var requestp = require('request-promise');var fs = require('fs'); // 載入fs模塊

var wxapi = {};module.exports = wxapi;//獲取二維碼wxapi.qrcode = async (ctx, next) => {  //獲取access_token  var access_token = global.access_token  var qrcodeurl = 'https://api.weixin.qq.com/wxa/getwxacode?access_token='+access_token  let options = {    method: 'POST',    uri: qrcodeurl,    encoding:null,    body: {      "path": 'pages/index/index?openid='+ctx.query.openid,//帶參數的path      "width":280,      "is_hyaline":false    },    json: true  }  var imgname='./public/images/'+ ctx.query.openid+'.jpg'  var imgnameback=ctx.query.openid+'.jpg'  fs.exists(imgname, function (exists) {    //判斷圖片是否存在    if(!exists){      //通過微信接口獲取小程序碼      requestp(options)      .then(function (body) {         var base64Img = body.toString('base64'); // base64圖片編碼字符串        var dataBuffer = new Buffer(base64Img, 'base64');        //保存到本地        fs.writeFile(imgname, dataBuffer, function(err) {          if(err){            console.log(err);          }else{            console.log("保存成功！");          }        });      })      .catch(function (err) {        console.log(err)      });    }  })  //返回圖片名  ctx.body = {    code: 1,    img: imgnameback  }};