接口设计

let http = require('http');
let url = require('url');
let querystring = require('querystring');
let fs = require('fs');
let user = {
    admin: 123456
}
http.createServer((req, res) => {
    let path, get, post
    if (req.method == 'GET') {
        let { pathname, query } = url.parse(req.url, true);
        path = pathname;
        get = query;
        complete();
    } else if (req.method == 'POST') { 
        let arr = [];
        path = req.url;
        req.on('data', buffer => {
            arr.push(buffer)
        });
        req.on("end", () => {
            post = querystring.parse(Buffer.concat(arr).toString());
            complete();
        })
    }
    function complete() {
        if (path == '/login') {
            res.writeHead(200, {
                'Content-Type': 'text/plain;charset=utf-8'
            })
            let { username, password } = get;
            if (!user[username]) {
                res.end(JSON.stringify({
                    err: 1,
                    msg: '用户名不存在'
                }))
            } else if (user[username] != password) {
                res.writeHead(200, {
                    'Content-Type': 'text/plain;charset=utf-8'
                })
                res.end(JSON.stringify({
                    err: 1,
                    msg: '密码不正确'
                }))
            } else {
                res.end(JSON.stringify({
                    err: 0,
                    msg: '登陆成功'
                }))
            }
        } else if (path == '/reg') {
            res.writeHead(200, {
                'Content-Type': 'text/plain;charset=utf-8'
            });
            let { username, password } = post;
            if (user[username]) {
                res.end(JSON.stringify({
                    err: 1,
                    msg: '用户已经存在'
                }))
            } else {
                user[username] = password;
                res.end(JSON.stringify({
                    err: 0,
                    msg: '注册成功'
                }))
            }
        } else {
            fs.readFile(`www${path}`,(err,data)=> {
                if(err){
                    res.end('404');
                }else{
                    res.end(data);
                }
            })
        }
    }
}).listen(8080)