Introduction: To implement a KOA service startup, followed by mock data links to the project, local code debugging, to achieve fast page effect, front-end and back-end coordination

1. Download the KOA package

npm install -D koa
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The main implementation of the use of the core method: using the Node OS module, find the specific network address, local service forwarding of the project

var os = require("os");
// Returns an object containing the network interface for which the network address has been assigned
var ifaces = os.networkInterfaces(); 
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/* * @title: using Koa to build Node services * @description: description */

const Koa = require("koa");
const router = require("koa-router") ();// Introduces koA-BodyParser middleware, which returns THE parameters of post requests in JSON format
const bodyParser = require('koa-bodyparser');
// With the middleware, we can use ctx.request.body to get the POST request parameters, which the middleware automatically interprets as JSON

var os = require("os");
// Returns an object containing the network interface for which the network address has been assigned
var ifaces = os.networkInterfaces(); 

const PORT = 8008;
let ipAddress = "0.0.0.0";
// Get the object address
Object.keys(ifaces).forEach(function(ifname) {
    var alias = 0;
    ifaces[ifname].forEach(function(iface) {
        if ("IPv4"! == iface.family || iface.internal ! = =false) {
            Skip over internal (i.e. 127.0.0.1) and non-ipv4 addresses
            return;
        }
        if (alias >= 1) {
            // this single interface has multiple ipv4 addresses
            // console.log(ifname + ":" + alias, iface.address);
            ipAddress = iface.address;
        } else {
            // this interface has only one ipv4 adress
            // console.log(ifname, iface.address);
            ipAddress = iface.address;
        }
        ++alias;
    });
});
console.log("ipAddress",ipAddress);

// Create a server
const app = new Koa();
app.use(bodyParser());
app.use(async (ctx, next) => {
  ctx.set("Access-Control-Allow-Origin"."*");  // Specifies the outer domain URI that allows access to the resource

  console.log(` service${ctx.request.method} ${ctx.request.url}. `);
  await next();
});
router.get("/".async (ctx, next) => {
  ctx.response.body = {
    a: 1.b: "123"}; });/ / redirection
router
    .all("/".(ctx, next) = > {
        const url = `http://${ipAddress}:${PORT}/api/queryNumList`;
        ctx.body = <a href=" <a href="${url}" target="_blank">${url}</a> </p> <p>please check your url!!! </p> `;
    })

/ / case
router.get('/api/employees'.async (ctx,  next)  => {
    ctx.response.body = {
    status:true.data:[
        { projecttype: "Project Order Implementation".totalCount: "26" },
        { projecttype: "Before".totalCount: "2" },
        { projecttype: "Project Order Implementation".totalCount: "2" },
        { projecttype: "Post evaluation".totalCount: "23" },
        { projecttype: "Project Order Implementation".totalCount: "26" },
        { projecttype: "Operations".totalCount: "62" },
        { projecttype: "Trial run".totalCount: "2"}].msg:'Data obtained successfully'}}); app.use(router.routes()).use(router.allowedMethods()); app.listen(9000.() = > {
  console.log(The node service has started. Please visit localhost:9000);
});

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