微信小程序在线客服自动回复功能(基于node)

<button open-type="contact">转在线客服</button>

  /*
   * https://developers.weixin.qq.com/miniprogram/dev/framework/server-ability/message-push.html
   * 验证消息的确来自微信服务器
   * 开发者通过检验 signature 对请求进行校验（下面有校验方式）。
   * 若确认此次 GET 请求来自微信服务器，请原样返回 echostr 参数内容，
   * 则接入生效，成为开发者成功，否则接入失败。加密/校验流程如下：
   * 将token、timestamp、nonce三个参数进行字典序排序
   * 将三个参数字符串拼接成一个字符串进行sha1加密
   * 开发者获得加密后的字符串可与signature对比，标识该请求来源于微信
   */
   const crypto = require('crypto');
   async wxCallbackAction(){
    const ctx = this.ctx;
    const method = ctx.method;
    //微信服务器签名验证，确认请求来自微信
    if(method === 'GET') {
      // 1.获取微信服务器Get请求的参数 signature、timestamp、nonce、echostr
      const {
        signature,
        timestamp,
        nonce,
        echostr
      } = ctx.query;
      
      // 2.将token、timestamp、nonce三个参数进行字典序排序
      let array = ['yourToken', timestamp, nonce];
      array.sort();
      
      // 3.将三个参数字符串拼接成一个字符串进行sha1加密
      const tempStr = array.join('');
      const hashCode = crypto.createHash('sha1'); //创建加密类型
      const resultCode = hashCode.update(tempStr, 'utf8').digest('hex');
      
      // 4.开发者获得加密后的字符串可与signature对比，标识该请求来源于微信
      if (resultCode === signature) {
        console.log('验证成功，消息是从微信服务器转发过来');
        return this.json(echostr);
      }else {
        console.log('验证失败！！！');
        return this.json({
          status: -1,
          message: "验证失败"
        });
      }
      
    }
   }

  const WXDecryptContact = require('./WXDecryptContact');
  async wxCallbackAction(){
    const ctx = this.ctx;
    const method = ctx.method;
    //接收信息时 为POST请求；(完整代码自行与上面验证时的合并即可)
    if(method === 'POST'){
      const { Encrypt } = ctx.request.body;
      //配置时选的安全模式 因此需要解密
      if(!Encrypt){
        return this.json('success');
      }
      const decryptData = WXDecryptContact(Encrypt);
      await this._handleWxMsg(decryptData);
      return this.json('success');
    }else{
      return this.json('success');
    }
  }
  
  //处理微信回调消息的总入口 (只处理了文本类型，其他类型自行添加)
  async _handleWxMsg(msgJson){
    if(!msgJson){
      return this.json('success');
    }

    const { MsgType } = msgJson;
    if(MsgType === 'text'){
      await this._sendTextMessage(msgJson);
    }
  }
  
  //微信文本信息关键字自动回复
  async _sendTextMessage(msgJson){
    //获取CMS客服关键词回复配置
    const result = await this.callService('cms.getDataByName', 'wxApplet.contact');
    
    let keyWordObj = result.data || {};
  
    //默认回复default
    let options = keyWordObj.default;
    for(let key in keyWordObj){
      //查看是否命中配置的关键词
      if(msgJson.Content === key){
        //CMS配置项
        options = keyWordObj[key];
        }
      }
    }
    
    //获取access_token
    const accessToken = await this._getAccessToken();
    
    /*
    * 先判断配置回复的消息类型是不是image类型
    * 如果是 则需要先通过 新增素材接口 上传图片文件获得 media_id
    */
    
    let media_id = '';
    if(options.type === 'image'){
      //获取图片地址(相对路径)
      let url = options.url;
      const file = fs.createReadStream(url);
      
      //调用微信 uploadTempMedia接口 具体实现见 service.js
      const mediaResult = await this.callService('wxApplet.uploadTempMedia',
        {
          access_token: accessToken,
          type: 'image'
        },
        {
          media: file
        }
      );
      
      if(mediaResult.status === 0){
        media_id = mediaResult.data.media_id;
      }else {
        //如果图片id获取失败 则按默认处理
        options = keyWordObj.default;
      }
    }
    
    //回复信息给用户
    const sendMsgResult = await this.callService('wxApplet.sendMessageToCustomer',
      {
        access_token: accessToken,
        touser: msgJson.FromUserName,
        msgtype: options.type || 'text',
        text: {
          content: options.description || '',
        },
        link: options.type === "link" ? 
          {
            title: options.title,
            description: options.description,
            url: options.url,
            thumb_url: options.thumb_url
          }
          :
          {},
        image: {
          media_id
        }
      }
    );    
  }

const request = require('request');
/*
* 获取CMS客服关键词回复配置
* 这个接口只是为了回去CMS配置的字段回复关键字配置 返回的data数据结构如下
*/
async contact(){
  return {
    data: {
      "1": {
        "type": "link",
        "title": "点击下载[****]APP",
        "description": "注册领取领***元注册红包礼",
        "url": "https://m.renrendai.com/mo/***.html",
        "thumb_url": "https://m.we.com/***/test.png"
       },
       "2": {
        "url": "http://m.renrendai.com/cms/****/test.jpg",
        "type": "image"
       },
       "3": {
        "url": "/cms/***/test02.png",
        "type": "image"
       },
       "default": {
        "type": "text",
        "description": "再见"
       }
    }
  }
}

/*
 * 把媒体文件上传到微信服务器。目前仅支持图片。用于发送客服消息或被动回复用户消息。
 * https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/customer-message/customerServiceMessage.uploadTempMedia.html
 */
 
 async uploadTempMedia(data,formData){
  const url = `https://api.weixin.qq.com/cgi-bin/media/upload?access_token=${data.access_token}&type=${data.type}`;
  return new Promise((resolve, reject) => {
    request.post({url, formData: formData}, (err, response, body) => {
      try{
        const out = JSON.parse(body);
        let result = {
          data: out,
          status: 0,
          message: "ok"
        }
        
        return resolve(result);
      
      }catch(err){
        return reject({
          status: -1,
          message: err.message
        });
      }
    });
  }
 }
 
 /*
 * 发送客服消息给用户
 * https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/customer-message/customerServiceMessage.send.html
 */
 
 async sendMessageToCustomer(data){
  const url = `https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=${data.access_token}`;
  return new Promise((resolve, reject) => {
    request.post({url, data}, (err, response, body) => {
      ...
    });
  }
 }

const crypto = require('crypto'); // 加密模块

const decodePKCS7 = function (buff) {
  let pad = buff[buff.length - 1];
  if (pad < 1 || pad > 32) {
    pad = 0;
  }
  return buff.slice(0, buff.length - pad);
};

// 微信转发客服消息解密
const decryptContact = (key, iv, crypted) => {
  const aesCipher = crypto.createDecipheriv('aes-256-cbc', key, iv);
  aesCipher.setAutoPadding(false);
  let decipheredBuff = Buffer.concat([aesCipher.update(crypted, 'base64'), aesCipher.final()]);
  decipheredBuff = decodePKCS7(decipheredBuff);
  const lenNetOrderCorpid = decipheredBuff.slice(16);
  const msgLen = lenNetOrderCorpid.slice(0, 4).readUInt32BE(0);
  const result = lenNetOrderCorpid.slice(4, msgLen   4).toString();
  return result;
};

// 解密微信返回给配置的消息服务器的信息
const decryptWXContact = (wechatData) => {
  if(!wechatData){
    wechatData = '';
  }
  //EncodingAESKey 为后台配置时随机生成的
  const key = Buffer.from(EncodingAESKey   '=', 'base64');
  const iv = key.slice(0, 16);
  const result = decryptContact(key, iv, wechatData);
  const decryptedResult = JSON.parse(result);
  console.log(decryptedResult);
  return decryptedResult;
};
module.exports = decryptWXContact;