错误描述

用户登录微信小程序，初始登录会报错，接着再登录，就会登录成功。

后端catch住的异常

小程序

抛异常原因

小程序客户端调用微信服务器的接口顺序反了。
小程序客户端需要调用微信服务器的wx.login接口来获取code，然后调用wx.getUserInfo来获取加密数据和偏移向量iv。正确的顺序应该是先调用login，然后再调用getUserInfo。
而公司代码先调用了getUserInfo获取了解密数据，然后又调用的login，就会刷新登录态，这样获取的code换取的解密秘钥和提前获取的加密数据的加密秘钥就可能不一致的，所以无法成功解密。

错误代码

//先调用了getUserInfo,获取用户信息  bindGetUserInfo: function (e) {    //  console.log(e)    wx.showToast({      title: '加载中',      icon: 'loading',      duration: 3000    });    var that = this,      userInfo = e.detail,      encryptedData = userInfo.encryptedData,      iv = userInfo.iv;   //然后才调用了login    wx.login({      success: function (res) {        //用拿到的code，从后台获取sessionId        wx.request({          url: sessionID,          method: 'GET',          data: {            js_code: res.code,            movieCode: movieCode          },          header: {            "Content-Type": "application/x-www-form-urlencoded",            'Accept': 'application/json'          },        });     }  });

正确代码

//先调用loginwx.login({      success: function (res) {           //用拿到的code，从后台获取sessionId        wx.request({          url: sessionID,          method: 'GET',          data: {            js_code: res.code,            movieCode: movieCode          },          header: {            "Content-Type": "application/x-www-form-urlencoded",            'Accept': 'application/json'          },          success: function (res) {            // console.log('sessionId:');            // console.log(res.data.resultData);            // console.log(res.data.resultData);            var sessionId = res.data.resultData; //从后台获取到的sessionId            wx.setStorageSync('sessionId', sessionId);            //然后调用getUserInfo获取加密数据encryptedData和iv            wx.getUserInfo({              success: function(msg){                console.log(msg);                var encryptedData = msg.encryptedData,                 iv = msg.iv;                wx.request({                  url: userInfoUrl,                  method: 'POST',                  data: {                    encryptedData: encryptedData,                    iv: iv,                    sessionId: sessionId                  },         //代码不完整，参考者请注意。。。。