diff --git a/lib/inc/drogon/HttpClient.h b/lib/inc/drogon/HttpClient.h
index 687efed7..26a4e7e3 100644
--- a/lib/inc/drogon/HttpClient.h
+++ b/lib/inc/drogon/HttpClient.h
@@ -1,14 +1,14 @@
 /**
  *
- *  @file
- *  @author An Tao
- *  @section LICENSE
+ *  HttpClient.h
+ * 
+ *  An Tao
  *
  *  Copyright 2018, An Tao.  All rights reserved.
  *  Use of this source code is governed by a MIT license
  *  that can be found in the License file.
  *
- *  @section DESCRIPTION
+ *  Drogon
  *
  */
 #pragma once
@@ -22,25 +22,55 @@ namespace drogon
 {
 enum class ReqResult
 {
-    Ok,
-    BadResponse,
-    NetworkFailure,
-    BadServerAddress,
-    Timeout
+  Ok,
+  BadResponse,
+  NetworkFailure,
+  BadServerAddress,
+  Timeout
 };
 typedef std::function<void(ReqResult, const HttpResponsePtr &response)> HttpReqCallback;
 class HttpClient;
 typedef std::shared_ptr<HttpClient> HttpClientPtr;
+
+///Async http client class
+/**
+ * HttpClient implementation object uses the HttpAppFramework's event loop,
+ * so you should call app().run() to make the client work.
+ * Each HttpClient object establishes a persistent connection with the server. 
+ * If the connection is broken, the client will attempt to reconnect 
+ * when calling the sendRequest method.
+ */
 class HttpClient : public trantor::NonCopyable
 {
-  public:
-    virtual void sendRequest(const HttpRequestPtr &req, const HttpReqCallback &callback) = 0;
-    virtual ~HttpClient() {}
-    static HttpClientPtr newHttpClient(const std::string &ip, uint16_t port, bool useSSL = false);
-    //        static HttpClientPtr newHttpClient(const trantor::InetAddress &addr,bool useSSL=false) ;
-    static HttpClientPtr newHttpClient(const std::string &hostString);
+public:
+  /// Send request to server
+  /**
+   * The response from http server will be got in
+   * the callback function
+   */
+  virtual void sendRequest(const HttpRequestPtr &req, const HttpReqCallback &callback) = 0;
 
-  protected:
-    HttpClient() = default;
+  virtual ~HttpClient() {}
+
+  /// Use ip and port to connect to server
+  /** If useSSL is set to true, the client will 
+   * connect to the server using https
+   */
+  static HttpClientPtr newHttpClient(const std::string &ip, uint16_t port, bool useSSL = false);
+
+  /// Use hostString to connect to server
+  /** Examples for hostString:
+   *  https://www.baidu.com
+   *  http://www.baidu.com
+   *  https://127.0.0.1:8080/
+   *  http://127.0.0.1
+   *  Note:don't add path and parameters in hostString, the request path 
+   *  and parameters should be set in 
+   *  HttpRequestPtr 
+   */
+  static HttpClientPtr newHttpClient(const std::string &hostString);
+
+protected:
+  HttpClient() = default;
 };
 } // namespace drogon
\ No newline at end of file
diff --git a/lib/src/HttpClientContext.cc b/lib/src/HttpClientContext.cc
index eed81cf6..dd02619f 100755
--- a/lib/src/HttpClientContext.cc
+++ b/lib/src/HttpClientContext.cc
@@ -113,10 +113,8 @@ bool HttpClientContext::parseResponse(MsgBuffer *buf)
                 }
                 else
                 {
-                    // empty line, end of header
-                    // FIXME:
                     std::string len = _response->getHeader("Content-Length");
-                    LOG_INFO << "content len=" << len;
+                    //LOG_INFO << "content len=" << len;
                     if (len != "")
                     {
                         _response->_left_body_length = atoi(len.c_str());