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
