diff --git a/example/rest_book_client/main.cc b/example/rest_book_client/main.cc
index d6e6c15..04f95eb 100644
--- a/example/rest_book_client/main.cc
+++ b/example/rest_book_client/main.cc
@@ -1,78 +1,50 @@
 #include <iostream>
 
 #include "boost/algorithm/string.hpp"
-#include "json/json.h"  // jsoncpp
+#include "json/json.h"
 
 #include "webcc/logger.h"
 #include "webcc/http_client.h"
 #include "webcc/http_request.h"
 #include "webcc/http_response.h"
+#include "webcc/rest_client.h"
 
 ////////////////////////////////////////////////////////////////////////////////
 
-class BookClientBase {
-public:
-  BookClientBase(const std::string& host, const std::string& port)
-      : host_(host), port_(port) {
-  }
-
-  bool Request(const std::string& method,
-               const std::string& url,
-               const std::string& content,
-               webcc::HttpResponse* http_response) {
-    webcc::HttpRequest http_request;
-
-    http_request.set_method(method);
-    http_request.set_url(url);
-    http_request.SetHost(host_, port_);
-    if (!content.empty()) {  // TODO
-      http_request.SetContent(content);
-    }
-    http_request.Build();
-
-    webcc::HttpClient http_client;
-    webcc::Error error = http_client.MakeRequest(http_request, http_response);
-
-    return error == webcc::kNoError;
-  }
-
-protected:
-  std::string host_;
-  std::string port_;
-};
+// Write a JSON object to string.
+std::string JsonToString(const Json::Value& json) {
+  Json::StreamWriterBuilder builder;
+  return Json::writeString(builder, json);
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 
-class BookListClient : public BookClientBase {
+class BookListClient {
 public:
   BookListClient(const std::string& host, const std::string& port)
-      : BookClientBase(host, port) {
+      : rest_client_(host, port) {
   }
 
   bool ListBooks() {
     webcc::HttpResponse http_response;
-    if (!Request(webcc::kHttpGet, "/books", "", &http_response)) {
+    if (!rest_client_.Get("/books", &http_response)) {
       return false;
     }
 
     std::cout << "result:\n" << http_response.content() << std::endl;
-
     return true;
   }
 
   bool CreateBook(const std::string& id,
                   const std::string& title,
                   double price) {
-    Json::Value root(Json::objectValue);
-    root["id"] = id;
-    root["title"] = title;
-    root["price"] = price;
-
-    Json::StreamWriterBuilder builder;
-    std::string book_json = Json::writeString(builder, root);
+    Json::Value json(Json::objectValue);
+    json["id"] = id;
+    json["title"] = title;
+    json["price"] = price;
 
     webcc::HttpResponse http_response;
-    if (!Request(webcc::kHttpPost, "/books", book_json, &http_response)) {
+    if (!rest_client_.Post("/books", JsonToString(json), &http_response)) {
       return false;
     }
 
@@ -80,58 +52,58 @@ public:
 
     return true;
   }
+
+private:
+  webcc::RestClient rest_client_;
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 
-class BookDetailClient : public BookClientBase {
+class BookDetailClient {
 public:
   BookDetailClient(const std::string& host, const std::string& port)
-      : BookClientBase(host, port) {
+      : rest_client_(host, port) {
   }
 
   bool GetBook(const std::string& id) {
     webcc::HttpResponse http_response;
-    if (!Request(webcc::kHttpGet, "/book/" + id, "", &http_response)) {
+    if (!rest_client_.Get("/book/" + id, &http_response)) {
       return false;
     }
 
     std::cout << http_response.content() << std::endl;
-
     return true;
   }
 
   bool UpdateBook(const std::string& id,
                   const std::string& title,
                   double price) {
-    Json::Value root(Json::objectValue);
-    // root["id"] = id;  // NOTE: ID is already in the URL.
-    root["title"] = title;
-    root["price"] = price;
-
-    Json::StreamWriterBuilder builder;
-    std::string book_json = Json::writeString(builder, root);
+    // NOTE: ID is already in the URL.
+    Json::Value json(Json::objectValue);
+    json["title"] = title;
+    json["price"] = price;
 
     webcc::HttpResponse http_response;
-    if (!Request(webcc::kHttpPost, "/book/" + id, book_json, &http_response)) {
+    if (!rest_client_.Post("/book/" + id, JsonToString(json), &http_response)) {
       return false;
     }
 
     std::cout << http_response.status() << std::endl;
-
     return true;
   }
 
   bool DeleteBook(const std::string& id) {
     webcc::HttpResponse http_response;
-    if (!Request(webcc::kHttpDelete, "/book/" + id, "", &http_response)) {
+    if (!rest_client_.Delete("/book/" + id, &http_response)) {
       return false;
     }
 
-    std::cout << http_response.content() << std::endl;
-
+    std::cout << http_response.status() << std::endl;
     return true;
   }
+
+private:
+  webcc::RestClient rest_client_;
 };
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -147,13 +119,8 @@ void Help(const char* argv0) {
 
 std::string GetUserInput() {
   char input[256];
-  // std::size_t length = 0;
-  // do {
-    std::cout << ">> ";
-    std::cin.getline(input, 256);
-    // length = strlen(input);
-  // } while (length == 0);
-
+  std::cout << ">> ";
+  std::cin.getline(input, 256);
   return input;
 }
 
diff --git a/example/rest_book_server/book_services.cc b/example/rest_book_server/book_services.cc
index ed05116..be4795e 100644
--- a/example/rest_book_server/book_services.cc
+++ b/example/rest_book_server/book_services.cc
@@ -144,6 +144,7 @@ bool BookListService::Post(const std::string& request_content,
 ////////////////////////////////////////////////////////////////////////////////
 
 bool BookDetailService::Get(const std::vector<std::string>& url_sub_matches,
+                            const webcc::UrlQuery& query,
                             std::string* response_content) {
   if (url_sub_matches.size() != 1) {
     return false;
diff --git a/example/rest_book_server/book_services.h b/example/rest_book_server/book_services.h
index 0e74ca5..061dc56 100644
--- a/example/rest_book_server/book_services.h
+++ b/example/rest_book_server/book_services.h
@@ -32,6 +32,7 @@ class BookListService : public webcc::RestListService {
 class BookDetailService : public webcc::RestDetailService {
  protected:
   bool Get(const std::vector<std::string>& url_sub_matches,
+           const webcc::UrlQuery& query,
            std::string* response_content) final;
 
   bool Patch(const std::vector<std::string>& url_sub_matches,
diff --git a/src/webcc/CMakeLists.txt b/src/webcc/CMakeLists.txt
index b16d897..71a1847 100644
--- a/src/webcc/CMakeLists.txt
+++ b/src/webcc/CMakeLists.txt
@@ -2,8 +2,8 @@
 add_definitions(-DBOOST_ASIO_NO_DEPRECATED)
 
 set(SRCS
-	common.cc
-	common.h
+	globals.cc
+	globals.h
 	http_client.cc
 	http_client.h
 	http_message.cc
@@ -27,7 +27,12 @@ set(SRCS
 	logger.cc
 	logger.h
 	queue.h
-	rest_server.cc
+	rest_client.cc
+	rest_client.h
+	rest_request_handler.cc
+	rest_request_handler.h
+	rest_service_manager.cc
+	rest_service_manager.h
 	rest_server.h
 	rest_service.cc
 	rest_service.h
diff --git a/src/webcc/common.cc b/src/webcc/globals.cc
similarity index 93%
rename from src/webcc/common.cc
rename to src/webcc/globals.cc
index dfd219c..ce0d9e1 100644
--- a/src/webcc/common.cc
+++ b/src/webcc/globals.cc
@@ -1,4 +1,4 @@
-#include "webcc/common.h"
+#include "webcc/globals.h"
 
 namespace webcc {
 
@@ -63,13 +63,6 @@ const char* GetErrorMessage(Error error) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-const SoapNamespace kSoapEnvNamespace{
-  "soap",
-  "http://schemas.xmlsoap.org/soap/envelope/"
-};
-
-////////////////////////////////////////////////////////////////////////////////
-
 Parameter::Parameter(const std::string& key, const char* value)
     : key_(key), value_(value) {
 }
@@ -110,4 +103,8 @@ Parameter& Parameter::operator=(Parameter&& rhs) {
   return *this;
 }
 
+std::string Parameter::ToString() const {
+  return key_ + "=" + value_;
+}
+
 }  // namespace webcc
diff --git a/src/webcc/common.h b/src/webcc/globals.h
similarity index 59%
rename from src/webcc/common.h
rename to src/webcc/globals.h
index c5086b2..5431cc1 100644
--- a/src/webcc/common.h
+++ b/src/webcc/globals.h
@@ -1,17 +1,47 @@
-#ifndef WEBCC_COMMON_H_
-#define WEBCC_COMMON_H_
-
-// Common definitions.
+#ifndef WEBCC_GLOBALS_H_
+#define WEBCC_GLOBALS_H_
 
 #include <string>
 #include <vector>
 
 namespace webcc {
 
-////////////////////////////////////////////////////////////////////////////////
+// -----------------------------------------------------------------------------
+// Macros
+
+// Explicitly declare the assignment operator as deleted.
+#define DISALLOW_ASSIGN(TypeName) TypeName& operator=(const TypeName&) = delete;
+
+// Explicitly declare the copy constructor and assignment operator as deleted.
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&) = delete;      \
+  DISALLOW_ASSIGN(TypeName)
+
+// Explicitly declare all implicit constructors as deleted, namely the
+// default constructor, copy constructor and operator= functions.
+// This is especially useful for classes containing only static methods.
+#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \
+  TypeName() = delete;                           \
+  DISALLOW_COPY_AND_ASSIGN(TypeName)
+
+// Disallow copying a type, but provide default construction, move construction
+// and move assignment. Especially useful for move-only structs.
+#define MOVE_ONLY_WITH_DEFAULT_CONSTRUCTORS(TypeName) \
+  TypeName() = default;                               \
+  MOVE_ONLY_NO_DEFAULT_CONSTRUCTOR(TypeName)
+
+// Disallow copying a type, and only provide move construction and move
+// assignment. Especially useful for move-only structs.
+#define MOVE_ONLY_NO_DEFAULT_CONSTRUCTOR(TypeName) \
+  TypeName(TypeName&&) = default;                  \
+  TypeName& operator=(TypeName&&) = default;       \
+  DISALLOW_COPY_AND_ASSIGN(TypeName)
+
+// -----------------------------------------------------------------------------
+// Constants
 
 // Buffer size for sending HTTP request and receiving HTTP response.
-// TODO: Configurable for client and server separately.
+// TODO: Configurable
 const std::size_t kBufferSize = 1024;
 
 const std::size_t kInvalidLength = static_cast<std::size_t>(-1);
@@ -24,8 +54,6 @@ extern const std::string kHost;
 extern const std::string kTextXmlUtf8;
 extern const std::string kTextJsonUtf8;
 
-////////////////////////////////////////////////////////////////////////////////
-
 // HTTP methods (verbs) in string ("HEAD", "GET", etc.).
 // NOTE: Don't use enum to avoid converting back and forth.
 extern const std::string kHttpHead;
@@ -54,11 +82,9 @@ struct HttpStatus {
   };
 };
 
-////////////////////////////////////////////////////////////////////////////////
-
 // Error codes.
 enum Error {
-  kNoError = 0,  // OK
+  kNoError = 0,
 
   kHostResolveError,
   kEndpointConnectError,
@@ -83,31 +109,14 @@ enum Error {
 // Return a descriptive message for the given error code.
 const char* GetErrorMessage(Error error);
 
-////////////////////////////////////////////////////////////////////////////////
-
-// XML namespace name/url pair.
-// E.g., { "soap", "http://schemas.xmlsoap.org/soap/envelope/" }
-class SoapNamespace {
-public:
-  std::string name;
-  std::string url;
-
-  bool IsValid() const {
-    return !name.empty() && !url.empty();
-  }
-};
-
-// CSoap's default namespace for SOAP Envelope.
-extern const SoapNamespace kSoapEnvNamespace;
-
-////////////////////////////////////////////////////////////////////////////////
+// -----------------------------------------------------------------------------
 
 // Key-value parameter.
 class Parameter {
 public:
   Parameter() = default;
-  Parameter(const Parameter& rhs) = default;
-  Parameter& operator=(const Parameter& rhs) = default;
+  Parameter(const Parameter&) = default;
+  Parameter& operator=(const Parameter&) = default;
 
   Parameter(const std::string& key, const char* value);
   Parameter(const std::string& key, const std::string& value);
@@ -138,6 +147,9 @@ public:
     return value_.c_str();
   }
 
+  // Return "key=value" string.
+  std::string ToString() const;
+
 private:
   std::string key_;
   std::string value_;
@@ -145,4 +157,4 @@ private:
 
 }  // namespace webcc
 
-#endif  // WEBCC_COMMON_H_
+#endif  // WEBCC_GLOBALS_H_
diff --git a/src/webcc/http_async_client.cc b/src/webcc/http_async_client.cc
new file mode 100644
index 0000000..3f26649
--- /dev/null
+++ b/src/webcc/http_async_client.cc
@@ -0,0 +1,169 @@
+#include "webcc/http_async_client.h"
+
+#if WEBCC_DEBUG_OUTPUT
+#include <iostream>
+#endif
+
+#if 0
+#include "boost/asio.hpp"
+#else
+#include "boost/asio/connect.hpp"
+//#include "boost/asio/ip/tcp.hpp"
+#include "boost/asio/read.hpp"
+#include "boost/asio/write.hpp"
+#endif
+
+#include "webcc/http_response_parser.h"
+#include "webcc/http_request.h"
+#include "webcc/http_response.h"
+
+using boost::asio::ip::tcp;
+
+namespace webcc {
+
+HttpAsyncClient::HttpAsyncClient(boost::asio::io_context& io_context)
+    : socket_(io_context) {
+
+  resolver_.reset(new tcp::resolver(io_context));
+
+  response_.reset(new HttpResponse());
+  parser_.reset(new HttpResponseParser(response_.get()));
+}
+
+Error HttpAsyncClient::SendRequest(std::shared_ptr<HttpRequest> request,
+                                   HttpResponseHandler response_handler) {
+  request_ = request;
+
+  std::string port = request->port();
+  if (port.empty()) {
+    port = "80";
+  }
+
+  auto handler = std::bind(&HttpAsyncClient::HandleResolve,
+                           this,
+                           std::placeholders::_1,
+                           std::placeholders::_2);
+
+  resolver_->async_resolve(tcp::v4(), request->host(), port, handler);
+
+  return kNoError;
+}
+
+void HttpAsyncClient::HandleResolve(boost::system::error_code ec,
+                                    tcp::resolver::results_type results) {
+  if (ec) {
+    std::cerr << "Resolve: " << ec.message() << std::endl;
+    //  return kHostResolveError;
+  } else {
+    endpoints_ = results;
+    DoConnect(endpoints_.begin());
+  }
+}
+
+void HttpAsyncClient::DoConnect(tcp::resolver::results_type::iterator endpoint_it) {
+  if (endpoint_it != endpoints_.end()) {
+    socket_.async_connect(endpoint_it->endpoint(),
+                          std::bind(&HttpAsyncClient::HandleConnect,
+                          this,
+                          std::placeholders::_1,
+                          endpoint_it));
+  }
+}
+
+void HttpAsyncClient::HandleConnect(boost::system::error_code ec,
+                                    tcp::resolver::results_type::iterator endpoint_it) {
+  if (ec) {
+    // Will be here if the end point is v6.
+    std::cout << "Connect error: " << ec.message() << std::endl;
+    //  return kEndpointConnectError;
+
+    socket_.close();
+
+    // Try the next available endpoint.
+    DoConnect(++endpoint_it);
+  } else {
+    DoWrite();
+  }
+}
+
+// Send HTTP request.
+void HttpAsyncClient::DoWrite() {
+  boost::asio::async_write(socket_,
+                           request_->ToBuffers(),
+                           std::bind(&HttpAsyncClient::HandleWrite,
+                           this,
+                           std::placeholders::_1));
+}
+
+void HttpAsyncClient::HandleWrite(boost::system::error_code ec) {
+  if (ec) {
+    //return kSocketWriteError;
+    return;
+  }
+
+  DoRead();
+}
+
+void HttpAsyncClient::DoRead() {
+  socket_.async_read_some(boost::asio::buffer(buffer_),
+                          std::bind(&HttpAsyncClient::HandleRead,
+                          this,
+                          std::placeholders::_1,
+                          std::placeholders::_2));
+}
+
+void HttpAsyncClient::HandleRead(boost::system::error_code ec,
+                                 std::size_t length) {
+  if (ec || length == 0) {
+    //return kSocketReadError;
+    return;
+  }
+
+#if WEBCC_DEBUG_OUTPUT
+  // NOTE: the content XML might not be well formated.
+  std::cout.write(buffer_.data(), length);
+#endif
+
+  // Parse the response piece just read.
+  // If the content has been fully received, next time flag "finished_"
+  // will be set.
+  Error error = parser_->Parse(buffer_.data(), length);
+
+  if (error != kNoError) {
+    //return error;
+  }
+
+  if (parser_->finished()) {
+    return;
+  }
+
+  // Read and parse HTTP response.
+
+  // NOTE:
+  // We must stop trying to read once all content has been received,
+  // because some servers will block extra call to read_some().
+  //while (!parser_.finished()) {
+  //  size_t length = socket_.read_some(boost::asio::buffer(buffer_), ec);
+
+    //if (length == 0 || ec) {
+    //  return kSocketReadError;
+    //}
+
+    // Parse the response piece just read.
+    // If the content has been fully received, next time flag "finished_"
+    // will be set.
+    //Error error = parser_.Parse(buffer_.data(), length);
+
+    //if (error != kNoError) {
+    //  return error;
+    //}
+  //}
+
+//#if WEBCC_DEBUG_OUTPUT
+//  std::cout << std::endl;
+//  std::cout << "--- RESPONSE (PARSED) ---" << std::endl;
+//  std::cout << *response << std::endl;
+//#endif
+}
+
+}  // namespace webcc
diff --git a/src/webcc/http_async_client.h b/src/webcc/http_async_client.h
new file mode 100644
index 0000000..00004bf
--- /dev/null
+++ b/src/webcc/http_async_client.h
@@ -0,0 +1,62 @@
+#ifndef WEBCC_HTTP_ASYNC_CLIENT_H_
+#define WEBCC_HTTP_ASYNC_CLIENT_H_
+
+#include <array>
+
+#include "boost/smart_ptr/scoped_ptr.hpp"
+
+#include "boost/asio/io_context.hpp"
+#include "boost/asio/ip/tcp.hpp"
+
+#include "webcc/common.h"
+#include "webcc/http_response_parser.h"
+
+namespace webcc {
+
+class HttpRequest;
+class HttpResponse;
+
+typedef void(*HttpResponseHandler)(std::shared_ptr<HttpResponse>);
+
+class HttpAsyncClient {
+public:
+  HttpAsyncClient(boost::asio::io_context& io_context);
+
+  Error SendRequest(std::shared_ptr<HttpRequest> request,
+                    HttpResponseHandler response_handler);
+
+private:
+  void HandleResolve(boost::system::error_code ec,
+                     boost::asio::ip::tcp::resolver::results_type results);
+
+  void DoConnect(boost::asio::ip::tcp::resolver::results_type::iterator endpoint_it);
+
+  void HandleConnect(boost::system::error_code ec,
+                     boost::asio::ip::tcp::resolver::results_type::iterator endpoint_it);
+
+  void DoWrite();
+
+  void HandleWrite(boost::system::error_code ec);
+
+  void DoRead();
+
+  void HandleRead(boost::system::error_code ec, std::size_t length);
+
+private:
+  boost::asio::ip::tcp::socket socket_;
+
+  std::shared_ptr<HttpRequest> request_;
+
+  std::unique_ptr<boost::asio::ip::tcp::resolver> resolver_;
+  boost::asio::ip::tcp::resolver::results_type endpoints_;
+
+  std::array<char, kBufferSize> buffer_;
+
+  std::unique_ptr<HttpResponseParser> parser_;
+
+  std::shared_ptr<HttpResponse> response_;
+};
+
+}  // namespace webcc
+
+#endif  // WEBCC_HTTP_ASYNC_CLIENT_H_
diff --git a/src/webcc/http_client.cc b/src/webcc/http_client.cc
index 4645afa..089c80f 100644
--- a/src/webcc/http_client.cc
+++ b/src/webcc/http_client.cc
@@ -3,14 +3,9 @@
 #include "boost/date_time/posix_time/posix_time.hpp"
 #include "boost/lambda/bind.hpp"
 #include "boost/lambda/lambda.hpp"
-
-#if 0
-#include "boost/asio.hpp"
-#else
 #include "boost/asio/connect.hpp"
 #include "boost/asio/read.hpp"
 #include "boost/asio/write.hpp"
-#endif
 
 #include "webcc/logger.h"
 #include "webcc/http_request.h"
diff --git a/src/webcc/http_client.h b/src/webcc/http_client.h
index 22be370..8bd6bf8 100644
--- a/src/webcc/http_client.h
+++ b/src/webcc/http_client.h
@@ -5,10 +5,10 @@
 #include <memory>
 
 #include "boost/asio/deadline_timer.hpp"
-#include "boost/asio/ip/tcp.hpp"
 #include "boost/asio/io_context.hpp"
+#include "boost/asio/ip/tcp.hpp"
 
-#include "webcc/common.h"
+#include "webcc/globals.h"
 #include "webcc/http_response_parser.h"
 
 namespace webcc {
diff --git a/src/webcc/http_message.h b/src/webcc/http_message.h
index db4e315..fbb9f79 100644
--- a/src/webcc/http_message.h
+++ b/src/webcc/http_message.h
@@ -3,7 +3,8 @@
 
 #include <cassert>
 #include <string>
-#include "webcc/common.h"
+
+#include "webcc/globals.h"
 
 namespace webcc {
 
@@ -16,9 +17,6 @@ public:
 // Base class for HTTP request and response messages.
 class HttpMessage {
 public:
-  HttpMessage() = default;
-  HttpMessage(const HttpMessage&) = default;
-  HttpMessage& operator=(const HttpMessage&) = default;
   virtual ~HttpMessage() = default;
 
   const std::string& start_line() const {
diff --git a/src/webcc/http_parser.h b/src/webcc/http_parser.h
index bbab09b..89271cd 100644
--- a/src/webcc/http_parser.h
+++ b/src/webcc/http_parser.h
@@ -2,7 +2,8 @@
 #define WEBCC_HTTP_PARSER_H_
 
 #include <string>
-#include "webcc/common.h"
+
+#include "webcc/globals.h"
 
 namespace webcc {
 
@@ -15,9 +16,6 @@ public:
 
   virtual ~HttpParser() = default;
 
-  HttpParser(const HttpParser&) = delete;
-  HttpParser& operator=(const HttpParser&) = delete;
-
   bool finished() const {
     return finished_;
   }
@@ -53,6 +51,8 @@ protected:
   bool content_length_parsed_;
   bool header_parsed_;
   bool finished_;
+
+  DISALLOW_COPY_AND_ASSIGN(HttpParser);
 };
 
 }  // namespace webcc
diff --git a/src/webcc/http_request.h b/src/webcc/http_request.h
index 1891b35..00efb66 100644
--- a/src/webcc/http_request.h
+++ b/src/webcc/http_request.h
@@ -2,7 +2,9 @@
 #define WEBCC_HTTP_REQUEST_H_
 
 #include <string>
+
 #include "boost/asio/buffer.hpp"  // for const_buffer
+
 #include "webcc/http_message.h"
 
 namespace webcc {
@@ -12,10 +14,6 @@ class HttpRequest;
 std::ostream& operator<<(std::ostream& os, const HttpRequest& request);
 
 class HttpRequest : public HttpMessage {
-
-  friend std::ostream& operator<<(std::ostream& os,
-                                  const HttpRequest& request);
-
 public:
   HttpRequest() = default;
   HttpRequest(const HttpRequest&) = default;
@@ -47,8 +45,9 @@ public:
     return port_;
   }
 
-  // \param host Descriptive host name or numeric IP address.
-  // \param port Numeric port number, "80" will be used if it's empty.
+  // Set host name and port number.
+  // The |host| is a descriptive name or a numeric IP address. The |port| is
+  // a numeric number (e.g., "9000") and "80" will be used if it's empty.
   void SetHost(const std::string& host, const std::string& port);
 
   // Compose start line, etc.
@@ -64,6 +63,8 @@ public:
   std::string Dump() const;
 
 private:
+  friend std::ostream& operator<<(std::ostream& os, const HttpRequest& request);
+
   // HTTP method.
   std::string method_;
 
diff --git a/src/webcc/http_request_handler.cc b/src/webcc/http_request_handler.cc
index b0fbce5..e1a04ee 100644
--- a/src/webcc/http_request_handler.cc
+++ b/src/webcc/http_request_handler.cc
@@ -2,10 +2,10 @@
 
 #include <sstream>
 
-#include "webcc/logger.h"
-#include "webcc/common.h"
+#include "webcc/globals.h"
 #include "webcc/http_request.h"
 #include "webcc/http_response.h"
+#include "webcc/logger.h"
 
 namespace webcc {
 
diff --git a/src/webcc/http_request_handler.h b/src/webcc/http_request_handler.h
index f85bde6..491546f 100644
--- a/src/webcc/http_request_handler.h
+++ b/src/webcc/http_request_handler.h
@@ -18,13 +18,8 @@ class HttpResponse;
 // The common handler for all incoming requests.
 class HttpRequestHandler {
 public:
-  HttpRequestHandler(const HttpRequestHandler&) = delete;
-  HttpRequestHandler& operator=(const HttpRequestHandler&) = delete;
-
   HttpRequestHandler() = default;
-
-  virtual ~HttpRequestHandler() {
-  }
+  virtual ~HttpRequestHandler() = default;
 
   // Put the session into the queue.
   void Enqueue(HttpSessionPtr session);
@@ -41,9 +36,10 @@ private:
   // Called by the worker routine.
   virtual void HandleSession(HttpSessionPtr session) = 0;
 
-private:
   Queue<HttpSessionPtr> queue_;
   boost::thread_group workers_;
+
+  DISALLOW_COPY_AND_ASSIGN(HttpRequestHandler);
 };
 
 }  // namespace webcc
diff --git a/src/webcc/http_request_parser.h b/src/webcc/http_request_parser.h
index 4feb69b..3cd5807 100644
--- a/src/webcc/http_request_parser.h
+++ b/src/webcc/http_request_parser.h
@@ -16,7 +16,6 @@ public:
 private:
   Error ParseStartLine(const std::string& line) override;
 
-private:
   HttpRequest* request_;
 };
 
diff --git a/src/webcc/http_response.cc b/src/webcc/http_response.cc
index c74f321..68cdba9 100644
--- a/src/webcc/http_response.cc
+++ b/src/webcc/http_response.cc
@@ -1,4 +1,5 @@
 #include "webcc/http_response.h"
+
 #include <iostream>
 #include <sstream>
 
diff --git a/src/webcc/http_response.h b/src/webcc/http_response.h
index df1d736..95b6c7c 100644
--- a/src/webcc/http_response.h
+++ b/src/webcc/http_response.h
@@ -2,7 +2,9 @@
 #define WEBCC_HTTP_RESPONSE_H_
 
 #include <string>
+
 #include "boost/asio/buffer.hpp"  // for const_buffer
+
 #include "webcc/http_message.h"
 
 namespace webcc {
@@ -12,9 +14,6 @@ class HttpResponse;
 std::ostream& operator<<(std::ostream& os, const HttpResponse& response);
 
 class HttpResponse : public HttpMessage {
-  friend std::ostream& operator<<(std::ostream& os,
-                                  const HttpResponse& response);
-
 public:
   HttpResponse() = default;
   ~HttpResponse() override = default;
@@ -39,6 +38,9 @@ public:
   static HttpResponse Fault(HttpStatus::Enum status);
 
 private:
+  friend std::ostream& operator<<(std::ostream& os,
+                                  const HttpResponse& response);
+
   int status_ = HttpStatus::kOK;
 };
 
diff --git a/src/webcc/http_response_parser.cc b/src/webcc/http_response_parser.cc
index b3c7419..c6ae836 100644
--- a/src/webcc/http_response_parser.cc
+++ b/src/webcc/http_response_parser.cc
@@ -1,5 +1,7 @@
 #include "webcc/http_response_parser.h"
+
 #include "boost/lexical_cast.hpp"
+
 #include "webcc/http_response.h"
 
 namespace webcc {
diff --git a/src/webcc/http_server.cc b/src/webcc/http_server.cc
index b71281f..f9488f2 100644
--- a/src/webcc/http_server.cc
+++ b/src/webcc/http_server.cc
@@ -1,9 +1,9 @@
 #include "webcc/http_server.h"
 
-#include <signal.h>
+#include <csignal>
 
-#include "webcc/logger.h"
 #include "webcc/http_request_handler.h"
+#include "webcc/logger.h"
 #include "webcc/soap_service.h"
 #include "webcc/utility.h"
 
diff --git a/src/webcc/http_server.h b/src/webcc/http_server.h
index fa47ef7..07241ff 100644
--- a/src/webcc/http_server.h
+++ b/src/webcc/http_server.h
@@ -4,12 +4,11 @@
 #include <string>
 #include <vector>
 
-#include "boost/scoped_ptr.hpp"
-#include "boost/thread/thread.hpp"
-
 #include "boost/asio/io_context.hpp"
-#include "boost/asio/signal_set.hpp"
 #include "boost/asio/ip/tcp.hpp"
+#include "boost/asio/signal_set.hpp"
+#include "boost/scoped_ptr.hpp"
+#include "boost/thread/thread.hpp"
 
 #include "webcc/http_session.h"
 
diff --git a/src/webcc/http_session.cc b/src/webcc/http_session.cc
index 2a5fdb7..8f4dc30 100644
--- a/src/webcc/http_session.cc
+++ b/src/webcc/http_session.cc
@@ -5,8 +5,8 @@
 #include "boost/asio/write.hpp"
 #include "boost/date_time/posix_time/posix_time.hpp"
 
-#include "webcc/logger.h"
 #include "webcc/http_request_handler.h"
+#include "webcc/logger.h"
 
 namespace webcc {
 
diff --git a/src/webcc/http_session.h b/src/webcc/http_session.h
index 6136c22..6e3ccba 100644
--- a/src/webcc/http_session.h
+++ b/src/webcc/http_session.h
@@ -6,7 +6,7 @@
 
 #include "boost/asio/ip/tcp.hpp"  // for ip::tcp::socket
 
-#include "webcc/common.h"
+#include "webcc/globals.h"
 #include "webcc/http_request.h"
 #include "webcc/http_request_parser.h"
 #include "webcc/http_response.h"
diff --git a/src/webcc/queue.h b/src/webcc/queue.h
index 057f6de..a61a0d8 100644
--- a/src/webcc/queue.h
+++ b/src/webcc/queue.h
@@ -15,11 +15,11 @@ namespace webcc {
 template <typename T>
 class Queue {
 public:
-  Queue(const Queue& rhs) = delete;
-  Queue& operator=(const Queue& rhs) = delete;
-
   Queue() = default;
 
+  Queue(const Queue&) = delete;
+  Queue& operator=(const Queue&) = delete;
+
   T PopOrWait() {
     boost::unique_lock<boost::mutex> lock(mutex_);
 
diff --git a/src/webcc/rest_client.cc b/src/webcc/rest_client.cc
new file mode 100644
index 0000000..a6440b9
--- /dev/null
+++ b/src/webcc/rest_client.cc
@@ -0,0 +1,31 @@
+#include "webcc/rest_client.h"
+
+#include "webcc/http_client.h"
+#include "webcc/http_request.h"
+#include "webcc/http_response.h"
+
+namespace webcc {
+
+bool RestClient::Request(const std::string& method,
+                         const std::string& url,
+                         const std::string& content,
+                         HttpResponse* response) {
+  HttpRequest request;
+
+  request.set_method(method);
+  request.set_url(url);
+  request.SetHost(host_, port_);
+
+  if (!content.empty()) {
+    request.SetContent(content);
+  }
+
+  request.Build();
+
+  HttpClient http_client;
+  Error error = http_client.MakeRequest(request, response);
+
+  return error == kNoError;
+}
+
+}  // namespace webcc
diff --git a/src/webcc/rest_client.h b/src/webcc/rest_client.h
new file mode 100644
index 0000000..5186a2a
--- /dev/null
+++ b/src/webcc/rest_client.h
@@ -0,0 +1,56 @@
+#ifndef WEBCC_REST_CLIENT_H_
+#define WEBCC_REST_CLIENT_H_
+
+#include <string>
+
+#include "webcc/globals.h"
+
+namespace webcc {
+
+class HttpResponse;
+
+class RestClient {
+public:
+  RestClient(const std::string& host, const std::string& port)
+      : host_(host), port_(port) {
+  }
+
+  bool Get(const std::string& url, HttpResponse* response) {
+    return Request(kHttpGet, url, "", response);
+  }
+
+  bool Post(const std::string& url,
+            const std::string& content,
+            HttpResponse* response) {
+    return Request(kHttpPost, url, content, response);
+  }
+
+  bool Put(const std::string& url,
+           const std::string& content,
+           HttpResponse* response) {
+    return Request(kHttpPut, url, content, response);
+  }
+
+  bool Patch(const std::string& url,
+             const std::string& content,
+             HttpResponse* response) {
+    return Request(kHttpPatch, url, content, response);
+  }
+
+  bool Delete(const std::string& url, HttpResponse* response) {
+    return Request(kHttpDelete, url, "", response);
+  }
+
+private:
+  bool Request(const std::string& method,
+               const std::string& url,
+               const std::string& content,
+               HttpResponse* response);
+
+  std::string host_;
+  std::string port_;
+};
+
+}  // namespace webcc
+
+#endif  // WEBCC_REST_CLIENT_H_
diff --git a/src/webcc/rest_request_handler.cc b/src/webcc/rest_request_handler.cc
new file mode 100644
index 0000000..31e0192
--- /dev/null
+++ b/src/webcc/rest_request_handler.cc
@@ -0,0 +1,50 @@
+#include "webcc/rest_request_handler.h"
+
+#include "webcc/logger.h"
+#include "webcc/url.h"
+
+namespace webcc {
+
+bool RestRequestHandler::RegisterService(RestServicePtr service,
+                                         const std::string& url) {
+  return service_manager_.AddService(service, url);
+}
+
+void RestRequestHandler::HandleSession(HttpSessionPtr session) {
+  Url url(session->request().url(), true);
+
+  if (!url.IsValid()) {
+    session->SendResponse(HttpStatus::kBadRequest);
+    return;
+  }
+
+  std::vector<std::string> sub_matches;
+  RestServicePtr service = service_manager_.GetService(url.path(),
+                                                       &sub_matches);
+  if (!service) {
+    LOG_WARN("No service matches the URL: %s", url.path().c_str());
+    session->SendResponse(HttpStatus::kBadRequest);
+    return;
+  }
+
+  // TODO: Only for GET?
+  UrlQuery query;
+  Url::SplitQuery(url.query(), &query);
+
+  std::string content;
+  bool ok = service->Handle(session->request().method(),
+                            sub_matches,
+                            query,
+                            session->request().content(),
+                            &content);
+  if (!ok) {
+    // TODO: Could be other than kBadRequest.
+    session->SendResponse(HttpStatus::kBadRequest);
+    return;
+  }
+
+  session->SetResponseContent(std::move(content), kTextJsonUtf8);
+  session->SendResponse(HttpStatus::kOK);
+}
+
+}  // namespace webcc
diff --git a/src/webcc/rest_request_handler.h b/src/webcc/rest_request_handler.h
new file mode 100644
index 0000000..1e617a0
--- /dev/null
+++ b/src/webcc/rest_request_handler.h
@@ -0,0 +1,29 @@
+#ifndef WEBCC_REST_REQUEST_HANDLER_H_
+#define WEBCC_REST_REQUEST_HANDLER_H_
+
+// HTTP server handling REST requests.
+
+#include "webcc/http_request_handler.h"
+#include "webcc/rest_service_manager.h"
+
+namespace webcc {
+
+class RestRequestHandler : public HttpRequestHandler {
+public:
+  ~RestRequestHandler() override = default;
+
+  // Register a REST service to the given URL path.
+  // The URL should start with "/" and could be a regular expression or not.
+  // E.g., "/instances". "/instances/(\\d+)"
+  bool RegisterService(RestServicePtr service, const std::string& url);
+
+private:
+  void HandleSession(HttpSessionPtr session) override;
+
+private:
+  RestServiceManager service_manager_;
+};
+
+}  // namespace webcc
+
+#endif  // WEBCC_REST_REQUEST_HANDLER_H_
diff --git a/src/webcc/rest_server.cc b/src/webcc/rest_server.cc
deleted file mode 100644
index 61c558e..0000000
--- a/src/webcc/rest_server.cc
+++ /dev/null
@@ -1,114 +0,0 @@
-#include "webcc/rest_server.h"
-
-#include "webcc/logger.h"
-#include "webcc/url.h"
-
-namespace webcc {
-
-////////////////////////////////////////////////////////////////////////////////
-
-bool RestServiceManager::AddService(RestServicePtr service,
-                                    const std::string& url) {
-  assert(service);
-
-  ServiceItem item(service, url);
-
-  std::regex::flag_type flags = std::regex::ECMAScript | std::regex::icase;
-
-  try {
-    // Compile the regex.
-    item.url_regex.assign(url, flags);
-
-    service_items_.push_back(item);
-
-    return true;
-
-  } catch (std::regex_error& e) {
-    LOG_ERRO("URL is not a valid regular expression: %s", e.what());
-  }
-
-  return false;
-}
-
-RestServicePtr RestServiceManager::GetService(
-    const std::string& url,
-    std::vector<std::string>* sub_matches) {
-  assert(sub_matches != NULL);
-
-  for (ServiceItem& item : service_items_) {
-    std::smatch match;
-
-    if (std::regex_match(url, match, item.url_regex)) {
-      // Any sub-matches?
-      // NOTE: Start from 1 because match[0] is the whole string itself.
-      for (size_t i = 1; i < match.size(); ++i) {
-        sub_matches->push_back(match[i].str());
-      }
-
-      return item.service;
-    }
-  }
-
-  return RestServicePtr();
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
-bool RestRequestHandler::RegisterService(RestServicePtr service,
-                                         const std::string& url) {
-  return service_manager_.AddService(service, url);
-}
-
-void RestRequestHandler::HandleSession(HttpSessionPtr session) {
-  Url url(session->request().url());
-
-  if (!url.IsValid()) {
-    session->SendResponse(HttpStatus::kBadRequest);
-    return;
-  }
-
-  std::vector<std::string> sub_matches;
-  RestServicePtr service = service_manager_.GetService(url.path(), &sub_matches);
-  if (!service) {
-    LOG_WARN("No service matches the URL: %s", url.path().c_str());
-    session->SendResponse(HttpStatus::kBadRequest);
-    return;
-  }
-
-  // TODO: Only for GET?
-  UrlQuery query;
-  Url::SplitQuery(url.query(), &query);
-
-  std::string content;
-  bool ok = service->Handle(session->request().method(),
-                            sub_matches,
-                            query,
-                            session->request().content(),
-                            &content);
-  if (!ok) {
-    // TODO: Could be other than kBadRequest.
-    session->SendResponse(HttpStatus::kBadRequest);
-    return;
-  }
-
-  session->SetResponseContent(std::move(content), kTextJsonUtf8);
-  session->SendResponse(HttpStatus::kOK);
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
-RestServer::RestServer(unsigned short port, std::size_t workers)
-    : HttpServer(port, workers)
-    , request_handler_(new RestRequestHandler()) {
-}
-
-RestServer::~RestServer() {
-  delete request_handler_;
-}
-
-bool RestServer::RegisterService(RestServicePtr service,
-                                 const std::string& url) {
-  return request_handler_->RegisterService(service, url);
-}
-
-}  // namespace webcc
diff --git a/src/webcc/rest_server.h b/src/webcc/rest_server.h
index 112ab0c..bbdfeba 100644
--- a/src/webcc/rest_server.h
+++ b/src/webcc/rest_server.h
@@ -3,106 +3,36 @@
 
 // HTTP server handling REST requests.
 
-#include <regex>
-#include <string>
-#include <vector>
-
-#include "webcc/http_request_handler.h"
 #include "webcc/http_server.h"
+#include "webcc/rest_request_handler.h"
 #include "webcc/rest_service.h"
 
 namespace webcc {
 
-class Url;
-
-////////////////////////////////////////////////////////////////////////////////
-
-class RestServiceManager {
-public:
-  RestServiceManager() = default;
-  RestServiceManager(const RestServiceManager&) = delete;
-  RestServiceManager& operator=(const RestServiceManager&) = delete;
-
-  // Add a service and bind it with the given URL.
-  // The URL should start with "/" and could be a regular expression or not.
-  // E.g., "/instances". "/instances/(\\d+)"
-  bool AddService(RestServicePtr service, const std::string& url);
-
-  // Parameter 'sub_matches' is only available when the URL bound to the
-  // service is a regular expression and has sub-expressions.
-  // E.g., the URL bound to the service is "/instances/(\\d+)", now match
-  // "/instances/12345" against it, you will get one sub-match of "12345".
-  RestServicePtr GetService(const std::string& url,
-                            std::vector<std::string>* sub_matches);
-
-private:
-  class ServiceItem {
-  public:
-    ServiceItem(RestServicePtr _service, const std::string& _url)
-      : service(_service), url(_url) {
-    }
-
-    ServiceItem(const ServiceItem& rhs) = default;
-    ServiceItem& operator=(const ServiceItem& rhs) = default;
-
-    ServiceItem(ServiceItem&& rhs)
-        : url(std::move(rhs.url))
-        , url_regex(std::move(rhs.url_regex))
-        , service(rhs.service) {  // No move
-    }
-
-    RestServicePtr service;
-
-    // URL string, e.g., "/instances/(\\d+)".
-    std::string url;
-
-    // Compiled regex for URL string.
-    std::regex url_regex;
-  };
-
-  std::vector<ServiceItem> service_items_;
-};
-
-////////////////////////////////////////////////////////////////////////////////
-
-class RestRequestHandler : public HttpRequestHandler {
-public:
-  RestRequestHandler() = default;
-
-  // Register a REST service to the given URL path.
-  // The URL should start with "/" and could be a regular expression or not.
-  // E.g., "/instances". "/instances/(\\d+)"
-  bool RegisterService(RestServicePtr service, const std::string& url);
-
-private:
-  void HandleSession(HttpSessionPtr session) override;
-
-private:
-  RestServiceManager service_manager_;
-};
-
-////////////////////////////////////////////////////////////////////////////////
-
 class RestServer : public HttpServer {
 public:
-  RestServer(unsigned short port, std::size_t workers);
+  RestServer(unsigned short port, std::size_t workers)
+      : HttpServer(port, workers) {
+  }
 
-  ~RestServer() override;
+  ~RestServer() override = default;
 
   // Register a REST service to the given URL path.
   // The URL should start with "/" and could be a regular expression or not.
   // E.g., "/instances". "/instances/(\\d+)"
   // NOTE: Registering to the same URL multiple times is allowed, but only the
   //       last one takes effect.
-  bool RegisterService(RestServicePtr service, const std::string& url);
+  bool RegisterService(RestServicePtr service, const std::string& url) {
+    return request_handler_.RegisterService(service, url);
+  }
 
 private:
   HttpRequestHandler* GetRequestHandler() override {
-    return request_handler_;
+    return &request_handler_;
   }
 
 private:
-  RestRequestHandler* request_handler_;
+  RestRequestHandler request_handler_;
 };
 
 }  // namespace webcc
diff --git a/src/webcc/rest_service.cc b/src/webcc/rest_service.cc
index 1704513..4817443 100644
--- a/src/webcc/rest_service.cc
+++ b/src/webcc/rest_service.cc
@@ -1,4 +1,5 @@
 #include "webcc/rest_service.h"
+
 #include "webcc/logger.h"
 
 namespace webcc {
@@ -29,7 +30,7 @@ bool RestDetailService::Handle(const std::string& http_method,
                                const std::string& request_content,
                                std::string* response_content) {
   if (http_method == kHttpGet) {
-    return Get(url_sub_matches, response_content);
+    return Get(url_sub_matches, query, response_content);
   }
 
   if (http_method == kHttpPut) {
diff --git a/src/webcc/rest_service.h b/src/webcc/rest_service.h
index 1f193d5..39e483f 100644
--- a/src/webcc/rest_service.h
+++ b/src/webcc/rest_service.h
@@ -13,7 +13,7 @@
 #include <string>
 #include <vector>
 
-#include "webcc/common.h"
+#include "webcc/globals.h"
 
 namespace webcc {
 
@@ -28,12 +28,9 @@ public:
   }
 
   // Handle REST request, output the response.
-  // \param http_method GET, POST, etc.
-  // \param url_sub_matches The regex sub-matches in the URL,
-  //                        usually resource ID.
-  // \param query Query parameters in the URL.
-  // \param request_content Request JSON.
-  // \param response_content Output response JSON.
+  // The regex sub-matches of the URL (usually resource IDs) were stored in
+  // |url_sub_matches|. The |query| part of the URL is normally only for GET
+  // request. Both the request and response contents are JSON strings.
   virtual bool Handle(const std::string& http_method,
                       const std::vector<std::string>& url_sub_matches,
                       const UrlQuery& query,
@@ -79,6 +76,7 @@ class RestDetailService : public RestService {
 
  protected:
   virtual bool Get(const std::vector<std::string>& url_sub_matches,
+                   const UrlQuery& query,
                    std::string* response_content) {
     return false;
   }
diff --git a/src/webcc/rest_service_manager.cc b/src/webcc/rest_service_manager.cc
new file mode 100644
index 0000000..ad80dd9
--- /dev/null
+++ b/src/webcc/rest_service_manager.cc
@@ -0,0 +1,55 @@
+#include "webcc/rest_service_manager.h"
+
+#include <cassert>
+
+#include "webcc/logger.h"
+
+namespace webcc {
+
+bool RestServiceManager::AddService(RestServicePtr service,
+                                    const std::string& url) {
+  assert(service);
+
+  ServiceItem item(service, url);
+
+  std::regex::flag_type flags = std::regex::ECMAScript | std::regex::icase;
+
+  try {
+    // Compile the regex.
+    item.url_regex.assign(url, flags);
+
+    service_items_.push_back(item);
+
+    return true;
+
+  } catch (std::regex_error& e) {
+    LOG_ERRO("URL is not a valid regular expression: %s", e.what());
+  }
+
+  return false;
+}
+
+RestServicePtr RestServiceManager::GetService(
+    const std::string& url,
+    std::vector<std::string>* sub_matches) {
+
+  assert(sub_matches != NULL);
+
+  for (ServiceItem& item : service_items_) {
+    std::smatch match;
+
+    if (std::regex_match(url, match, item.url_regex)) {
+      // Any sub-matches?
+      // NOTE: Start from 1 because match[0] is the whole string itself.
+      for (size_t i = 1; i < match.size(); ++i) {
+        sub_matches->push_back(match[i].str());
+      }
+
+      return item.service;
+    }
+  }
+
+  return RestServicePtr();
+}
+
+}  // namespace webcc
diff --git a/src/webcc/rest_service_manager.h b/src/webcc/rest_service_manager.h
new file mode 100644
index 0000000..2bb896e
--- /dev/null
+++ b/src/webcc/rest_service_manager.h
@@ -0,0 +1,59 @@
+#ifndef WEBCC_REST_SERVICE_MANAGER_H_
+#define WEBCC_REST_SERVICE_MANAGER_H_
+
+#include <regex>
+#include <vector>
+
+#include "webcc/rest_service.h"
+
+namespace webcc {
+
+class RestServiceManager {
+public:
+  RestServiceManager() = default;
+
+  // Add a service and bind it with the given URL.
+  // The |url| should start with "/" and could be a regular expression or not.
+  // E.g., "/instances". "/instances/(\\d+)"
+  bool AddService(RestServicePtr service, const std::string& url);
+
+  // The |sub_matches| is only available when the |url| bound to the
+  // service is a regular expression and has sub-expressions.
+  // E.g., the URL bound to the service is "/instances/(\\d+)", now match
+  // "/instances/12345" against it, you will get one sub-match of "12345".
+  RestServicePtr GetService(const std::string& url,
+                            std::vector<std::string>* sub_matches);
+
+private:
+  class ServiceItem {
+  public:
+    ServiceItem(RestServicePtr _service, const std::string& _url)
+      : service(_service), url(_url) {
+    }
+
+    ServiceItem(const ServiceItem& rhs) = default;
+    ServiceItem& operator=(const ServiceItem& rhs) = default;
+
+    ServiceItem(ServiceItem&& rhs)
+        : url(std::move(rhs.url)),
+          url_regex(std::move(rhs.url_regex)),
+          service(rhs.service) {  // No move
+    }
+
+    RestServicePtr service;
+
+    // URL string, e.g., "/instances/(\\d+)".
+    std::string url;
+
+    // Compiled regex for URL string.
+    std::regex url_regex;
+  };
+
+  std::vector<ServiceItem> service_items_;
+
+  DISALLOW_COPY_AND_ASSIGN(RestServiceManager);
+};
+
+}  // namespace webcc
+
+#endif  // WEBCC_REST_SERVICE_MANAGER_H_
diff --git a/src/webcc/soap_client.h b/src/webcc/soap_client.h
index 1b98bee..28217a5 100644
--- a/src/webcc/soap_client.h
+++ b/src/webcc/soap_client.h
@@ -4,7 +4,8 @@
 #include <string>
 #include <vector>
 
-#include "webcc/common.h"
+#include "webcc/globals.h"
+#include "webcc/soap_message.h"
 
 namespace webcc {
 
diff --git a/src/webcc/soap_message.cc b/src/webcc/soap_message.cc
index bfb7fd9..a003112 100644
--- a/src/webcc/soap_message.cc
+++ b/src/webcc/soap_message.cc
@@ -1,10 +1,16 @@
 #include "webcc/soap_message.h"
 
 #include <cassert>
+
 #include "webcc/soap_xml.h"
 
 namespace webcc {
 
+const SoapNamespace kSoapEnvNamespace{
+  "soap",
+  "http://schemas.xmlsoap.org/soap/envelope/"
+};
+
 void SoapMessage::ToXml(std::string* xml_string) {
   assert(soapenv_ns_.IsValid() &&
          service_ns_.IsValid() &&
diff --git a/src/webcc/soap_message.h b/src/webcc/soap_message.h
index 23b25a1..6a581b2 100644
--- a/src/webcc/soap_message.h
+++ b/src/webcc/soap_message.h
@@ -2,14 +2,33 @@
 #define WEBCC_SOAP_MESSAGE_H_
 
 #include <string>
+
 #include "pugixml/pugixml.hpp"
-#include "webcc/common.h"
+
+#include "webcc/globals.h"
 
 namespace webcc {
 
+// XML namespace name/url pair.
+// E.g., { "soap", "http://schemas.xmlsoap.org/soap/envelope/" }
+class SoapNamespace {
+public:
+  std::string name;
+  std::string url;
+
+  bool IsValid() const {
+    return !name.empty() && !url.empty();
+  }
+};
+
+// CSoap's default namespace for SOAP Envelope.
+extern const SoapNamespace kSoapEnvNamespace;
+
 // Base class for SOAP request and response.
 class SoapMessage {
 public:
+  virtual ~SoapMessage() {}
+
   // E.g., set as kSoapEnvNamespace.
   void set_soapenv_ns(const SoapNamespace& soapenv_ns) {
     soapenv_ns_ = soapenv_ns;
@@ -34,8 +53,6 @@ public:
   bool FromXml(const std::string& xml_string);
 
 protected:
-  SoapMessage() = default;
-
   // Convert to SOAP body XML.
   virtual void ToXmlBody(pugi::xml_node xbody) = 0;
 
diff --git a/src/webcc/soap_request.cc b/src/webcc/soap_request.cc
index e209175..ea7332b 100644
--- a/src/webcc/soap_request.cc
+++ b/src/webcc/soap_request.cc
@@ -1,4 +1,5 @@
 #include "webcc/soap_request.h"
+
 #include "webcc/soap_xml.h"
 
 namespace webcc {
diff --git a/src/webcc/soap_request.h b/src/webcc/soap_request.h
index ccfd20a..7fca9cd 100644
--- a/src/webcc/soap_request.h
+++ b/src/webcc/soap_request.h
@@ -2,6 +2,7 @@
 #define WEBCC_SOAP_REQUEST_H_
 
 #include <vector>
+
 #include "webcc/soap_message.h"
 
 namespace webcc {
diff --git a/src/webcc/soap_server.cc b/src/webcc/soap_request_handler.cc
similarity index 71%
rename from src/webcc/soap_server.cc
rename to src/webcc/soap_request_handler.cc
index 7cfd917..3ef4345 100644
--- a/src/webcc/soap_server.cc
+++ b/src/webcc/soap_request_handler.cc
@@ -1,4 +1,4 @@
-#include "webcc/soap_server.h"
+#include "webcc/soap_request_handler.h"
 
 #include "webcc/logger.h"
 #include "webcc/soap_request.h"
@@ -6,8 +6,6 @@
 
 namespace webcc {
 
-////////////////////////////////////////////////////////////////////////////////
-
 bool SoapRequestHandler::RegisterService(SoapServicePtr service,
                                          const std::string& url) {
   assert(service);
@@ -55,20 +53,4 @@ SoapServicePtr SoapRequestHandler::GetServiceByUrl(const std::string& url) {
   return SoapServicePtr();
 }
 
-////////////////////////////////////////////////////////////////////////////////
-
-SoapServer::SoapServer(unsigned short port, std::size_t workers)
-    : HttpServer(port, workers)
-    , request_handler_(new SoapRequestHandler()) {
-}
-
-SoapServer::~SoapServer() {
-  delete request_handler_;
-}
-
-bool SoapServer::RegisterService(SoapServicePtr service,
-                                 const std::string& url) {
-  return request_handler_->RegisterService(service, url);
-}
-
 }  // namespace webcc
diff --git a/src/webcc/soap_request_handler.h b/src/webcc/soap_request_handler.h
new file mode 100644
index 0000000..e42ac1f
--- /dev/null
+++ b/src/webcc/soap_request_handler.h
@@ -0,0 +1,32 @@
+#ifndef WEBCC_SOAP_REQUEST_HANDLER_H_
+#define WEBCC_SOAP_REQUEST_HANDLER_H_
+
+#include <map>
+
+#include "webcc/http_request_handler.h"
+
+namespace webcc {
+
+class SoapRequestHandler : public HttpRequestHandler {
+public:
+  SoapRequestHandler() = default;
+  ~SoapRequestHandler() override = default;
+
+  // Register a SOAP service to the given URL path.
+  // The |url| path must start with "/", e.g., "/calculator".
+  // Registering to the same URL multiple times is allowed, but only the last
+  // one takes effect.
+  bool RegisterService(SoapServicePtr service, const std::string& url);
+
+private:
+  void HandleSession(HttpSessionPtr session) override;
+
+  SoapServicePtr GetServiceByUrl(const std::string& url);
+
+  typedef std::map<std::string, SoapServicePtr> UrlServiceMap;
+  UrlServiceMap url_service_map_;
+};
+
+}  // namespace webcc
+
+#endif  // WEBCC_SOAP_REQUEST_HANDLER_H_
diff --git a/src/webcc/soap_server.h b/src/webcc/soap_server.h
index 6cfe1a0..3327576 100644
--- a/src/webcc/soap_server.h
+++ b/src/webcc/soap_server.h
@@ -3,53 +3,29 @@
 
 // HTTP server handling SOAP requests.
 
-#include <map>
-#include <string>
-
-#include "webcc/http_request_handler.h"
+#include "webcc/soap_request_handler.h"
 #include "webcc/http_server.h"
 
 namespace webcc {
 
-////////////////////////////////////////////////////////////////////////////////
-
-class SoapRequestHandler : public HttpRequestHandler {
-public:
-  SoapRequestHandler() = default;
-
-  // Register a SOAP service to the given URL path.
-  // \url URL path, must start with "/". E.g., "/calculator".
-  // NOTE: Registering to the same URL multiple times is allowed, but only the
-  //       last one takes effect.
-  bool RegisterService(SoapServicePtr service, const std::string& url);
-
-private:
-  void HandleSession(HttpSessionPtr session) override;
-
-  SoapServicePtr GetServiceByUrl(const std::string& url);
-
-private:
-  typedef std::map<std::string, SoapServicePtr> UrlServiceMap;
-  UrlServiceMap url_service_map_;
-};
-
-////////////////////////////////////////////////////////////////////////////////
-
 class SoapServer : public HttpServer {
 public:
-  SoapServer(unsigned short port, std::size_t workers);
+  SoapServer(unsigned short port, std::size_t workers)
+      : HttpServer(port, workers) {
+  }
 
-  ~SoapServer() override;
+  ~SoapServer() override = default;
 
-  bool RegisterService(SoapServicePtr service, const std::string& url);
+  bool RegisterService(SoapServicePtr service, const std::string& url) {
+    return request_handler_.RegisterService(service, url);
+  }
 
 private:
   HttpRequestHandler* GetRequestHandler() override {
-    return request_handler_;
+    return &request_handler_;
   }
 
-private:
-  SoapRequestHandler* request_handler_;
+  SoapRequestHandler request_handler_;
 };
 
 }  // namespace webcc
diff --git a/src/webcc/soap_service.h b/src/webcc/soap_service.h
index 0cd3d00..d108442 100644
--- a/src/webcc/soap_service.h
+++ b/src/webcc/soap_service.h
@@ -2,7 +2,8 @@
 #define WEBCC_SOAP_SERVICE_H_
 
 #include <memory>
-#include "webcc/common.h"
+
+#include "webcc/globals.h"
 
 namespace webcc {
 
@@ -12,8 +13,7 @@ class SoapResponse;
 // Base class for your SOAP service.
 class SoapService {
 public:
-  virtual ~SoapService() {
-  }
+  virtual ~SoapService() = default;
 
   // Handle SOAP request, output the response.
   virtual bool Handle(const SoapRequest& soap_request,
diff --git a/src/webcc/soap_xml.cc b/src/webcc/soap_xml.cc
index b6c49ac..c7e2506 100644
--- a/src/webcc/soap_xml.cc
+++ b/src/webcc/soap_xml.cc
@@ -3,8 +3,7 @@
 namespace webcc {
 namespace soap_xml {
 
-void SplitName(const pugi::xml_node& xnode,
-               std::string* prefix,
+void SplitName(const pugi::xml_node& xnode, std::string* prefix,
                std::string* name) {
   std::string full_name = xnode.name();
 
@@ -39,14 +38,12 @@ std::string GetNameNoPrefix(const pugi::xml_node& xnode) {
   return name;
 }
 
-pugi::xml_node AddChild(pugi::xml_node& xnode,
-                        const std::string& ns,
+pugi::xml_node AddChild(pugi::xml_node& xnode, const std::string& ns,
                         const std::string& name) {
   return xnode.append_child((ns + ":" + name).c_str());
 }
 
-pugi::xml_node GetChild(pugi::xml_node& xnode,
-                        const std::string& ns,
+pugi::xml_node GetChild(pugi::xml_node& xnode, const std::string& ns,
                         const std::string& name) {
   return xnode.child((ns + ":" + name).c_str());
 }
@@ -72,28 +69,23 @@ pugi::xml_node GetChildNoNS(pugi::xml_node& xnode, const std::string& name) {
   return pugi::xml_node();
 }
 
-void AddAttr(pugi::xml_node& xnode,
-             const std::string& ns,
-             const std::string& name,
-             const std::string& value) {
+void AddAttr(pugi::xml_node& xnode, const std::string& ns,
+             const std::string& name, const std::string& value) {
   std::string ns_name = ns + ":" + name;
   xnode.append_attribute(ns_name.c_str()) = value.c_str();
 }
 
-void AddNSAttr(pugi::xml_node& xnode,
-               const std::string& ns_name,
+void AddNSAttr(pugi::xml_node& xnode, const std::string& ns_name,
                const std::string& ns_url) {
   AddAttr(xnode, "xmlns", ns_name, ns_url);
 }
 
-std::string GetNSAttr(pugi::xml_node& xnode,
-                      const std::string& ns_name) {
+std::string GetNSAttr(pugi::xml_node& xnode, const std::string& ns_name) {
   std::string attr_name = "xmlns:" + ns_name;
   return xnode.attribute(attr_name.c_str()).as_string();
 }
 
-bool PrettyPrint(std::ostream& os,
-                 const std::string& xml_string,
+bool PrettyPrint(std::ostream& os, const std::string& xml_string,
                  const char* indent) {
   pugi::xml_document xdoc;
   if (!xdoc.load_string(xml_string.c_str())) {
diff --git a/src/webcc/soap_xml.h b/src/webcc/soap_xml.h
index b7cd12b..0664ba4 100644
--- a/src/webcc/soap_xml.h
+++ b/src/webcc/soap_xml.h
@@ -1,19 +1,19 @@
 #ifndef WEBCC_SOAP_XML_H_
 #define WEBCC_SOAP_XML_H_
 
-// XML utilities.
+// XML helpers for SOAP messages.
 
 #include <string>
+
 #include "pugixml/pugixml.hpp"
 
 namespace webcc {
 namespace soap_xml {
 
 // Split the node name into namespace prefix and real name.
-// E.g., if the node name is "soapenv:Envelope", it will be splited to
+// E.g., if the node name is "soapenv:Envelope", it will be splitted to
 // "soapenv" and "Envelope".
-void SplitName(const pugi::xml_node& xnode,
-               std::string* prefix = NULL,
+void SplitName(const pugi::xml_node& xnode, std::string* prefix = NULL,
                std::string* name = NULL);
 
 // Get the namespace prefix from node name.
@@ -26,38 +26,31 @@ std::string GetNameNoPrefix(const pugi::xml_node& xnode);
 // Add a child with the given name which is prefixed by a namespace.
 // E.g., AppendChild(xnode, "soapenv", "Envelope") will append a child with
 // name "soapenv:Envelope".
-pugi::xml_node AddChild(pugi::xml_node& xnode,
-                        const std::string& ns,
+pugi::xml_node AddChild(pugi::xml_node& xnode, const std::string& ns,
                         const std::string& name);
 
-pugi::xml_node GetChild(pugi::xml_node& xnode,
-                        const std::string& ns,
+pugi::xml_node GetChild(pugi::xml_node& xnode, const std::string& ns,
                         const std::string& name);
 
 // TODO: Remove
-pugi::xml_node GetChildNoNS(pugi::xml_node& xnode,
-                            const std::string& name);
+pugi::xml_node GetChildNoNS(pugi::xml_node& xnode, const std::string& name);
 
 // Add an attribute with the given name which is prefixed by a namespace.
-void AddAttr(pugi::xml_node& xnode,
-             const std::string& ns,
-             const std::string& name,
-             const std::string& value);
+void AddAttr(pugi::xml_node& xnode, const std::string& ns,
+             const std::string& name, const std::string& value);
 
 // Append "xmlns" attribute.
 // E.g., if the namespace is
 //   { "soapenv", "http://schemas.xmlsoap.org/soap/envelope/" }
 // the attribute added will be
 //   xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
-void AddNSAttr(pugi::xml_node& xnode,
-               const std::string& ns_name,
+void AddNSAttr(pugi::xml_node& xnode, const std::string& ns_name,
                const std::string& ns_url);
 
 // Get namespace attribute value.
 // E.g., if the given namespace name is "soapenv", the value of
 // attribute "xmlns:soapenv" will be returned.
-std::string GetNSAttr(pugi::xml_node& xnode,
-                      const std::string& ns_name);
+std::string GetNSAttr(pugi::xml_node& xnode, const std::string& ns_name);
 
 // An XML writer writing to a referenced string.
 // Example:
@@ -68,12 +61,11 @@ std::string GetNSAttr(pugi::xml_node& xnode,
 //   xdoc.save(writer, "\t", pugi::format_default, pugi::encoding_utf8);
 class XmlStrRefWriter : public pugi::xml_writer {
 public:
-  explicit XmlStrRefWriter(std::string* result)
-      : result_(result) {
+  explicit XmlStrRefWriter(std::string* result) : result_(result) {
     result_->clear();
   }
 
-  virtual void write(const void* data, size_t size) override {
+  void write(const void* data, size_t size) override {
     result_->append(static_cast<const char*>(data), size);
   }
 
@@ -82,8 +74,7 @@ private:
 };
 
 // Print the XML string to output stream in pretty format.
-bool PrettyPrint(std::ostream& os,
-                 const std::string& xml_string,
+bool PrettyPrint(std::ostream& os, const std::string& xml_string,
                  const char* indent = "\t");
 
 }  // namespace soap_xml
diff --git a/src/webcc/url.cc b/src/webcc/url.cc
index a8ecba5..54c322c 100644
--- a/src/webcc/url.cc
+++ b/src/webcc/url.cc
@@ -6,13 +6,78 @@
 namespace webcc {
 
 ////////////////////////////////////////////////////////////////////////////////
+// Helper functions to decode URL string.
+
+// Convert a hex character digit to a decimal character value.
+static bool HexToDecimal(char hex, int* decimal) {
+  if (hex >= '0' && hex <= '9') {
+    *decimal = hex - '0';
+  } else if (hex >= 'A' && hex <= 'F') {
+    *decimal = 10 + (hex - 'A');
+  } else if (hex >= 'a' && hex <= 'f') {
+    *decimal = 10 + (hex - 'a');
+  } else {
+    return false;
+  }
+  return true;
+}
+
+static bool Decode(const std::string& encoded, std::string* raw) {
+  for (auto iter = encoded.begin(); iter != encoded.end(); ++iter) {
+    if (*iter == '%') {
+      if (++iter == encoded.end()) {
+        // Invalid URI string, two hexadecimal digits must follow '%'.
+        return false;
+      }
+
+      int h_decimal = 0;
+      if (!HexToDecimal(*iter, &h_decimal)) {
+        return false;
+      }
+
+      if (++iter == encoded.end()) {
+        // Invalid URI string, two hexadecimal digits must follow '%'.
+        return false;
+      }
+
+      int l_decimal = 0;
+      if (!HexToDecimal(*iter, &l_decimal)) {
+        return false;
+      }
+
+      raw->push_back(static_cast<char>((h_decimal << 4) + l_decimal));
+
+    } else if (*iter > 127 || *iter < 0) {
+      // Invalid encoded URI string, must be entirely ASCII.
+      return false;
+    } else {
+      raw->push_back(*iter);
+    }
+  }
+
+  return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+UrlQuery::UrlQuery(const std::map<std::string, std::string>& map) {
+  for (auto& pair : map) {
+    Add(pair.first, pair.second);
+  }
+}
 
 void UrlQuery::Add(std::string&& key, std::string&& value) {
-  if (!HasKey(key)) {
+  if (!Has(key)) {
     parameters_.push_back({ std::move(key), std::move(value) });
   }
 }
 
+void UrlQuery::Add(const std::string& key, const std::string& value) {
+  if (!Has(key)) {
+    parameters_.push_back({ key, value });
+  }
+}
+
 void UrlQuery::Remove(const std::string& key) {
   auto it = Find(key);
   if (it != parameters_.end()) {
@@ -20,16 +85,31 @@ void UrlQuery::Remove(const std::string& key) {
   }
 }
 
-const std::string& UrlQuery::GetValue(const std::string& key) const {
-  static const std::string kEmptyValue;
-
+const std::string& UrlQuery::Get(const std::string& key) const {
   auto it = Find(key);
   if (it != parameters_.end()) {
     return it->value();
   }
+
+  static const std::string kEmptyValue;
   return kEmptyValue;
 }
 
+std::string UrlQuery::ToString() const {
+  if (parameters_.empty()) {
+    return "";
+  }
+
+  std::string str = parameters_[0].ToString();
+
+  for (std::size_t i = 1; i < parameters_.size(); ++i) {
+    str += "&";
+    str += parameters_[i].ToString();
+  }
+
+  return str;
+}
+
 UrlQuery::ConstIterator UrlQuery::Find(const std::string& key) const {
   return std::find_if(parameters_.begin(),
                       parameters_.end(),
@@ -38,13 +118,18 @@ UrlQuery::ConstIterator UrlQuery::Find(const std::string& key) const {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-Url::Url(const std::string& str) {
-  std::size_t pos = str.find('?');
-  if (pos == std::string::npos) {
-    path_ = str;
+Url::Url(const std::string& str, bool decode) {
+  if (!decode || str.find('%') == std::string::npos) {
+    Init(str);
+    return;
+  }
+
+  std::string decoded;
+  if (Decode(str, &decoded)) {
+    Init(decoded);
   } else {
-    path_ = str.substr(0, pos);
-    query_ = str.substr(pos + 1);
+    // TODO: Exception?
+    Init(str);
   }
 }
 
@@ -103,4 +188,14 @@ void Url::SplitQuery(const std::string& str, UrlQuery* query) {
   }
 }
 
+void Url::Init(const std::string& str) {
+  std::size_t pos = str.find('?');
+  if (pos == std::string::npos) {
+    path_ = str;
+  } else {
+    path_ = str.substr(0, pos);
+    query_ = str.substr(pos + 1);
+  }
+}
+
 }  // namespace webcc
diff --git a/src/webcc/url.h b/src/webcc/url.h
index 2c61306..71aa9ec 100644
--- a/src/webcc/url.h
+++ b/src/webcc/url.h
@@ -11,27 +11,44 @@
 #include <string>
 #include <vector>
 
-#include "webcc/common.h"
+#include "webcc/globals.h"
 
 namespace webcc {
 
-////////////////////////////////////////////////////////////////////////////////
+// -----------------------------------------------------------------------------
 
 // URL query parameters.
 class UrlQuery {
 public:
   typedef std::vector<Parameter> Parameters;
 
+  UrlQuery() = default;
+
+  // Construct from key-value pairs.
+  explicit UrlQuery(const std::map<std::string, std::string>& map);
+
+  void Add(const std::string& key, const std::string& value);
+
   void Add(std::string&& key, std::string&& value);
 
   void Remove(const std::string& key);
 
-  const std::string& GetValue(const std::string& key) const;
+  // Get a value by key.
+  // Return empty string if the key doesn't exist.
+  const std::string& Get(const std::string& key) const;
 
-  bool HasKey(const std::string& key) const {
+  bool Has(const std::string& key) const {
     return Find(key) != parameters_.end();
   }
 
+  bool IsEmpty() const {
+    return parameters_.empty();
+  }
+
+  // Return key-value pairs concatenated by '&'.
+  // E.g., "item=12731&color=blue&size=large".
+  std::string ToString() const;
+
 private:
   typedef Parameters::const_iterator ConstIterator;
   ConstIterator Find(const std::string& key) const;
@@ -40,13 +57,12 @@ private:
   Parameters parameters_;
 };
 
-////////////////////////////////////////////////////////////////////////////////
+// -----------------------------------------------------------------------------
 
 class Url {
 public:
-  typedef std::map<std::string, std::string> Query;
-
-  Url(const std::string& str);
+  Url() = default;
+  Url(const std::string& str, bool decode);
 
   bool IsValid() const;
 
@@ -73,6 +89,8 @@ public:
   static void SplitQuery(const std::string& str, UrlQuery* query);
 
 private:
+  void Init(const std::string& str);
+
   std::string path_;
   std::string query_;
 };
diff --git a/src/webcc/utility.cc b/src/webcc/utility.cc
index e2e2dd3..c0c24d0 100644
--- a/src/webcc/utility.cc
+++ b/src/webcc/utility.cc
@@ -1,4 +1,5 @@
 #include "webcc/utility.h"
+
 #include <iostream>
 
 using tcp = boost::asio::ip::tcp;
diff --git a/unittest/rest_service_manager_test.cc b/unittest/rest_service_manager_test.cc
index 2ea792e..32a9734 100644
--- a/unittest/rest_service_manager_test.cc
+++ b/unittest/rest_service_manager_test.cc
@@ -1,10 +1,8 @@
-#include "webcc/rest_server.h"
+#include "webcc/rest_service_manager.h"
 #include "gtest/gtest.h"
 
 using namespace webcc;
 
-////////////////////////////////////////////////////////////////////////////////
-
 class TestRestService : public RestService {
 public:
   bool Handle(const std::string& http_method,
@@ -16,8 +14,6 @@ public:
   }
 };
 
-////////////////////////////////////////////////////////////////////////////////
-
 TEST(RestServiceManager, URL_RegexBasic) {
   RestServiceManager service_manager;