https://twitter.com/myon___/status/646339828083109889

server.cc

#include <iostream>
#include <boost/asio.hpp>

auto main(int argc, char** argv) -> int {
  if (argc != 3) {
    std::cerr << "Usage: " << argv[0] << " <ip> <port>" << std::endl;
    return 1;
  }

  boost::asio::io_service io;

  try {
    const auto ip   = boost::asio::ip::address::from_string(argv[1]);
    const auto port = std::atoi(argv[2]);

    boost::asio::ip::tcp::endpoint endpoint(ip, port);
    boost::asio::ip::tcp::acceptor acceptor(io, endpoint);
    boost::asio::ip::tcp::socket socket(io);

    {
      std::cout << "Server running at http://" << ip.to_string() << ":" << port << "/\n\n";

      acceptor.accept(socket);

      {
        // Read request
        // --------------------------------

        boost::asio::streambuf buf;
        std::istream buf_stream(&buf);

        // request line
        std::string method;
        std::string request_uri;
        std::string http_version;

        boost::asio::read_until(socket, buf, "\r\n");
        buf_stream >> method >> request_uri >> http_version;

        std::cout << "- Request-Line ----------------------\n"
                  << "Method:       " << method       << "\n"
                  << "Request-URI:  " << request_uri  << "\n"
                  << "HTTP-Version: " << http_version << "\n\n";

        // remove \r\n
        buf.consume(2);

        // headers
        boost::asio::read_until(socket, buf, "\r\n\r\n");
        std::cout << "- Request-Header --------------------\n"
                  << &buf;
      }

      {
        // Write response
        // --------------------------------

        const std::string message_body("Hello World!!");

        // status line
        boost::asio::write(socket, boost::asio::buffer("HTTP/1.1 200 Ok\r\n"));

        // headers
        boost::asio::streambuf buf;
        std::ostream buf_stream(&buf);

        buf_stream << "Content-Length: " << message_body.length() << "\r\n"
                   << "Content-Type: text/plain\r\n"
                   << "Connection: close\r\n\r\n";

        boost::asio::write(socket, buf);

        // message body
        boost::asio::write(socket, boost::asio::buffer(message_body));
      }

      socket.close();
    }

    std::cout << std::flush;
  } catch (std::exception& e) {
    std::cerr << "Exception: " << e.what() << std::endl;
  }
}