匹配任意文件和处理不存在的文件

import * as http from "http";
import {IncomingMessage, ServerResponse} from "http";
import * as p from 'path';
import * as fs from "fs";
import * as url from "url";

const server = http.createServer();
const publicDir = p.resolve(__dirname, 'public');  // __dirname表示当前文件所在目录

server.on('request', (request: IncomingMessage, response: ServerResponse) => {
    const {method, url: path, headers} = request
    const {pathname, search} = url.parse(path)
    // response.setHeader('Content-Type', 'text/html; charset=utf-8')
    let fileName = pathname.substr(1)  //  /index.html => index.html
    if (fileName === '') {
        fileName = 'index.html'
    }
    fs.readFile(p.resolve(publicDir, fileName), (error, data) => {
        if (error) {
            if (error.errno === -4058) {
                response.statusCode = 404
                fs.readFile(p.resolve(publicDir, '404.html'), (error,data)=> {
                    response.end(data)
                })
            } else if (error.errno === -4068) {
                response.statusCode = 403
                response.end('无权查看目录内容')
            } else {
                response.statusCode = 500;
                response.end('服务器繁忙，请稍后再试')
            }
        } else {
            response.end(data)
        }
    })
})

server.listen(8888)