diff --git a/example/rest_book_client/CMakeLists.txt b/example/rest_book_client/CMakeLists.txt
index d381c00..f4416c9 100644
--- a/example/rest_book_client/CMakeLists.txt
+++ b/example/rest_book_client/CMakeLists.txt
@@ -6,5 +6,5 @@ file(GLOB SRCS *.cc *.h)
 
 add_executable(rest_book_client ${SRCS})
 
-target_link_libraries(rest_book_client webcc ${Boost_LIBRARIES})
+target_link_libraries(rest_book_client webcc jsoncpp ${Boost_LIBRARIES})
 target_link_libraries(rest_book_client "${CMAKE_THREAD_LIBS_INIT}")
diff --git a/example/rest_book_client/main.cc b/example/rest_book_client/main.cc
index 565ce76..24b9132 100644
--- a/example/rest_book_client/main.cc
+++ b/example/rest_book_client/main.cc
@@ -1,87 +1,209 @@
 #include <iostream>
 
+#include "boost/algorithm/string.hpp"
+#include "json/json.h"  // jsoncpp
+
 #include "webcc/http_client.h"
 #include "webcc/http_request.h"
 #include "webcc/http_response.h"
 
-class BookListClient {
+////////////////////////////////////////////////////////////////////////////////
+
+class BookClientBase {
 public:
-  BookListClient() {
-    host_ = "localhost";
-    port_ = "8080";
+  BookClientBase(const std::string& host, const std::string& port)
+      : host_(host), port_(port) {
   }
 
-  bool ListBooks() {
+  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(webcc::kHttpGet);
-    http_request.set_url("/books");
+    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::HttpResponse http_response;
-
     webcc::HttpClient http_client;
-    webcc::Error error = http_client.SendRequest(http_request, &http_response);
-
-    if (error != webcc::kNoError) {
-      return false;
-    }
-
-    std::cout << "Book list: " << std::endl
-              << http_response.content() << std::endl;
+    webcc::Error error = http_client.SendRequest(http_request, http_response);
 
-    return true;
+    return error == webcc::kNoError;
   }
 
-private:
+protected:
   std::string host_;
   std::string port_;
 };
 
-class BookDetailClient {
+////////////////////////////////////////////////////////////////////////////////
+
+class BookListClient : public BookClientBase {
 public:
-  BookDetailClient() {
-    host_ = "localhost";
-    port_ = "8080";
+  BookListClient(const std::string& host, const std::string& port)
+      : BookClientBase(host, port) {
   }
 
-  bool GetBook(const std::string& id) {
-    webcc::HttpRequest http_request;
+  bool ListBooks() {
+    webcc::HttpResponse http_response;
+    if (!Request(webcc::kHttpGet, "/books", "", &http_response)) {
+      return false;
+    }
 
-    http_request.set_method(webcc::kHttpGet);
-    http_request.set_url("/books/" + id);
-    http_request.SetHost(host_, port_);
+    std::cout << http_response.content() << std::endl;
 
-    http_request.Build();
+    return true;
+  }
 
-    webcc::HttpResponse http_response;
+  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;
 
-    webcc::HttpClient http_client;
-    webcc::Error error = http_client.SendRequest(http_request, &http_response);
+    Json::StreamWriterBuilder builder;
+    std::string book_json = Json::writeString(builder, root);
 
-    if (error != webcc::kNoError) {
+    webcc::HttpResponse http_response;
+    if (!Request(webcc::kHttpPost, "/books", book_json, &http_response)) {
       return false;
     }
 
-    std::cout << "Book: " << id << std::endl
-              << http_response.content() << std::endl;
+    std::cout << http_response.status() << std::endl;
 
     return true;
   }
+};
 
-private:
-  std::string host_;
-  std::string port_;
+////////////////////////////////////////////////////////////////////////////////
+
+class BookDetailClient : public BookClientBase {
+public:
+  BookDetailClient(const std::string& host, const std::string& port)
+      : BookClientBase(host, port) {
+  }
+
+  bool GetBook(const std::string& id) {
+    webcc::HttpResponse http_response;
+    if (!Request(webcc::kHttpGet, "/books/" + id, "", &http_response)) {
+      return false;
+    }
+
+    std::cout << http_response.content() << std::endl;
+
+    return true;
+  }
 };
 
-int main() {
-  BookListClient book_list_client;
-  book_list_client.ListBooks();
+////////////////////////////////////////////////////////////////////////////////
+
+std::string g_host;
+std::string g_port;
+
+void ListBooks() {
+  std::cout << "List books" << std::endl;
+
+  BookListClient client(g_host, g_port);
+
+  client.ListBooks();
+}
+
+void CreateBook(const std::string& id,
+                const std::string& title,
+                double price) {
+  std::cout << "Create book: " <<  id << " " << title << " " << price << std::endl;
+
+  BookListClient client(g_host, g_port);
+
+  client.CreateBook(id, title, price);
+}
+
+void Help(const char* argv0) {
+  std::cout << "Usage: " << argv0 << " <host> <port>" << std::endl;
+  std::cout << "  E.g.," << std::endl;
+  std::cout << "    " << argv0 << " localhost 8080" << std::endl;
+}
+
+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);
+
+  return input;
+}
+
+int main(int argc, char* argv[]) {
+  if (argc != 3) {
+    Help(argv[0]);
+    return 1;
+  }
+
+  g_host = argv[1];
+  g_port = argv[2];
+
+  // Type commands to execute actions.
+  // Commands: list, create, update, remove
+  // Examples:
+  //   >> list
+  //   >> create 1 { "title": "1984", "price": 12.3 }
+  //   >> detail 1
+  //   >> update 1 { "price": 32 }
+  //   >> delete 1
+
+  while (true) {
+    std::string input = GetUserInput();
+    boost::trim(input);
+
+    std::string command;
+    std::size_t i = input.find(' ');
+    if (i == std::string::npos) {
+      command = input;
+    } else {
+      command = input.substr(0, i);
+    }
+
+    if (command == "exit") {
+      break;
+    }
+
+    if (command == "list") {
+      ListBooks();
+      continue;
+    }
+
+    ++i;
+
+    std::size_t j = input.find(' ', i);
+    std::string id = input.substr(i, j - i);
+    i = j + 1;
+
+    if (command == "create") {
+      std::string json = input.substr(i);
+      std::cout << "json:" << json << std::endl;
+
+      Json::Value root;
+      Json::CharReaderBuilder builder;
+      std::string errs;
+      if (Json::parseFromStream(builder, std::stringstream(json), &root, &errs)) {
+        CreateBook(id, root["title"].asString(), root["price"].asDouble());
+      } else {
+        std::cerr << errs << std::endl;
+      }
+    }
+  }
 
-  BookDetailClient book_detail_client;
-  book_detail_client.GetBook("1");
+  //BookDetailClient book_detail_client(host, port);
+  //book_detail_client.GetBook("1");
 
   return 0;
 }
diff --git a/example/rest_book_server/book_services.cc b/example/rest_book_server/book_services.cc
index cfb2a85..ac77c51 100644
--- a/example/rest_book_server/book_services.cc
+++ b/example/rest_book_server/book_services.cc
@@ -1,6 +1,7 @@
 #include "book_services.h"
 
 #include <list>
+#include <iostream>
 #include "boost/lexical_cast.hpp"
 #include "json/json.h"  // jsoncpp
 
@@ -28,16 +29,16 @@ public:
   }
 };
 
+std::ostream& operator<<(std::ostream& os, const Book& book) {
+  os << "{ " << book.id << ", " << book.title << ", " << book.price << " }";
+  return os;
+}
+
 static const Book kNullBook{};
 
 class BookStore {
 public:
-  BookStore() {
-    // Prepare test data.
-    books_.push_back({ "1", "Title1", 11.1 });
-    books_.push_back({ "2", "Title2", 22.2 });
-    books_.push_back({ "3", "Title3", 33.3 });
-  }
+  BookStore() = default;
 
   const std::list<Book>& books() const {
     return books_;
@@ -87,16 +88,39 @@ bool BookListService::Handle(const std::string& http_method,
                              const std::string& request_content,
                              std::string* response_content) {
   if (http_method == webcc::kHttpGet) {
+    // Return all books as a JSON array.
+
     Json::Value root(Json::arrayValue);
     for (const Book& book : g_book_store.books()) {
       root.append(book.ToJson());
     }
 
-    Json::StreamWriterBuilder wbuilder;
-    *response_content = Json::writeString(wbuilder, root);
+    Json::StreamWriterBuilder builder;
+    *response_content = Json::writeString(builder, root);
+
     return true;
   }
 
+  if (http_method == webcc::kHttpPost) {
+    // Add a new book.
+
+    Json::Value root;
+    Json::CharReaderBuilder builder;
+    std::stringstream stream(request_content);
+    std::string errs;
+    if (!Json::parseFromStream(builder, stream, &root, &errs)) {
+      std::cerr << errs << std::endl;
+      return false;
+    }
+
+    Book book;
+    book.id = root["id"].asString();
+    book.title = root["title"].asString();
+    book.price = root["price"].asDouble();
+
+    return g_book_store.AddBook(book);
+  }
+
   return false;
 }
 
@@ -119,8 +143,8 @@ bool BookDetailService::Handle(const std::string& http_method,
       return false;
     }
 
-    Json::StreamWriterBuilder wbuilder;
-    *response_content = Json::writeString(wbuilder, book.ToJson());
+    Json::StreamWriterBuilder builder;
+    *response_content = Json::writeString(builder, book.ToJson());
 
     return true;
 
diff --git a/src/webcc/http_message.h b/src/webcc/http_message.h
index 5056ee5..db4e315 100644
--- a/src/webcc/http_message.h
+++ b/src/webcc/http_message.h
@@ -43,30 +43,20 @@ public:
     SetHeader(kContentType, content_type);
   }
 
-  void SetContentLength(std::size_t content_length) {
-    content_length_ = content_length;
-    SetHeader(kContentLength, std::to_string(content_length));
-  }
-
-  // Use move semantics to avoid copy.
-  void set_content(std::string&& content) {
+  void SetContent(std::string&& content) {
     content_ = std::move(content);
+    SetContentLength(content_.size());
   }
 
-  void AppendContent(const char* data, std::size_t count) {
-    content_.append(data, count);
-  }
-
-  void AppendContent(const std::string& data) {
-    content_.append(data);
-  }
-
-  bool IsContentFull() const {
-    return IsContentLengthValid() && content_.length() >= content_length_;
+  void SetContent(const std::string& content) {
+    content_ = content;
+    SetContentLength(content_.size());
   }
 
-  bool IsContentLengthValid() const {
-    return content_length_ != kInvalidLength;
+private:
+  void SetContentLength(std::size_t content_length) {
+    content_length_ = content_length;
+    SetHeader(kContentLength, std::to_string(content_length));
   }
 
 protected:
diff --git a/src/webcc/http_parser.cc b/src/webcc/http_parser.cc
index 8e62c0a..caa3538 100644
--- a/src/webcc/http_parser.cc
+++ b/src/webcc/http_parser.cc
@@ -9,6 +9,7 @@ namespace webcc {
 
 HttpParser::HttpParser(HttpMessage* message)
     : message_(message)
+    , content_length_(kInvalidLength)
     , start_line_parsed_(false)
     , content_length_parsed_(false)
     , header_parsed_(false)
@@ -18,11 +19,11 @@ HttpParser::HttpParser(HttpMessage* message)
 Error HttpParser::Parse(const char* data, std::size_t len) {
   if (header_parsed_) {
     // Add the data to the content.
-    message_->AppendContent(data, len);
+    AppendContent(data, len);
 
-    if (message_->IsContentFull()) {
+    if (IsContentFull()) {
       // All content has been read.
-      finished_ = true;
+      Finish();
     }
 
     return kNoError;
@@ -66,22 +67,21 @@ Error HttpParser::Parse(const char* data, std::size_t len) {
     // Headers just ended.
 
     if (!content_length_parsed_) {
-      // No Content-Length, no content.
-      message_->SetContentLength(0);
-      finished_ = true;
+      // No Content-Length, no content. (TODO: Support chucked data)
+      Finish();
       return kNoError;
     } else {
       // Invalid Content-Length in the request. 
-      if (!message_->IsContentLengthValid()) {
+      if (content_length_ == kInvalidLength) {
         return kHttpContentLengthError;
       }
     }
 
-    message_->AppendContent(pending_data_.substr(off));
+    AppendContent(pending_data_.substr(off));
 
-    if (message_->IsContentFull()) {
+    if (IsContentFull()) {
       // All content has been read.
-      finished_ = true;
+      Finish();
     }
   } else {
     // Save the unparsed piece for next parsing.
@@ -110,11 +110,28 @@ void HttpParser::ParseContentLength(const std::string& line) {
     std::string value = line.substr(pos);
 
     try {
-      std::size_t length = boost::lexical_cast<std::size_t>(value);
-      message_->SetContentLength(length);
+      content_length_ = boost::lexical_cast<std::size_t>(value);
     } catch (boost::bad_lexical_cast&) {
     }
   }
 }
 
+void HttpParser::Finish() {
+  message_->SetContent(content_);
+  finished_ = true;
+}
+
+void HttpParser::AppendContent(const char* data, std::size_t count) {
+  content_.append(data, count);
+}
+
+void HttpParser::AppendContent(const std::string& data) {
+  content_.append(data);
+}
+
+bool HttpParser::IsContentFull() const {
+  return content_length_ != kInvalidLength &&
+         content_length_ <= content_.length();
+}
+
 }  // namespace webcc
diff --git a/src/webcc/http_parser.h b/src/webcc/http_parser.h
index 9a846c2..b70bc97 100644
--- a/src/webcc/http_parser.h
+++ b/src/webcc/http_parser.h
@@ -13,6 +13,10 @@ class HttpParser {
 public:
   explicit HttpParser(HttpMessage* message);
 
+  ~HttpParser() = default;
+  HttpParser(const HttpParser&) = delete;
+  HttpParser& operator=(const HttpParser&) = delete;
+
   bool finished() const {
     return finished_;
   }
@@ -25,6 +29,13 @@ protected:
 
   void ParseContentLength(const std::string& line);
 
+  void Finish();
+
+  void AppendContent(const char* data, std::size_t count);
+  void AppendContent(const std::string& data);
+
+  bool IsContentFull() const;
+
 protected:
   // The result HTTP message.
   HttpMessage* message_;
@@ -34,7 +45,9 @@ protected:
   // Data waiting to be parsed.
   std::string pending_data_;
 
-  // Parsing helper flags.
+  // Temporary data and helper flags for parsing.
+  std::size_t content_length_;
+  std::string content_;
   bool start_line_parsed_;
   bool content_length_parsed_;
   bool header_parsed_;
diff --git a/src/webcc/http_response.cc b/src/webcc/http_response.cc
index 3b33b52..71fd311 100644
--- a/src/webcc/http_response.cc
+++ b/src/webcc/http_response.cc
@@ -96,7 +96,7 @@ std::vector<boost::asio::const_buffer> HttpResponse::ToBuffers() const {
   buffers.push_back(boost::asio::buffer(misc_strings::CRLF));
 
   // Content (optional)
-  if (IsContentLengthValid()) {
+  if (!content_.empty()) {
     buffers.push_back(boost::asio::buffer(content_));
   }
 
diff --git a/src/webcc/http_session.cc b/src/webcc/http_session.cc
index 7756d8e..7be746c 100644
--- a/src/webcc/http_session.cc
+++ b/src/webcc/http_session.cc
@@ -35,8 +35,7 @@ void HttpSession::SetResponseContent(const std::string& content_type,
                                      std::size_t content_length,
                                      std::string&& content) {
   response_.SetContentType(content_type);
-  response_.SetContentLength(content.length());
-  response_.set_content(std::move(content));
+  response_.SetContent(std::move(content));
 }
 
 void HttpSession::SendResponse() {
diff --git a/src/webcc/soap_client.cc b/src/webcc/soap_client.cc
index ee51def..6f45f6a 100644
--- a/src/webcc/soap_client.cc
+++ b/src/webcc/soap_client.cc
@@ -40,11 +40,9 @@ Error SoapClient::Call(const std::string& operation,
   http_request.set_method(kHttpPost);
   http_request.set_url(url_);
   http_request.SetContentType(kTextXmlUtf8);
-  http_request.SetContentLength(http_content.size());
+  http_request.SetContent(std::move(http_content));
   http_request.SetHost(host_, port_);
   http_request.SetHeader(kSoapAction, operation);
-  http_request.set_content(std::move(http_content));
-
   http_request.Build();
 
   HttpResponse http_response;