Front-end Towards Architect Step 1 – Quick understanding of the KOA Framework -2

I will continue to study the KOA framework today (~ ▽ ~).”

This article introduces some of the plug-ins commonly used for KOA:

• @koa/corsCross domain processing
• koa-bodyProtocol processing

Use koa-body and @KOA/CORS

• koa-bodyProcess data from requests
• @koa/corsHandle some cross-domain requests

NPM install -s koa-body@koa /cors

Note: You need to first use koa-body to process the data in the incoming request, and then use @koA/Cors to process some cross-domain requests

Get the post value in Koa

var Koa = require('koa');
var Router = require('koa-router');
var cors = require('@koa/cors');
var koabody = require('koa-body');
 
var app = new Koa();
var router = new Router();
 
router.post('/post'.async (ctx, next) => {
    let {body}=ctx.request;// Get the value given by the front end
    ctx.body={// Return the contents of the body to the front end. body } });//app.use pay attention to the order
app.use(koaBody())// Process the data from the request
app.use(cors())// Handle some cross-domain requests
 
app.use(router.routes())
    .use(router.allowedMethods());
 
app.listen(3000);
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Get and get get values in Koa

1. Key/value pair concatenation and parameter transmission. The received parameters are mainly obtained through ctx.qruery. It should be noted that the same result can be obtained in CTX and CTX.

2. Parameters are transmitted through dynamic routes. The received parameters are obtained through ctx.params.

The following is an example of key-value pair concatenation:

var Koa = require('koa');
var router = require('koa-router') ();var app = new Koa();
// http://localhost:3000/details? id=1&name=jiangyx
router.get('/details'.async(ctx)=>{
    // Read the Get pass from CTX
    console.log(ctx.url);// /details? id=1&name=jiangyx
    console.log(ctx.query); // {id: '1', name: 'jiangyx'
    console.log(ctx.querystring) // id=1&name=jiangyx //
 
    // Get the Get from the request in CTX
    console.log(ctx.request.url); // /details? id=1&name=jiangyx
    console.log(ctx.request.query); // { id: '1', name: 'jiangyx' }
    console.log(ctx.request.querystring); // id=1&name=jiangyx
});
 
app.use(router.routes());
app.use(router.allowedMethods());
app.listen(3000);
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The following is an example of dynamic route parameter transmission:

var Koa = require('koa');
var router = require('koa-router') ();var app = new Koa();
 
// http://localhost:3000/details/1/jiangyx
router.get('/details/:id/:name'.async (ctx) => {
    // Get the value of the dynamic route
    console.log(ctx.params); // { id: '1' ,name:'jiangyx'}
});
 
app.use(router.routes());
app.use(router.allowedMethods());
app.listen(3000);
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