md5 uid

 import axios from 'axios';
+import md5 from 'md5';
 
 export default class reportApp {
   constructor(params = {}) {
@@ -9,7 +10,7 @@ export default class reportApp {
       ab: params.buildId,
       ca: '0',
       net: 'unknown',
-      sid: params.visitId,
+      sid: md5(`${params.udid}_${new Date().getTime()}`)
     };
     this.params = {
       mst: '',
@@ -62,7 +63,7 @@ export default class reportApp {
         device: this.device,
         events: [
           Object.assign({
-            uid: uid,
+            uid: md5(uid),
             ts: new Date().getTime() + '000000',
             pt: pt,
             pn: pn,

@@ -48,8 +48,7 @@ const getContext = (req) => {
       clientIp: req.yoho.clientIp,
       version: req.query.app_version || pkg.version,
       osVersion: req.query.os_version || '',
-      buildId: req.app.locals.buildId,
-      visitId: md5(`${req.yoho.udid}_${new Date().getTime()}`)
+      buildId: req.app.locals.buildId
     },
     ua: req.get('user-agent'),
     hostname: os.hostname(),