diff --git a/lib/requestHandler/UserReqHandler.js b/lib/requestHandler/UserReqHandler.js
index 87b211d..cdff75b 100644
--- a/lib/requestHandler/UserReqHandler.js
+++ b/lib/requestHandler/UserReqHandler.js
@@ -1,3 +1,7 @@
+/// <reference path="../../typings/index.d.ts" />
+
+import RequestErrorHandler from './requestErrorHandler';
+
 const
   url = require('url'),
   https = require('https'),
@@ -12,8 +16,7 @@ const
   brotliTorb = require('brotli'),
   co = require('co');
 
-const requestErrorHandler = require('./requestErrorHandler');
-
+const requestErrorHandler = new RequestErrorHandler();
 const DEFAULT_CHUNK_COLLECT_THRESHOLD = 20 * 1024 * 1024; // about 20 mb
 
 // to fix issue with TLS cache, refer to: https://github.com/nodejs/node/issues/8368
@@ -203,7 +206,7 @@ export default class UserReqHandler {
       in http  server: http://www.example.com/a/b/c
       in https server: /a/b/c
     */
-
+    const self = this;
     const host = req.headers.host;
     const protocol = (!!req.connection.encrypted && !(/^http:/).test(req.url)) ? 'https' : 'http';
     const fullUrl = protocol === 'http' ? req.url : (protocol + '://' + host + req.url);
@@ -331,7 +334,7 @@ export default class UserReqHandler {
 
       .then(() => {
         // record request info
-        if (this.recorder) {
+        if (self.recorder) {
           resourceInfo = {
             host,
             method: req.method,
@@ -341,18 +344,18 @@ export default class UserReqHandler {
             req,
             startTime: new Date().getTime()
           };
-          resourceInfoId = this.recorder.appendRecord(resourceInfo);
+          resourceInfoId = self.recorder.appendRecord(resourceInfo);
         }
 
         try {
           resourceInfo.reqBody = reqData.toString(); //TODO: deal reqBody in webInterface.js
-          this.recorder && this.recorder.updateRecord(resourceInfoId, resourceInfo);
+          self.recorder && self.recorder.updateRecord(resourceInfoId, resourceInfo);
         } catch (e) { }
       })
 
       // invoke rule before sending request
       .then(co.wrap(function *() {
-        const userModifiedInfo = (yield this.userRule.beforeSendRequest(Object.assign({}, requestDetail))) || {};
+        const userModifiedInfo = (yield self.userRule.beforeSendRequest(Object.assign({}, requestDetail))) || {};
         const finalReqDetail = {};
         ['protocol', 'requestOptions', 'requestData', 'response'].map((key) => {
           finalReqDetail[key] = userModifiedInfo[key] || requestDetail[key]
@@ -368,7 +371,7 @@ export default class UserReqHandler {
           return userConfig;
         } else if (userConfig.requestOptions) {
           const remoteResponse = yield fetchRemoteResponse(userConfig.protocol, userConfig.requestOptions, userConfig.requestData, {
-            dangerouslyIgnoreUnauthorized: this.reqHandlerCtx.dangerouslyIgnoreUnauthorized,
+            dangerouslyIgnoreUnauthorized: self.reqHandlerCtx.dangerouslyIgnoreUnauthorized,
             chunkSizeThreshold,
           });
           return {
@@ -393,7 +396,7 @@ export default class UserReqHandler {
           return responseData;
         } else {
           // TODO: err etimeout
-          return (yield this.userRule.beforeSendResponse(Object.assign({}, requestDetail), Object.assign({}, responseData))) || responseData;
+          return (yield self.userRule.beforeSendResponse(Object.assign({}, requestDetail), Object.assign({}, responseData))) || responseData;
         }
       }))
 
@@ -404,7 +407,7 @@ export default class UserReqHandler {
 
         // call user rule
         try {
-          const userResponse = yield this.userRule.onError(Object.assign({}, requestDetail), error);
+          const userResponse = yield self.userRule.onError(Object.assign({}, requestDetail), error);
           if (userResponse && userResponse.response && userResponse.response.header) {
             errorResponse = userResponse.response;
           }
@@ -431,7 +434,7 @@ export default class UserReqHandler {
 
         // console.info('===> resbody in record', resourceInfo);
 
-        this.recorder && this.recorder.updateRecord(resourceInfoId, resourceInfo);
+        self.recorder && self.recorder.updateRecord(resourceInfoId, resourceInfo);
       })
       .catch((e) => {
         logUtil.printLog(color.green('Send final response failed:' + e.message), logUtil.T_ERR);
diff --git a/lib/requestHandler/index.js b/lib/requestHandler/index.js
index e2a249c..76b375c 100644
--- a/lib/requestHandler/index.js
+++ b/lib/requestHandler/index.js
@@ -1,5 +1,7 @@
 'use strict';
 
+import UserReqHandler from './UserReqHandler';
+
 const
   net = require('net'),
   color = require('colorful'),
@@ -10,8 +12,6 @@ const
   CommonReadableStream = require('./CommonReadableStream'),
   HttpsServerMgr = require('../httpsServerMgr');
 
-const UserReqHandler = require('./UserReqHandler').default;
-
 /**
 * get request info from the ws client, includes:
  host
@@ -429,7 +429,7 @@ class RequestHandler {
     const userRule = util.merge(default_rule, rule);
 
     const userReqHandler = new UserReqHandler(reqHandlerCtx, userRule, recorder);
-    reqHandlerCtx.userRequestHandler = userReqHandler.handler.bind(reqHandlerCtx);
+    reqHandlerCtx.userRequestHandler = userReqHandler.handler.bind(userReqHandler);
     reqHandlerCtx.wsHandler = getWsHandler.bind(this, userRule, recorder);
 
     reqHandlerCtx.httpsServerMgr = new HttpsServerMgr({
diff --git a/lib/util.ts b/lib/util.ts
index 6a6d227..ce34729 100644
--- a/lib/util.ts
+++ b/lib/util.ts
@@ -14,7 +14,7 @@ import * as mime from 'mime-types';
 import * as color from 'colorful';
 import { Buffer } from 'buffer';
 import { execSync } from 'child_process';
-import * as logUtil from './log';
+import logUtil from './log';
 
 
   const networkInterfaces = require('os').networkInterfaces();
diff --git a/types/index.d.ts b/types/index.d.ts
deleted file mode 100644
index e2535c1..0000000
--- a/types/index.d.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-export interface AnyProxyConfig {
-  port: number
-}
diff --git a/typings/index.d.ts b/typings/index.d.ts
new file mode 100644
index 0000000..fe83544
--- /dev/null
+++ b/typings/index.d.ts
@@ -0,0 +1,11 @@
+declare interface AnyProxyConfig {
+  port: number
+}
+declare interface AnyProxyRule {
+  summary?: string,
+  beforeSendRequest?: Function,
+  beforeSendResponse?: Function,
+  beforeDealHttpsRequest?: Function,
+  onError?: Function,
+  onConnectError?: Function
+}
\ No newline at end of file