知新 | koa框架入门到熟练第二章
koa-bodyparser 使用 这里对koa-bodyparser的使用教程。目录如下
ejs文件
ejs模板文件
[*] <!DOCTYPE html>
[*] <html lang="en">
[*] <head>
[*] <meta charset="UTF-8">
[*] <title>Title</title>
[*] </head>
[*] <body>
[*] <form action="/doAdd" method="post">
[*] 用户名: <input type="text" name="username"/>
[*] 密码: <input type="password" name="password"/>
[*] <button type="submit">提交</button>
[*] </form>
[*] </body>
[*] </html>
koa-bodyparser
使用koa-bodyparser获取body内容
[*] var koa = require("koa");
[*]
[*] var Router = require("koa-router");
[*]
[*] var bodyParser = require("koa-bodyparser");
[*]
[*] var app = new koa();
[*]
[*] var router = new Router();
[*]
[*] var views = require("koa-views");
[*]
[*] app.use(views("views", {
[*] extension: "ejs",
[*] }))
[*]
[*] app.use(bodyParser());
[*]
[*] // koa中间件
[*] app.use(async (ctx, next) => {
[*] console.log(new Date());
[*]
[*] await next();
[*] });
[*]
[*]
[*]
[*] router.get("/", async (ctx) => {
[*] await ctx.render("index");
[*] })
[*]
[*] router.post("/doAdd", async (ctx) => {
[*] console.log(ctx.request.body);
[*] ctx.body = ctx.request.body;
[*] })
[*] app.use(router.routes());
[*] app.use(router.allowedMethods());
[*]
[*]
[*] app.listen(3001);
使用效果
登录页面
koa-static 这里学习使用koa-static
安装
[*] PS C:\Users\Administrator\Desktop\untitled3> npm install --save koa-static
[*] npm WARN untitled3@1.0.0 No description
[*] npm WARN untitled3@1.0.0 No repository field.
[*]
[*] + koa-static@5.0.0
[*] added 1 package in 2.042s
[*]
[*] 2 packages are looking for funding
[*] run `npm fund` for details
[*]
[*] PS C:\Users\Administrator\Desktop\untitled3>
访问效果
访问效果如下
art-template 这里使用art-template 作为一个模板引擎使用
安装
[*] PS C:\Users\Administrator\Desktop\untitled3> npm install --save art-template
[*] npm WARN untitled3@1.0.0 No description
[*] npm WARN untitled3@1.0.0 No repository field.
[*]
[*] + art-template@4.13.2
[*] added 33 packages from 141 contributors in 6.704s
[*]
[*] 2 packages are looking for funding
[*] run `npm fund` for details
[*]
[*] PS C:\Users\Administrator\Desktop\untitled3> npm install --save koa-art-template
[*] npm WARN untitled3@1.0.0 No description
[*] npm WARN untitled3@1.0.0 No repository field.
[*]
[*] + koa-art-template@1.1.1
[*] added 2 packages from 4 contributors in 2.336s
[*]
[*] 2 packages are looking for funding
[*] run `npm fund` for details
代码如下
[*] var koa = require("koa");
[*]
[*] var Router = require("koa-router");
[*]
[*] var bodyParser = require("koa-bodyparser");
[*]
[*] var static = require("koa-static");
[*]
[*] var app = new koa();
[*]
[*] var router = new Router();
[*]
[*] var views = require("koa-views");
[*]
[*] var render = require("koa-art-template");
[*]
[*] var path = require("path");
[*]
[*] app.use(views("views", {
[*] extension: "ejs",
[*] }))
[*]
[*] app.use(static("./static"));
[*]
[*] app.use(bodyParser());
[*]
[*] // koa中间件
[*] app.use(async (ctx, next) => {
[*] console.log(new Date());
[*]
[*] await next();
[*] });
[*]
[*]
[*]
[*] router.get("/", async (ctx) => {
[*] await ctx.render("index");
[*] })
[*]
[*] router.post("/doAdd", async (ctx) => {
[*] console.log(ctx.request.body);
[*] ctx.body = ctx.request.body;
[*] })
[*]
[*] render(app, {
[*] root: path.join(__dirname, "views"),
[*] extname: ".art",
[*] })
[*]
[*] app.use(async function (ctx){
[*] await ctx.render("user");
[*] })
[*]
[*] app.use(router.routes());
[*] app.use(router.allowedMethods());
[*]
[*]
[*] app.listen(3001);
art 文件如下
[*] var koa = require("koa");
[*]
[*] var Router = require("koa-router");
[*]
[*] var bodyParser = require("koa-bodyparser");
[*]
[*] var static = require("koa-static");
[*]
[*] var app = new koa();
[*]
[*] var router = new Router();
[*]
[*] var views = require("koa-views");
[*]
[*] var render = require("koa-art-template");
[*]
[*] var path = require("path");
[*]
[*] app.use(views("views", {
[*] extension: "ejs",
[*] }))
[*]
[*] app.use(static("./static"));
[*]
[*] app.use(bodyParser());
[*]
[*] // koa中间件
[*] app.use(async (ctx, next) => {
[*] console.log(new Date());
[*]
[*] await next();
[*] });
[*]
[*]
[*]
[*] router.get("/", async (ctx) => {
[*] await ctx.render("index");
[*] })
[*]
[*] router.post("/doAdd", async (ctx) => {
[*] console.log(ctx.request.body);
[*] ctx.body = ctx.request.body;
[*] })
[*]
[*] render(app, {
[*] root: path.join(__dirname, "views"),
[*] extname: ".art",
[*] })
[*]
[*] app.use(async function (ctx){
[*] await ctx.render("user");
[*] })
[*]
[*] app.use(router.routes());
[*] app.use(router.allowedMethods());
[*]
[*]
[*] app.listen(3001);
访问效果
cookie
[*] var koa = require("koa");
[*]
[*] var Router = require("koa-router");
[*]
[*] var bodyParser = require("koa-bodyparser");
[*]
[*] var static = require("koa-static");
[*]
[*] var app = new koa();
[*]
[*] var router = new Router();
[*]
[*] var views = require("koa-views");
[*]
[*] var render = require("koa-art-template");
[*]
[*] var path = require("path");
[*]
[*]
[*] app.use(bodyParser());
[*]
[*] // koa中间件
[*] app.use(async (ctx, next) => {
[*] console.log(new Date());
[*]
[*] await next();
[*] });
[*]
[*] router.get("/", async (ctx) => {
[*] ctx.cookies.set("ming", "ming")
[*] })
[*] app.use(router.routes());
[*] app.use(router.allowedMethods());
[*]
[*]
[*] app.listen(3001);
koa-session
[*] PS C:\Users\Administrator\Desktop\untitled3> npm install koa-session
[*] npm WARN untitled3@1.0.0 No description
[*] npm WARN untitled3@1.0.0 No repository field.
[*]
[*] + koa-session@6.0.0
[*] added 10 packages from 14 contributors in 3.484s
[*]
[*] 2 packages are looking for funding
[*] run `npm fund` for details
[*]
[*] PS C:\Users\Administrator\Desktop\untitled3>
编写一个简单的刷新页面次数增加
[*] var koa = require("koa");
[*]
[*] var Router = require("koa-router");
[*]
[*] var bodyParser = require("koa-bodyparser");
[*]
[*] var static = require("koa-static");
[*]
[*] var app = new koa();
[*]
[*] var router = new Router();
[*]
[*] var views = require("koa-views");
[*]
[*] var render = require("koa-art-template");
[*]
[*] var path = require("path");
[*]
[*] var session = require("koa-session");
[*]
[*] app.keys = ['secret']; // session加密字段
[*]
[*] app.use(session({
[*] key: 'koa:sess', //cookie key (default is koa:sess)
[*] maxAge: 86400000, // cookie的过期时间 maxAge in ms (default is 1 days)
[*] overwrite: true, //是否可以overwrite (默认default true)
[*] httpOnly: true, //cookie是否只有服务器端可以访问 httpOnly or not (default true)
[*] signed: true, //签名默认true
[*] rolling: false, //在每次请求时强行设置cookie，这将重置cookie过期时间（默认：false）
[*] renew: false, //(boolean) renew session when session is nearly expired,
[*] }, app));
[*]
[*] app.use(bodyParser());
[*]
[*] // koa中间件
[*] app.use(async (ctx, next) => {
[*] console.log(new Date());
[*]
[*] await next();
[*] });
[*]
[*]
[*] app.use(ctx => {
[*] // ignore favicon
[*] if (ctx.path === '/favicon.ico') return
[*] console.log(ctx.session)
[*] let n = ctx.session.views || 0
[*] ctx.session.views = ++n
[*] ctx.body = n + ' views'
[*] });
[*]
[*]
[*] router.get("/", async (ctx) => {
[*] ctx.cookies.set("ming", "ming")
[*] })
[*]
[*] app.use(router.routes());
[*] app.use(router.allowedMethods());
[*]
[*]
[*] app.listen(3001);
原型链继承
[*] // 构造原型
[*] function Person(name, age) {
[*] this.name = name;
[*] this.age = 333;
[*] this.run = function () {
[*] console.log(this.name, this.age)
[*] }
[*] }
[*]
[*] // 添加work方法，在原型链上继承
[*] Person.prototype.work = () => {
[*] console.log("work");
[*] }
[*]
[*] function Web() {
[*]
[*] }
[*]
[*] // 同样继承
[*] Web.prototype = new Person();
[*]
[*] var w = new Web();
[*] // 以下两个运行原型链的值
[*] w.run();
[*] w.work()
静态方法和构造方法
[*] // 新建类
[*] class Person{
[*] constructor(name) {
[*] this._name = name;
[*] }
[*] run(){
[*] console.log(this._name);
[*] }
[*] // 静态方法
[*] static work(){
[*] console.log("静态方法");
[*] }
[*] }
[*]
[*] Person.work();
koa 操作mongoDB 安装相关的库
[*] PS C:\Users\Administrator\Desktop\untitled3> npm install mongodb --save
[*] npm WARN untitled3@1.0.0 No description
[*] npm WARN untitled3@1.0.0 No repository field.
[*]
[*] + mongodb@3.5.9
[*] updated 1 package in 2.854s
[*]
[*] 2 packages are looking for funding
[*] run `npm fund` for details
[*]
[*] PS C:\Users\Administrator\Desktop\untitled3>
增加一条数据
[*] var MongoClient = require("mongodb").MongoClient;
[*]
[*] var dbUrl = 'mongodb://106.53.115.12:27017/'
[*]
[*] var dbName = "koa";
[*]
[*] // 连接
[*] MongoClient.connect(dbUrl, (err, client) => {
[*] if(err){
[*] console.log(err);
[*] return;
[*] }
[*]
[*] var db = client.db(dbName);
[*]
[*] // 增加数据
[*] db.collection("user").insertOne({
[*] "username":"xiaoxiao","age":"23"
[*] });
[*]
[*] })
结果：
对返回结果进行处理
[*] var MongoClient = require("mongodb").MongoClient;
[*]
[*] var dbUrl = 'mongodb://106.53.115.12:27017/'
[*]
[*] var dbName = "koa";
[*]
[*] // 连接
[*] MongoClient.connect(dbUrl, (err, client) => {
[*] if(err){
[*] console.log(err);
[*] return;
[*] }
[*]
[*] var db = client.db(dbName);
[*]
[*] // 增加数据
[*] db.collection("user").insertOne({
[*] "username":"xiaoxiao","age":"23"
[*] }, function (err, result) {
[*] if(!err){
[*] console.log("增加数据成功 ");
[*] client.close();
[*] console.timeEnd("start");
[*] }
[*] });
[*]
[*] })
查询数据
代码如下
[*] var MongoClient = require("mongodb").MongoClient;
[*]
[*] var dbUrl = 'mongodb://106.53.115.12:27017/'
[*]
[*] var dbName = "koa";
[*]
[*] // 连接
[*] MongoClient.connect(dbUrl, (err, client) => {
[*] if(err){
[*] console.log(err);
[*] return;
[*] }
[*]
[*] var db = client.db(dbName);
[*]
[*] var result = db.collection("user").find(0);
[*]
[*] result.toArray((err, docs) => {
[*] console.log(docs);
[*] })
[*]
[*] })
输出内容如下
[*] "C:\Program Files\nodejs\node.exe" C:\Users\Administrator\Desktop\untitled3\01es6.js
[*] (node:15216) DeprecationWarning: current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
[*] [
[*] { _id: 5f0fe666bc0d9e41101dffd3, username: 'xiaoxiao', age: '23' },
[*] { _id: 5f0fe7f4949f1b420c120fe7, username: 'xiaoxiao', age: '23' }
[*] ]
koa 应用生成器
全局安装
使用全局安装koa的脚手架
[*] PS C:\Users\Administrator\Desktop\untitled3> npm install koa-generator -g
[*] npm WARN deprecated mkdirp@0.5.1: Legacy versions of mkdirp are no longer supported. Please update to mkdirp 1.x. (Note that the API surface has changed to use Promises in 1.x.)
[*] C:\Users\Administrator\AppData\Roaming\npm\koa -> C:\Users\Administrator\AppData\Roaming\npm\node_modules\koa-generator\bin\koa
[*] C:\Users\Administrator\AppData\Roaming\npm\koa2 -> C:\Users\Administrator\AppData\Roaming\npm\node_modules\koa-generator\bin\koa2
[*] + koa-generator@1.1.17
[*] updated 1 package in 0.905s
[*] PS C:\Users\Administrator\Desktop\untitled3>
创建项目
[*] PS C:\Users\Administrator\Desktop> ls
[*]
[*]
[*] 目录: C:\Users\Administrator\Desktop
[*]
[*]
[*] Mode LastWriteTime Length Name
[*] ---- ------------- ------ ----
[*] d----- 2020/7/14 17:08 insurv-mina-node-api
[*] d----- 2020/7/14 17:45 koa
[*] d----- 2020/7/14 17:55 untitled
[*] d----- 2020/7/16 14:16 untitled3
[*] -a---- 2020/7/16 12:04 5782870 Navicat Premium 15.x最新注册机.zip
[*] -a---- 2020/7/14 17:07 1428 Visual Studio Code.lnk
[*] -a---- 2019/11/30 18:03 1526 WPS 2019.lnk
[*] -a---- 2020/7/14 18:52 1064 百度网盘.lnk
[*]
[*]
[*] PS C:\Users\Administrator\Desktop> mkdir ./ming
[*]
[*]
[*] 目录: C:\Users\Administrator\Desktop
[*]
[*]
[*] Mode LastWriteTime Length Name
[*] ---- ------------- ------ ----
[*] d----- 2020/7/16 14:19 ming
[*]
[*]
[*] PS C:\Users\Administrator\Desktop> ls
[*]
[*]
[*] 目录: C:\Users\Administrator\Desktop
[*]
[*]
[*] Mode LastWriteTime Length Name
[*] ---- ------------- ------ ----
[*] d----- 2020/7/14 17:08 insurv-mina-node-api
[*] d----- 2020/7/14 17:45 koa
[*] d----- 2020/7/16 14:19 ming
[*] d----- 2020/7/14 17:55 untitled
[*] d----- 2020/7/16 14:16 untitled3
[*] -a---- 2020/7/16 12:04 5782870 Navicat Premium 15.x最新注册机.zip
[*] -a---- 2020/7/14 17:07 1428 Visual Studio Code.lnk
[*] -a---- 2019/11/30 18:03 1526 WPS 2019.lnk
[*] -a---- 2020/7/14 18:52 1064 百度网盘.lnk
[*]
[*]
[*] PS C:\Users\Administrator\Desktop> cd ./ming
[*] PS C:\Users\Administrator\Desktop\ming> ls
[*] PS C:\Users\Administrator\Desktop\ming> koa koa_demo
[*]
[*] create : koa_demo
[*] create : koa_demo/package.json
[*] create : koa_demo/app.js
[*] create : koa_demo/public
[*] create : koa_demo/routes
[*] create : koa_demo/routes/index.js
[*] create : koa_demo/routes/users.js
[*] create : koa_demo/public/javascripts
[*] create : koa_demo/views
[*] create : koa_demo/views/index.jade
[*] create : koa_demo/views/layout.jade
[*] create : koa_demo/views/error.jade
[*] create : koa_demo/public/images
[*] create : koa_demo/public/stylesheets
[*] create : koa_demo/public/stylesheets/style.css
[*] create : koa_demo/bin
[*] create : koa_demo/bin/www
[*]
[*] install dependencies:
[*] > cd koa_demo && npm install
[*]
[*] run the app:
[*] > SET DEBUG=koa_demo:* & npm start
[*]
[*] PS C:\Users\Administrator\Desktop\ming> ls
[*]
[*]
[*] 目录: C:\Users\Administrator\Desktop\ming
[*]
[*]
[*] Mode LastWriteTime Length Name
[*] ---- ------------- ------ ----
[*] d----- 2020/7/16 14:19 koa_demo
[*]
[*]
[*] PS C:\Users\Administrator\Desktop\ming> cd ./koa_demo
[*] PS C:\Users\Administrator\Desktop\ming\koa_demo>
此时脚手架已经安装成功
安装依赖
[*] PS C:\Users\Administrator\Desktop\ming\koa_demo> npm install
[*] npm WARN deprecated chokidar@2.1.8: Chokidar 2 will break on node v14+. Upgrade to chokidar 3 with 15x less dependencies.
[*] npm WARN deprecated swig@1.4.2: This package is no longer maintained
[*] npm WARN deprecated jade@1.11.0: Jade has been renamed to pug, please install the latest version of pug instead of jade
[*] npm WARN deprecated constantinople@3.0.2: Please update to at least constantinople 3.1.1
[*] npm WARN deprecated transformers@2.1.0: Deprecated, use jstransformer
[*] npm WARN deprecated native-or-bluebird@1.2.0: 'native-or-bluebird' is deprecated. Please use 'any-promise' instead.
[*]
[*] > nodemon@1.19.4 postinstall C:\Users\Administrator\Desktop\ming\koa_demo\node_modules\nodemon
[*] > node bin/postinstall || exit 0
[*]
[*] npm notice created a lockfile as package-lock.json. You should commit this file.
[*] npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.13 (node_modules\fsevents):
[*] npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
[*]
[*] added 367 packages from 208 contributors in 21.748s
[*]
[*] 1 package is looking for funding
[*] run `npm fund` for details
[*]
[*] PS C:\Users\Administrator\Desktop\ming\koa_demo>
启动项目
[*] npm start
小明菜市场
文档来源：51CTO技术博客https://blog.51cto.com/u_14032861/2989732
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