diff --git a/example/rest/book_server/book_services.cc b/example/rest/book_server/book_services.cc
index a3c4f69..39e916a 100644
--- a/example/rest/book_server/book_services.cc
+++ b/example/rest/book_server/book_services.cc
@@ -3,7 +3,6 @@
 #include <list>
 #include <iostream>
 
-#include "boost/lexical_cast.hpp"
 #include "boost/thread/thread.hpp"
 #include "json/json.h"
 #include "webcc/logger.h"
diff --git a/example/rest/book_server/main.cc b/example/rest/book_server/main.cc
index 6f1f5b0..02c03a0 100644
--- a/example/rest/book_server/main.cc
+++ b/example/rest/book_server/main.cc
@@ -36,7 +36,7 @@ int main(int argc, char* argv[]) {
 
   WEBCC_LOG_INIT("", webcc::LOG_CONSOLE);
 
-  unsigned short port = std::atoi(argv[1]);
+  std::uint16_t port = static_cast<std::uint16_t>(std::atoi(argv[1]));
 
   int sleep_seconds = 0;
   if (argc >= 3) {
@@ -56,7 +56,7 @@ int main(int argc, char* argv[]) {
 
     server.Run();
 
-  } catch (std::exception& e) {
+  } catch (const std::exception& e) {
     std::cerr << "Exception: " << e.what() << std::endl;
     return 1;
   }
diff --git a/example/soap/calc_client/calc_client.cc b/example/soap/calc_client/calc_client.cc
index 39f5ea8..e6e59ca 100644
--- a/example/soap/calc_client/calc_client.cc
+++ b/example/soap/calc_client/calc_client.cc
@@ -1,6 +1,7 @@
 #include "calc_client.h"
+
 #include <iostream>
-#include "boost/lexical_cast.hpp"
+
 #include "webcc/logger.h"
 
 // Set to 0 to test our own calculator server created with webcc.
@@ -80,8 +81,8 @@ bool CalcClient::Calc(const std::string& operation,
 
   // Convert the result from string to double.
   try {
-    *result = boost::lexical_cast<double>(result_str);
-  } catch (boost::bad_lexical_cast&) {
+    *result = std::stod(result_str);
+  } catch (const std::exception&) {
     return false;
   }
 
diff --git a/example/soap/calc_server/calc_service.cc b/example/soap/calc_server/calc_service.cc
index 4561260..0148241 100644
--- a/example/soap/calc_server/calc_service.cc
+++ b/example/soap/calc_server/calc_service.cc
@@ -1,10 +1,11 @@
 #include "calc_service.h"
 
+#include <functional>
+#include <string>
+
 // Sleep several seconds for the client to test timeout control.
 #define SLEEP_FOR_TIMEOUT_TEST 0
 
-#include "boost/lexical_cast.hpp"
-
 #if SLEEP_FOR_TIMEOUT_TEST
 #include "boost/thread/thread.hpp"
 #endif
@@ -82,10 +83,10 @@ bool CalcService::GetParameters(const webcc::SoapRequest& soap_request,
                                 double* x,
                                 double* y) {
   try {
-    *x = boost::lexical_cast<double>(soap_request.GetParameter("x"));
-    *y = boost::lexical_cast<double>(soap_request.GetParameter("y"));
+    *x = std::stod(soap_request.GetParameter("x"));
+    *y = std::stod(soap_request.GetParameter("y"));
 
-  } catch (boost::bad_lexical_cast& e) {
+  } catch (const std::exception& e) {
     LOG_ERRO("Parameter cast error: %s", e.what());
     return false;
   }
diff --git a/example/soap/calc_server/main.cc b/example/soap/calc_server/main.cc
index 3834ba4..a1584d8 100644
--- a/example/soap/calc_server/main.cc
+++ b/example/soap/calc_server/main.cc
@@ -19,7 +19,7 @@ int main(int argc, char* argv[]) {
 
   WEBCC_LOG_INIT("", webcc::LOG_CONSOLE);
 
-  unsigned short port = std::atoi(argv[1]);
+  std::uint16_t port = static_cast<std::uint16_t>(std::atoi(argv[1]));
 
   std::size_t workers = 2;
 
@@ -30,7 +30,7 @@ int main(int argc, char* argv[]) {
 
     server.Run();
 
-  } catch (std::exception& e) {
+  } catch (const std::exception& e) {
     std::cerr << "Exception: " << e.what() << std::endl;
     return 1;
   }
diff --git a/src/webcc/CMakeLists.txt b/src/webcc/CMakeLists.txt
index 6969bd0..c8248ef 100644
--- a/src/webcc/CMakeLists.txt
+++ b/src/webcc/CMakeLists.txt
@@ -1,6 +1,10 @@
 # Don't use any deprecated definitions (e.g., io_service).
 add_definitions(-DBOOST_ASIO_NO_DEPRECATED)
 
+if(MSVC)
+    add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+endif()
+
 set(SRCS
 	async_http_client.cc
 	async_http_client.h
diff --git a/src/webcc/async_http_client.cc b/src/webcc/async_http_client.cc
index 508dfee..f00b31f 100644
--- a/src/webcc/async_http_client.cc
+++ b/src/webcc/async_http_client.cc
@@ -18,12 +18,12 @@ extern void AdjustBufferSize(std::size_t content_length,
 
 AsyncHttpClient::AsyncHttpClient(boost::asio::io_context& io_context)
     : socket_(io_context),
+      resolver_(new tcp::resolver(io_context)),
       buffer_(kBufferSize),
+      deadline_(io_context),
       timeout_seconds_(kMaxReceiveSeconds),
-      deadline_(io_context) {
-  resolver_.reset(new tcp::resolver(io_context));
-  response_.reset(new HttpResponse());
-  response_parser_.reset(new HttpResponseParser(response_.get()));
+      stopped_(false),
+      timed_out_(false) {
 }
 
 Error AsyncHttpClient::Request(std::shared_ptr<HttpRequest> request,
@@ -31,6 +31,9 @@ Error AsyncHttpClient::Request(std::shared_ptr<HttpRequest> request,
   assert(request);
   assert(response_handler);
 
+  response_.reset(new HttpResponse());
+  response_parser_.reset(new HttpResponseParser(response_.get()));
+
   LOG_VERB("HTTP request:\n%s", request->Dump(4, "> ").c_str());
 
   request_ = request;
@@ -53,8 +56,10 @@ Error AsyncHttpClient::Request(std::shared_ptr<HttpRequest> request,
 
 void AsyncHttpClient::Stop() {
   stopped_ = true;
+
   boost::system::error_code ignored_ec;
   socket_.close(ignored_ec);
+
   deadline_.cancel();
 }
 
@@ -72,7 +77,8 @@ void AsyncHttpClient::ResolveHandler(boost::system::error_code ec,
     // Start the deadline actor. You will note that we're not setting any
     // particular deadline here. Instead, the connect and input actors will
     // update the deadline prior to each asynchronous operation.
-    deadline_.async_wait(std::bind(&AsyncHttpClient::CheckDeadline, this));
+    deadline_.async_wait(std::bind(&AsyncHttpClient::CheckDeadline,
+                                   shared_from_this()));
   }
 }
 
@@ -110,7 +116,6 @@ void AsyncHttpClient::ConnectHandler(boost::system::error_code ec,
     // of the asynchronous operation. If the socket is closed at this time then
     // the timeout handler must have run first.
     LOG_WARN("Connect timed out.");
-
     // Try the next available endpoint.
     AsyncConnect(++endpoint_iter);
   } else if (ec) {    
@@ -118,7 +123,6 @@ void AsyncHttpClient::ConnectHandler(boost::system::error_code ec,
     // We need to close the socket used in the previous connection attempt
     // before starting a new one.
     socket_.close();
-
     // Try the next available endpoint.
     AsyncConnect(++endpoint_iter);
   } else {
diff --git a/src/webcc/async_http_client.h b/src/webcc/async_http_client.h
index c3c1d95..311bc01 100644
--- a/src/webcc/async_http_client.h
+++ b/src/webcc/async_http_client.h
@@ -16,6 +16,7 @@
 
 namespace webcc {
 
+// Request handler/callback.
 typedef std::function<void(HttpResponsePtr, Error, bool)> HttpResponseHandler;
 
 class AsyncHttpClient : public std::enable_shared_from_this<AsyncHttpClient> {
@@ -57,29 +58,26 @@ class AsyncHttpClient : public std::enable_shared_from_this<AsyncHttpClient> {
 
   void CheckDeadline();
 
-  bool stopped_ = false;
-  bool timed_out_ = false;
-
   tcp::socket socket_;
-
-  std::shared_ptr<HttpRequest> request_;
-
   std::unique_ptr<tcp::resolver> resolver_;
   tcp::resolver::results_type endpoints_;
 
+  std::shared_ptr<HttpRequest> request_;
   std::vector<char> buffer_;
 
-  std::unique_ptr<HttpResponseParser> response_parser_;
-
   HttpResponsePtr response_;
+  std::unique_ptr<HttpResponseParser> response_parser_;
   HttpResponseHandler response_handler_;
 
+  // Timer for the timeout control.
+  boost::asio::deadline_timer deadline_;
+
   // Maximum seconds to wait before the client cancels the operation.
   // Only for receiving response from server.
   int timeout_seconds_;
 
-  // Timer for the timeout control.
-  boost::asio::deadline_timer deadline_;
+  bool stopped_;
+  bool timed_out_;
 };
 
 typedef std::shared_ptr<AsyncHttpClient> HttpAsyncClientPtr;
diff --git a/src/webcc/async_rest_client.cc b/src/webcc/async_rest_client.cc
index d2c26ce..98d8319 100644
--- a/src/webcc/async_rest_client.cc
+++ b/src/webcc/async_rest_client.cc
@@ -2,6 +2,12 @@
 
 namespace webcc {
 
+AsyncRestClient::AsyncRestClient(boost::asio::io_context& io_context,
+                                 const std::string& host,
+                                 const std::string& port)
+    : io_context_(io_context), host_(host), port_(port), timeout_seconds_(0) {
+}
+
 void AsyncRestClient::Request(const std::string& method,
                               const std::string& url,
                               const std::string& content,
@@ -21,6 +27,11 @@ void AsyncRestClient::Request(const std::string& method,
   request->Build();
 
   HttpAsyncClientPtr http_client(new AsyncHttpClient(io_context_));
+
+  if (timeout_seconds_ > 0) {
+    http_client->set_timeout_seconds(timeout_seconds_);
+  }
+
   http_client->Request(request, response_handler_);
 }
 
diff --git a/src/webcc/async_rest_client.h b/src/webcc/async_rest_client.h
index bde667c..0ef332b 100644
--- a/src/webcc/async_rest_client.h
+++ b/src/webcc/async_rest_client.h
@@ -3,16 +3,18 @@
 
 #include <string>
 
-#include "webcc/globals.h"
 #include "webcc/async_http_client.h"
 
 namespace webcc {
 
 class AsyncRestClient {
  public:
-  AsyncRestClient(boost::asio::io_context& io_context,
-                  const std::string& host, const std::string& port)
-      : io_context_(io_context), host_(host), port_(port) {
+  AsyncRestClient(boost::asio::io_context& io_context,  // NOLINT
+                  const std::string& host,
+                  const std::string& port);
+
+  void set_timeout_seconds(int timeout_seconds) {
+    timeout_seconds_ = timeout_seconds;
   }
 
   void Get(const std::string& url,
@@ -50,9 +52,14 @@ class AsyncRestClient {
                HttpResponseHandler response_handler);
 
   boost::asio::io_context& io_context_;
+
   std::string host_;
   std::string port_;
+
   HttpResponseHandler response_handler_;
+
+  // Timeout in seconds; only effective when > 0.
+  int timeout_seconds_;
 };
 
 }  // namespace webcc
diff --git a/src/webcc/globals.cc b/src/webcc/globals.cc
index 85aced5..0bd937e 100644
--- a/src/webcc/globals.cc
+++ b/src/webcc/globals.cc
@@ -6,27 +6,31 @@ namespace webcc {
 
 // -----------------------------------------------------------------------------
 
-// NOTE:
-// Field names are case-insensitive.
-// See: https://stackoverflow.com/a/5259004
+// NOTE: Field names are case-insensitive.
+//   See https://stackoverflow.com/a/5259004 for more details.
+const std::string kHost = "Host";
 const std::string kContentType = "Content-Type";
 const std::string kContentLength = "Content-Length";
+
+#ifdef WEBCC_ENABLE_SOAP
 const std::string kSoapAction = "SOAPAction";
-const std::string kHost = "Host";
+#endif  // WEBCC_ENABLE_SOAP
+
+const std::string kTextJsonUtf8 = "text/json; charset=utf-8";
 
+#ifdef WEBCC_ENABLE_SOAP
 // According to www.w3.org when placing SOAP messages in HTTP bodies, the HTTP
 // Content-type header must be chosen as "application/soap+xml" [RFC 3902].
 // But in practice, many web servers cannot understand it.
 // See: https://www.w3.org/TR/2007/REC-soap12-part0-20070427/#L26854
 const std::string kTextXmlUtf8 = "text/xml; charset=utf-8";
+#endif  // WEBCC_ENABLE_SOAP
 
-const std::string kTextJsonUtf8 = "text/json; charset=utf-8";
-
-const std::string kHttpHead = "HEAD";
-const std::string kHttpGet = "GET";
-const std::string kHttpPost = "POST";
-const std::string kHttpPatch = "PATCH";
-const std::string kHttpPut = "PUT";
+const std::string kHttpHead   = "HEAD";
+const std::string kHttpGet    = "GET";
+const std::string kHttpPost   = "POST";
+const std::string kHttpPatch  = "PATCH";
+const std::string kHttpPut    = "PUT";
 const std::string kHttpDelete = "DELETE";
 
 // -----------------------------------------------------------------------------
@@ -65,35 +69,27 @@ Parameter::Parameter(const std::string& key, std::string&& value)
 }
 
 Parameter::Parameter(const std::string& key, int value)
-    : key_(key) {
-  value_ = std::to_string(value);
+    : key_(key), value_(std::to_string(value)) {
 }
 
 Parameter::Parameter(const std::string& key, double value)
-    : key_(key) {
-  value_ = std::to_string(value);
+    : key_(key), value_(std::to_string(value)) {
 }
 
 Parameter::Parameter(const std::string& key, bool value)
-    : key_(key) {
-  value_ = value ? "true" : "false";
+    : key_(key), value_(value ? "true" : "false") {
 }
 
 Parameter::Parameter(Parameter&& rhs)
-    : key_(std::move(rhs.key_)),
-      value_(std::move(rhs.value_)) {
+    : key_(std::move(rhs.key_)), value_(std::move(rhs.value_)) {
 }
 
 Parameter& Parameter::operator=(Parameter&& rhs) {
-  if (this != &rhs) {
+  if (&rhs != this) {
     key_ = std::move(rhs.key_);
     value_ = std::move(rhs.value_);
   }
   return *this;
 }
 
-std::string Parameter::ToString() const {
-  return key_ + "=" + value_;
-}
-
 }  // namespace webcc
diff --git a/src/webcc/globals.h b/src/webcc/globals.h
index 4208c12..8098a0a 100644
--- a/src/webcc/globals.h
+++ b/src/webcc/globals.h
@@ -23,18 +23,25 @@ const std::size_t kBufferSize = 1024;
 const std::size_t kInvalidLength = static_cast<std::size_t>(-1);
 
 // Timeout seconds.
+// TODO
 const int kMaxConnectSeconds = 10;
-const int kMaxSendSeconds = 10;
+const int kMaxSendSeconds = 30;
 const int kMaxReceiveSeconds = 30;
 
+extern const std::string kHost;
 extern const std::string kContentType;
 extern const std::string kContentLength;
+
+#ifdef WEBCC_ENABLE_SOAP
 extern const std::string kSoapAction;
-extern const std::string kHost;
+#endif  // WEBCC_ENABLE_SOAP
 
-extern const std::string kTextXmlUtf8;
 extern const std::string kTextJsonUtf8;
 
+#ifdef WEBCC_ENABLE_SOAP
+extern const std::string kTextXmlUtf8;
+#endif  // WEBCC_ENABLE_SOAP
+
 // HTTP methods (verbs) in string ("HEAD", "GET", etc.).
 // NOTE: Don't use enum to avoid converting back and forth.
 extern const std::string kHttpHead;
@@ -99,25 +106,16 @@ class Parameter {
   // Use "= default" if drop the support of VS 2013.
   Parameter& operator=(Parameter&& rhs);
 
-  const std::string& key() const {
-    return key_;
-  }
+  const std::string& key() const { return key_; }
+  const std::string& value() const { return value_; }
 
-  const std::string& value() const {
-    return value_;
-  }
+  const char* c_key() const { return key_.c_str(); }
+  const char* c_value() const { return value_.c_str(); }
 
-  const char* c_key() const {
-    return key_.c_str();
+  std::string ToString() const {
+    return key_ + "=" + value_;
   }
 
-  const char* c_value() const {
-    return value_.c_str();
-  }
-
-  // Return "key=value" string.
-  std::string ToString() const;
-
  private:
   std::string key_;
   std::string value_;
diff --git a/src/webcc/http_client.cc b/src/webcc/http_client.cc
index 40694b6..9020afc 100644
--- a/src/webcc/http_client.cc
+++ b/src/webcc/http_client.cc
@@ -10,8 +10,6 @@
 #include "boost/lambda/lambda.hpp"
 
 #include "webcc/logger.h"
-#include "webcc/http_request.h"
-#include "webcc/http_response.h"
 
 // NOTE:
 // The timeout control is inspired by the following Asio example:
@@ -34,17 +32,20 @@ void AdjustBufferSize(std::size_t content_length, std::vector<char>* buffer) {
   std::size_t min_buffer_size = content_length / kMaxTimes;
   if (min_buffer_size > buffer->size()) {
     buffer->resize(std::min(min_buffer_size, kMaxBufferSize));
-    LOG_INFO("Resize read buffer to %d.", buffer->size());
+    LOG_INFO("Resize read buffer to %u.", buffer->size());
   } else {
-    LOG_INFO("Keep the current buffer size (%d).", buffer->size());
+    LOG_INFO("Keep the current buffer size: %u.", buffer->size());
   }
 }
 
 HttpClient::HttpClient()
     : socket_(io_context_),
       buffer_(kBufferSize),
+      deadline_(io_context_),
       timeout_seconds_(kMaxReceiveSeconds),
-      deadline_(io_context_) {
+      stopped_(false),
+      timed_out_(false),
+      error_(kNoError) {
 }
 
 bool HttpClient::Request(const HttpRequest& request) {
@@ -189,7 +190,7 @@ void HttpClient::DoReadResponse(Error* error) {
           return;
         }
 
-        LOG_INFO("Read data, length: %d.", length);
+        LOG_INFO("Read data, length: %u.", length);
 
         bool content_length_parsed = response_parser_->content_length_parsed();
 
diff --git a/src/webcc/http_client.h b/src/webcc/http_client.h
index cd940db..838d24e 100644
--- a/src/webcc/http_client.h
+++ b/src/webcc/http_client.h
@@ -19,7 +19,6 @@ namespace webcc {
 class HttpClient {
  public:
   HttpClient();
-
   ~HttpClient() = default;
 
   DELETE_COPY_AND_ASSIGN(HttpClient);
@@ -31,10 +30,10 @@ class HttpClient {
 
   HttpResponsePtr response() const { return response_; }
 
-  Error error() const { return error_; }
-
   bool timed_out() const { return timed_out_; }
 
+  Error error() const { return error_; }
+
   // Connect to server, send request, wait until response is received.
   bool Request(const HttpRequest& request);
 
@@ -53,7 +52,6 @@ class HttpClient {
   void CheckDeadline();
 
   boost::asio::io_context io_context_;
-
   boost::asio::ip::tcp::socket socket_;
 
   std::vector<char> buffer_;
@@ -61,18 +59,18 @@ class HttpClient {
   HttpResponsePtr response_;
   std::unique_ptr<HttpResponseParser> response_parser_;
 
-  Error error_ = kNoError;
-
-  bool stopped_ = false;
-
-  // If the error was caused by timeout or not.
-  bool timed_out_ = false;
+  boost::asio::deadline_timer deadline_;
 
   // Maximum seconds to wait before the client cancels the operation.
   // Only for receiving response from server.
   int timeout_seconds_;
 
-  boost::asio::deadline_timer deadline_;
+  bool stopped_;
+
+  // If the error was caused by timeout or not.
+  bool timed_out_;
+
+  Error error_;
 };
 
 }  // namespace webcc
diff --git a/src/webcc/http_connection.cc b/src/webcc/http_connection.cc
index 95f0a23..f8f6120 100644
--- a/src/webcc/http_connection.cc
+++ b/src/webcc/http_connection.cc
@@ -91,7 +91,7 @@ void HttpConnection::AsyncWrite() {
 void HttpConnection::WriteHandler(boost::system::error_code ec,
                                   std::size_t length) {
   if (!ec) {
-    LOG_INFO("Response has been sent back.");
+    LOG_INFO("Response has been sent back, length: %u.", length);
 
     // Initiate graceful connection closure.
     boost::system::error_code ec;
diff --git a/src/webcc/http_connection.h b/src/webcc/http_connection.h
index 56981d1..644cbcd 100644
--- a/src/webcc/http_connection.h
+++ b/src/webcc/http_connection.h
@@ -18,7 +18,7 @@ class HttpRequestHandler;
 
 class HttpConnection : public std::enable_shared_from_this<HttpConnection> {
  public:
-  HttpConnection(boost::asio::ip::tcp::socket socket,
+  HttpConnection(boost::asio::ip::tcp::socket socket,  // Will be moved
                  HttpRequestHandler* handler);
 
   ~HttpConnection() = default;
diff --git a/src/webcc/http_message.h b/src/webcc/http_message.h
index 21a3778..d2f78a1 100644
--- a/src/webcc/http_message.h
+++ b/src/webcc/http_message.h
@@ -10,8 +10,7 @@
 
 namespace webcc {
 
-class HttpHeader {
- public:
+struct HttpHeader {
   std::string name;
   std::string value;
 };
@@ -21,20 +20,15 @@ class HttpMessage {
  public:
   virtual ~HttpMessage() = default;
 
-  const std::string& start_line() const {
-    return start_line_;
-  }
+  const std::string& start_line() const { return start_line_; }
+
   void set_start_line(const std::string& start_line) {
     start_line_ = start_line;
   }
 
-  std::size_t content_length() const {
-    return content_length_;
-  }
+  std::size_t content_length() const { return content_length_; }
 
-  const std::string& content() const {
-    return content_;
-  }
+  const std::string& content() const { return content_; }
 
   void SetHeader(const std::string& name, const std::string& value);
 
diff --git a/src/webcc/http_parser.cc b/src/webcc/http_parser.cc
index 65c91e1..990d64a 100644
--- a/src/webcc/http_parser.cc
+++ b/src/webcc/http_parser.cc
@@ -1,7 +1,6 @@
 #include "webcc/http_parser.h"
 
 #include "boost/algorithm/string.hpp"
-#include "boost/lexical_cast.hpp"
 
 #include "webcc/http_message.h"
 #include "webcc/logger.h"
@@ -111,23 +110,24 @@ void HttpParser::ParseContentLength(const std::string& line) {
     std::string value = line.substr(pos);
 
     try {
-      content_length_ = boost::lexical_cast<std::size_t>(value);
-      LOG_INFO("Content length: %d", content_length_);
+      content_length_ = static_cast<std::size_t>(std::stoul(value));
+    } catch (const std::exception& e) {
+      LOG_ERRO("Invalid content length: %s.", value.c_str());
+    }
+
+    LOG_INFO("Content length: %u.", content_length_);
 
+    try {
       // Reserve memory to avoid frequent reallocation when append.
-      try {
-        content_.reserve(content_length_);
-      } catch (std::exception& e) {
-        LOG_ERRO("Failed to reserve content memory: %s.", e.what());
-      }
-    } catch (boost::bad_lexical_cast&) {
-      LOG_ERRO("Invalid content length: %s.", value.c_str());
+      content_.reserve(content_length_);
+    } catch (const std::exception& e) {
+      LOG_ERRO("Failed to reserve content memory: %s.", e.what());
     }
   }
 }
 
 void HttpParser::Finish() {
-  // Move temp content to message.
+  // Move content to message.
   message_->SetContent(std::move(content_));
   finished_ = true;
 }
diff --git a/src/webcc/http_parser.h b/src/webcc/http_parser.h
index 7fe8830..96fe392 100644
--- a/src/webcc/http_parser.h
+++ b/src/webcc/http_parser.h
@@ -40,8 +40,6 @@ class HttpParser {
   // The result HTTP message.
   HttpMessage* message_;
 
-  Error error_;
-
   // Data waiting to be parsed.
   std::string pending_data_;
 
diff --git a/src/webcc/http_request.cc b/src/webcc/http_request.cc
index a2e0e32..b235245 100644
--- a/src/webcc/http_request.cc
+++ b/src/webcc/http_request.cc
@@ -2,6 +2,17 @@
 
 namespace webcc {
 
+// -----------------------------------------------------------------------------
+
+namespace misc_strings {
+
+const char NAME_VALUE_SEPARATOR[] = { ':', ' ' };
+const char CRLF[] = { '\r', '\n' };
+
+}  // misc_strings
+
+// -----------------------------------------------------------------------------
+
 void HttpRequest::SetHost(const std::string& host, const std::string& port) {
   host_ = host;
   port_ = port;
@@ -22,13 +33,6 @@ void HttpRequest::Build() {
   }
 }
 
-namespace misc_strings {
-
-const char NAME_VALUE_SEPARATOR[] = { ':', ' ' };
-const char CRLF[] = { '\r', '\n' };
-
-}  // misc_strings
-
 // ATTENTION: The buffers don't hold the memory!
 std::vector<boost::asio::const_buffer> HttpRequest::ToBuffers() const {
   assert(!start_line_.empty());
diff --git a/src/webcc/http_request.h b/src/webcc/http_request.h
index f2bd237..1ed49ed 100644
--- a/src/webcc/http_request.h
+++ b/src/webcc/http_request.h
@@ -19,29 +19,14 @@ class HttpRequest : public HttpMessage {
 
   virtual ~HttpRequest() = default;
 
-  const std::string& method() const {
-    return method_;
-  }
+  const std::string& method() const { return method_; }
+  void set_method(const std::string& method) { method_ = method; }
 
-  void set_method(const std::string& method) {
-    method_ = method;
-  }
+  const std::string& url() const { return url_; }
+  void set_url(const std::string& url) { url_ = url; }
 
-  const std::string& url() const {
-    return url_;
-  }
-
-  void set_url(const std::string& url) {
-    url_ = url;
-  }
-
-  const std::string& host() const {
-    return host_;
-  }
-
-  const std::string& port() const {
-    return port_;
-  }
+  const std::string& host() const { return host_; }
+  const std::string& port() const { return port_; }
 
   // Set host name and port number.
   // The |host| is a descriptive name or a numeric IP address. The |port| is
diff --git a/src/webcc/http_response.h b/src/webcc/http_response.h
index d6a66b5..8f94e44 100644
--- a/src/webcc/http_response.h
+++ b/src/webcc/http_response.h
@@ -13,16 +13,13 @@ namespace webcc {
 
 class HttpResponse : public HttpMessage {
  public:
-  HttpResponse() = default;
-  ~HttpResponse() override = default;
-
-  int status() const {
-    return status_;
+  HttpResponse() : status_(HttpStatus::kOK) {
   }
 
-  void set_status(int status) {
-    status_ = status;
-  }
+  ~HttpResponse() override = default;
+
+  int status() const { return status_; }
+  void set_status(int status) { status_ = status; }
 
   // Convert the response into a vector of buffers. The buffers do not own the
   // underlying memory blocks, therefore the response object must remain valid
@@ -33,7 +30,7 @@ class HttpResponse : public HttpMessage {
   static HttpResponse Fault(HttpStatus::Enum status);
 
  private:
-  int status_ = HttpStatus::kOK;
+  int status_;
 };
 
 typedef std::shared_ptr<HttpResponse> HttpResponsePtr;
diff --git a/src/webcc/http_response_parser.cc b/src/webcc/http_response_parser.cc
index f21993b..f79083a 100644
--- a/src/webcc/http_response_parser.cc
+++ b/src/webcc/http_response_parser.cc
@@ -1,7 +1,5 @@
 #include "webcc/http_response_parser.h"
 
-#include "boost/lexical_cast.hpp"
-
 #include "webcc/logger.h"
 #include "webcc/http_response.h"
 
@@ -34,8 +32,8 @@ bool HttpResponseParser::ParseStartLine(const std::string& line) {
   std::string status_str = line.substr(off, pos - off);
 
   try {
-    response_->set_status(boost::lexical_cast<int>(status_str));
-  } catch (boost::bad_lexical_cast&) {
+    response_->set_status(std::stoi(status_str));
+  } catch (const std::exception&) {
     LOG_ERRO("Invalid HTTP status: %s", status_str.c_str());
     return false;
   }
diff --git a/src/webcc/http_server.cc b/src/webcc/http_server.cc
index ec8cedc..146ea05 100644
--- a/src/webcc/http_server.cc
+++ b/src/webcc/http_server.cc
@@ -12,7 +12,7 @@ using tcp = boost::asio::ip::tcp;
 
 namespace webcc {
 
-HttpServer::HttpServer(unsigned short port, std::size_t workers)
+HttpServer::HttpServer(std::uint16_t port, std::size_t workers)
     : signals_(io_context_) , workers_(workers) {
   // Register to handle the signals that indicate when the server should exit.
   // It is safe to register for the same signal multiple times in a program,
diff --git a/src/webcc/http_server.h b/src/webcc/http_server.h
index 85afec0..17615a0 100644
--- a/src/webcc/http_server.h
+++ b/src/webcc/http_server.h
@@ -21,7 +21,7 @@ class HttpRequestHandler;
 // NOTE: Only support IPv4.
 class HttpServer {
  public:
-  HttpServer(unsigned short port, std::size_t workers);
+  HttpServer(std::uint16_t port, std::size_t workers);
 
   virtual ~HttpServer() = default;
 
diff --git a/src/webcc/logger.cc b/src/webcc/logger.cc
index a5889e2..6d31cac 100644
--- a/src/webcc/logger.cc
+++ b/src/webcc/logger.cc
@@ -56,7 +56,7 @@ namespace bfs = boost::filesystem;
 
 static bfs::path InitLogPath(const std::string& dir) {
   if (dir.empty()) {
-    return bfs::current_path() / WEBCC_LOG_FILE;
+    return bfs::current_path() / WEBCC_LOG_FILE_NAME;
   }
 
   bfs::path path = bfs::path(dir);
@@ -67,7 +67,7 @@ static bfs::path InitLogPath(const std::string& dir) {
     }
   }
 
-  path /= WEBCC_LOG_FILE;
+  path /= WEBCC_LOG_FILE_NAME;
   return path;
 }
 
diff --git a/src/webcc/logger.h b/src/webcc/logger.h
index 0b5a1ea..b8f37e9 100644
--- a/src/webcc/logger.h
+++ b/src/webcc/logger.h
@@ -8,18 +8,21 @@
 #include <cstring>  // for strrchr()
 #include <string>
 
-#define WEBCC_VERB 0
+// Log levels.
+#define WEBCC_VERB 0  // Similar to DEBUG in other projects.
 #define WEBCC_INFO 1
 #define WEBCC_WARN 2
 #define WEBCC_ERRO 3
 #define WEBCC_FATA 4
 
 // Default log level.
+// You have to define a proper log level in CMakeLists.txt, e.g.,
+//   add_definitions(-DWEBCC_LOG_LEVEL=2)
 #ifndef WEBCC_LOG_LEVEL
 #define WEBCC_LOG_LEVEL WEBCC_WARN
 #endif
 
-#define WEBCC_LOG_FILE "webcc.log"
+#define WEBCC_LOG_FILE_NAME "webcc.log"
 
 namespace webcc {
 
@@ -129,7 +132,7 @@ void LogWrite(int level, const char* file, int line, const char* format, ...);
 
 #else  // WEBCC_ENABLE_LOG == 0
 
-#define WEBCC_LOG_INIT(modes)
+#define WEBCC_LOG_INIT(dir, modes)
 
 #if (defined(WIN32) || defined(_WIN64))
 #define LOG_VERB(format, ...)
diff --git a/src/webcc/rest_client.cc b/src/webcc/rest_client.cc
index 0d4f878..466400f 100644
--- a/src/webcc/rest_client.cc
+++ b/src/webcc/rest_client.cc
@@ -5,10 +5,19 @@
 
 namespace webcc {
 
+RestClient::RestClient(const std::string& host, const std::string& port)
+    : host_(host),
+      port_(port),
+      timeout_seconds_(0),
+      timed_out_(false),
+      error_(kNoError) {
+}
+
 bool RestClient::Request(const std::string& method,
                          const std::string& url,
                          const std::string& content) {
   response_.reset();
+
   error_ = kNoError;
   timed_out_ = false;
 
diff --git a/src/webcc/rest_client.h b/src/webcc/rest_client.h
index 9615281..28a9ede 100644
--- a/src/webcc/rest_client.h
+++ b/src/webcc/rest_client.h
@@ -11,9 +11,11 @@ namespace webcc {
 
 class RestClient {
  public:
-  RestClient(const std::string& host, const std::string& port)
-      : host_(host), port_(port) {
-  }
+  RestClient(const std::string& host, const std::string& port);
+
+  ~RestClient() = default;
+
+  DELETE_COPY_AND_ASSIGN(RestClient);
 
   void set_timeout_seconds(int timeout_seconds) {
     timeout_seconds_ = timeout_seconds;
@@ -31,27 +33,27 @@ class RestClient {
     return response_->content();
   }
 
-  Error error() const { return error_; }
-
   bool timed_out() const { return timed_out_; }
 
-  bool Get(const std::string& url) {
+  Error error() const { return error_; }
+
+  inline bool Get(const std::string& url) {
     return Request(kHttpGet, url, "");
   }
 
-  bool Post(const std::string& url, const std::string& content) {
+  inline bool Post(const std::string& url, const std::string& content) {
     return Request(kHttpPost, url, content);
   }
 
-  bool Put(const std::string& url, const std::string& content) {
+  inline bool Put(const std::string& url, const std::string& content) {
     return Request(kHttpPut, url, content);
   }
 
-  bool Patch(const std::string& url, const std::string& content) {
+  inline bool Patch(const std::string& url, const std::string& content) {
     return Request(kHttpPatch, url, content);
   }
 
-  bool Delete(const std::string& url) {
+  inline bool Delete(const std::string& url) {
     return Request(kHttpDelete, url, "");
   }
 
@@ -64,14 +66,14 @@ class RestClient {
   std::string port_;
 
   // Timeout in seconds; only effective when > 0.
-  int timeout_seconds_ = 0;
+  int timeout_seconds_;
 
   HttpResponsePtr response_;
 
-  Error error_ = kNoError;
-
   // If the error was caused by timeout or not.
-  bool timed_out_ = false;
+  bool timed_out_;
+
+  Error error_;
 };
 
 }  // namespace webcc
diff --git a/src/webcc/rest_server.h b/src/webcc/rest_server.h
index 82d3560..d1c5bcf 100644
--- a/src/webcc/rest_server.h
+++ b/src/webcc/rest_server.h
@@ -13,7 +13,7 @@ namespace webcc {
 
 class RestServer : public HttpServer {
  public:
-  RestServer(unsigned short port, std::size_t workers)
+  RestServer(std::uint16_t port, std::size_t workers)
       : HttpServer(port, workers) {
   }
 
diff --git a/src/webcc/rest_service.h b/src/webcc/rest_service.h
index 2fb1ec0..375a449 100644
--- a/src/webcc/rest_service.h
+++ b/src/webcc/rest_service.h
@@ -53,8 +53,7 @@ class RestListService : public RestService {
  protected:
   RestListService() = default;
 
-  virtual bool Get(const UrlQuery& query,
-                   std::string* response_content) {
+  virtual bool Get(const UrlQuery& query, std::string* response_content) {
     return false;
   }
 
diff --git a/src/webcc/soap_client.h b/src/webcc/soap_client.h
index 522db54..b4d519b 100644
--- a/src/webcc/soap_client.h
+++ b/src/webcc/soap_client.h
@@ -18,7 +18,8 @@ class SoapClient {
   bool timed_out() const { return timed_out_; }
 
  protected:
-  SoapClient() = default;
+  SoapClient() : timeout_seconds_(0), timed_out_(false) {
+  }
 
   // A generic wrapper to make a call.
   // NOTE: The parameters should be movable.
@@ -27,10 +28,10 @@ class SoapClient {
              std::string* result);
 
   // Timeout in seconds; only effective when > 0.
-  int timeout_seconds_ = 0;
+  int timeout_seconds_;
 
   // If the error was caused by timeout or not.
-  bool timed_out_ = false;
+  bool timed_out_;
 
   SoapNamespace soapenv_ns_;  // SOAP envelope namespace.
   SoapNamespace service_ns_;  // Namespace for your web service.
diff --git a/src/webcc/soap_server.h b/src/webcc/soap_server.h
index 200e9ad..043371b 100644
--- a/src/webcc/soap_server.h
+++ b/src/webcc/soap_server.h
@@ -12,7 +12,7 @@ namespace webcc {
 
 class SoapServer : public HttpServer {
  public:
-  SoapServer(unsigned short port, std::size_t workers)
+  SoapServer(std::uint16_t port, std::size_t workers)
       : HttpServer(port, workers) {
   }