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"Node learning notes" koa framework learning

2022-07-28 11:23:00 【51CTO】

Preface

Koa Is based on Node.js The next generation of the platform web Development framework , Many references are introductions Koa and Express The similarities and differences between them as well as simple comparisons .

Because of the previous study Express Mainly because it needs to pass Express Code the server , So the editor in this issue also tries to use Koa Code the server , have a look Koa How it works .

koa Address ： https://koa.bootcss.com/

One 、 introduce koa

       
       const Koa = require("koa");
       
const app = new Koa();
      
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Two 、 Incoming routing koa-router

The routing name is generally required to write the server ,koa-router It can help you map the defined route at one time .

       
       const router = require("koa-router")();
       
app.use(router.routes())         //  Start routing 
      
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3、 ... and 、 introduce cors

cors yes koa A package that handles cross domain requests , Only one reference is needed to handle cross domain .

       
       const cors = require("@koa/cors");
       
app.use(cors())
      
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Four 、 Write a request

1. get request

       
       // http://localhost:8080/news
       
router.get("/news", async ctx => {
       
   console.log(ctx.query);       //  Request parameters 
       
});
       
// http://localhost:8080/news2/aaa
       
router.get("/news2/:id", async ctx => {
       
   console.log(ctx.params);   // {id:'aaa'}
       
});
      
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2. post request

post The request to obtain the request parameters needs to pass koa-bodyparser Module to get .

       
       const bodyparser = require(“koa-bodyparser”)
       
app.use(bodyparser());
       
// http://localhost:8080/news3
       
router.post("/news3", async ctx => {
       
   let data = await ctx.request.body
       
});
      
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5、 ... and 、ctx Parameters

ctx.body： For callback parameters
ctx.type： Callback type
ctx.success： Successful callback , You need to define a function yourself and execute
ctx.fail： Failed callback , You need to define a function yourself and execute
ctx.status： Status code

That's what this issue is about Koa Frame learning Small share of , I hope I can help you .

In the next issue, I'll share more details about the actual combat , If you're interested in that , Welcome to pay attention to 、 Leaving a message. , Your support is my motivation ！

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