapping.insertUser;
    var values = [username,password,realname]; // 數(shù)組
    let result = await dbUtils(sql,values);
    if ( Array.isArray(result) && result.length > 0 ) {
        result = result[0]
    } else {
        result = null
    }
    return result
}
// 修改
async function queryById(id){
    let sql = usersMapping.queryById;
    let result = await dbUtils(sql,id);
    if ( Array.isArray(result) && result.length > 0 ) {
        result = result[0]
    } else {
        result = null
    }
    return result
}
async function updateUser(id,username,password,realname){
    // 從session中取 id
    let sql = usersMapping.updateUser;
    var values = [username,password,realname,id]; // 數(shù)組
    let result = await dbUtils(sql,values);
    if ( Array.isArray(result) && result.length > 0 ) {
        result = result[0]
    } else {
        result = null
    }
    return result
}
// 刪除
async function deleteById(id){
    let sql = usersMapping.deleteById;
    let flag = await dbUtils(sql,id);
    return flag;
}

github:

https://github.com/lichuang44...