nodejs怎么自动回复

const http = require("http");const url = require("url");const crypto = require("crypto");const express = require("express");const wechat = require("wechat");const token = "your token here";  // 设置tokenconst appid = "your appid here";  // 设置appIDconst appsecret = "your appsecret here";  // 设置appsecretconst port = 80;  // 设置端口const hostname = "your hostname here";  // 设置服务器名// 对token、timestamp和nonce进行字典序排序并进行sha1加密function sha1(str){    const hash = crypto.createHash("sha1");    hash.update(str);    return hash.digest("hex");}// 微信接入验证function wxVerify(req, res){    const query = url.parse(req.url, true).query;    const signature = query.signature;    const timestamp = query.timestamp;    const nonce = query.nonce;    const echostr = query.echostr;    const str = [token, timestamp, nonce].sort().join("");    if (signature === sha1(str)){        res.send(echostr);    } else {        res.send("error");    }}// 微信动作处理const wxFun = function(req, res){    const info = req.weixin;    console.log(info);    res.reply("这是自动回复的内容");  // 发送自动回复内容}const app = express();app.use("/wx", wechat({    token: token,    appid: appid,    appsecret: appsecret,    encodingAESKey: "", // 推荐使用的配置项    checkSignature: false,    // 微信接入验证    verify: wxVerify,    // 处理微信消息的回调函数    message: wxFun}))app.listen(port, hostname);console.log("Server running at http://" + hostname + ":" + port);