微信小程序云开发怎样使用云函数生成二维码

// 云函数入口文件
const cloud = require('wx-server-sdk')
const rp = require('request-promise')

cloud.init()

// 云函数入口函数
exports.main = async (event, context) => {

 const page = event.page
 const scene = event.scene

 //appid和秘钥
 const appid = '***',
 secret = '***';

 const AccessToken_options = {
 method: 'GET',
 url: 'https://api.weixin.qq.com/cgi-bin/token',
 qs: {
 appid,
 secret,
 grant_type: 'client_credential'
 },
 json: true

 };

 //获取AccessToken
 const resultValue = await rp(AccessToken_options);
 const token = resultValue.access_token;

 //获取小程序码配置
 const code_options = {
 method: 'POST',
 url: 'https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=' + token,
 body: {
 'page': page,
 'width': 430,
 'scene': scene
 },
 json: true,
 encoding: null
 };

 //获取二进制图片
 const buffer = await rp(code_options);

 const upload = await cloud.uploadFile({
 cloudPath: 'wxacode.png',
 fileContent: buffer,
 })
 return {
 wxacodefileID: upload.fileID
 }

}