https_client.cpp

#include <iostream>
#include <istream>
#include <ostream>
#include <string>
#include <boost/asio.hpp>
#include <boost/bind/bind.hpp>
#include <boost/asio/ssl.hpp>
#include <boost/url/src.hpp>

using boost::asio::ip::tcp;
using std::placeholders::_1;
using std::placeholders::_2;

class client
{
public:
    client(boost::asio::io_service& io_service,
           boost::asio::ssl::context& ssl_context,
           boost::urls::url const &url)
        : resolver_(io_service),
          socket_(io_service, ssl_context)
    {

        const std::string server = url.host();
        const std::string path = url.path();
        const std::string scheme = url.scheme();
        // Form the request. We specify the "Connection: close" header so that the
        // server will close the socket after transmitting the response. This will
        // allow us to treat all data up until the EOF as the content.
        std::ostream request_stream(&request_);
        request_stream << "GET " << path << " HTTP/1.0\r\n";
        request_stream << "Host: " << server << "\r\n";
        request_stream << "Accept: */*\r\n";
        request_stream << "Connection: close\r\n\r\n";

        // Start an asynchronous resolve to translate the server and service names
        // into a list of endpoints.
        std::cout << "client: resolving " << server << " (scheme " << scheme << ") ...\n";
        // Always use https for resolving. If the server really is on http only,
        // the resolver will manage it anyways.
        // If your system doesn't define service https (in /etc/services)
        // simply use the port number 443 here.
        tcp::resolver::query query(server, "https");
        resolver_.async_resolve(query,
                                boost::bind(&client::handle_resolve, this,
                                            boost::asio::placeholders::error,
                                            boost::asio::placeholders::iterator));
    }

private:

    void handle_resolve(const boost::system::error_code& err,
                        tcp::resolver::iterator endpoint_iterator)
    {
        if (!err)
        {
            std::cout << "Resolve OK" << "\n";
            socket_.set_verify_mode(boost::asio::ssl::verify_peer);
            socket_.set_verify_callback(
                        boost::bind(&client::verify_certificate, this, _1, _2));

            boost::asio::async_connect(socket_.lowest_layer(), endpoint_iterator,
                                       boost::bind(&client::handle_connect, this,
                                                   boost::asio::placeholders::error));
        }
        else
        {
            std::cout << "Error resolve: " << err.message() << "\n";
        }
    }

    bool verify_certificate(bool preverified,
                            boost::asio::ssl::verify_context& ctx)
    {
        std::cout << "verify_certificate (preverified " << preverified << " ) ...\n";
        // The verify callback can be used to check whether the certificate that is
        // being presented is valid for the peer. For example, RFC 2818 describes
        // the steps involved in doing this for HTTPS. Consult the OpenSSL
        // documentation for more details. Note that the callback is called once
        // for each certificate in the certificate chain, starting from the root
        // certificate authority.

        // In this example we will simply print the certificate's subject name.
        char subject_name[256];
        X509* cert = X509_STORE_CTX_get_current_cert(ctx.native_handle());
        X509_NAME_oneline(X509_get_subject_name(cert), subject_name, 256);
        std::cout << "Verifying " << subject_name << "\n";

        // dummy verification
        return true;
    }

    void handle_connect(const boost::system::error_code& err)
    {
      std::cout << "handle_connect\n";
        if (!err)
        {
            std::cout << "Connect OK " << "\n";
            socket_.async_handshake(boost::asio::ssl::stream_base::client,
                                    boost::bind(&client::handle_handshake, this,
                                                boost::asio::placeholders::error));
        }
        else
        {
            std::cout << "Connect failed: " << err.message() << "\n";
        }
    }

    void handle_handshake(const boost::system::error_code& error)
    {
        std::cout << "handle_handshake start \n";
        if (!error)
        {
            std::cout << "Handshake OK " << "\n";
            std::cout << "Request: " << "\n";
            const char* header=boost::asio::buffer_cast<const char*>(request_.data());
            std::cout << header << "\n";

            // The handshake was successful. Send the request.
            boost::asio::async_write(socket_, request_,
                                     boost::bind(&client::handle_write_request, this,
                                                 boost::asio::placeholders::error));
        }
        else
        {
            std::cout << "Handshake failed: " << error.message() << "\n";
        }
    }

    void handle_write_request(const boost::system::error_code& err)
    {
        std::cout << "handle_write_request start \n";
        if (!err)
        {
            // Read the response status line. The response_ streambuf will
            // automatically grow to accommodate the entire line. The growth may be
            // limited by passing a maximum size to the streambuf constructor.
            boost::asio::async_read_until(socket_, response_, "\r\n",
                                          boost::bind(&client::handle_read_status_line, this,
                                                      boost::asio::placeholders::error));
        }
        else
        {
            std::cout << "Error write req: " << err.message() << "\n";
        }
    }

    void handle_read_status_line(const boost::system::error_code& err)
    {
        std::cout << "handle_read_status_line start \n";
        if (!err)
        {
            // Check that response is OK.
            std::istream response_stream(&response_);
            std::string http_version;
            response_stream >> http_version;
            unsigned int status_code;
            response_stream >> status_code;
            std::string status_message;
            std::getline(response_stream, status_message);
            if (!response_stream || http_version.substr(0, 5) != "HTTP/")
            {
                std::cout << "Invalid response\n";
                return;
            }
            if (status_code != 200)
            {
                std::cout << "Response returned with status code ";
                std::cout << status_code << "\n";
                return;
            }
            std::cout << "Status code: " << status_code << "\n";

            // Read the response headers, which are terminated by a blank line.
            boost::asio::async_read_until(socket_, response_, "\r\n\r\n",
                                          boost::bind(&client::handle_read_headers, this,
                                                      boost::asio::placeholders::error));
        }
        else
        {
            std::cout << "Error: " << err.message() << "\n";
        }
    }

    void handle_read_headers(const boost::system::error_code& err)
    {
        std::cout << "handle_read_headers\n";
        if (!err)
        {
            // Process the response headers.
            std::istream response_stream(&response_);
            std::string header;
            while (std::getline(response_stream, header) && header != "\r")
                std::cout << header << "\n";
            std::cout << "\n";

            // Write whatever content we already have to output.
            if (response_.size() > 0)
                std::cout << &response_;

            // Start reading remaining data until EOF.
            boost::asio::async_read(socket_, response_,
                                    boost::asio::transfer_at_least(1),
                                    boost::bind(&client::handle_read_content, this,
                                                boost::asio::placeholders::error));
        }
        else
        {
            std::cout << "Error: " << err << "\n";
        }
    }

    void handle_read_content(const boost::system::error_code& err)
    {
        std::cout << "handle_read_content\n";
        if (!err)
        {
            // Write all of the data that has been read so far.
            std::cout << &response_;

            // Continue reading remaining data until EOF.
            boost::asio::async_read(socket_, response_,
                                    boost::asio::transfer_at_least(1),
                                    boost::bind(&client::handle_read_content, this,
                                                boost::asio::placeholders::error));
        }
        else if (err != boost::asio::error::eof)
        {
            std::cout << "Error: " << err << "\n";
        }
    }

    tcp::resolver resolver_;
    boost::asio::ssl::stream<boost::asio::ip::tcp::socket> socket_;
    boost::asio::streambuf request_;
    boost::asio::streambuf response_;
};

int main(int argc, char* argv[])
{
  try
  {
    if (argc != 2)
    {
      std::cout << "Usage: https_client <url>\n";
      std::cout << "Example:\n";
      std::cout << "        https_client https://www.boost.org/LICENSE_1_0.txt\n";
      std::cout << "or\n";
      std::cout << "        https_client http://info.cern.ch/index.html\n";
      std::cout << "        (Yes, this really is still http.)\n";
      return 1;
    }
    // Parse an URL. This allocates no memory. The view
    // references the character buffer without taking ownership.
    boost::urls::url_view uv( argv[1] );
    // Create a modifiable copy of `uv`, with ownership of the buffer
    boost::urls::url url = uv;

    boost::asio::io_context io_context;

    // Create a SSL context that uses the default paths for finding CA certificates:
    boost::asio::ssl::context ssl_context(boost::asio::ssl::context::sslv23);
    ssl_context.set_default_verify_paths();

    client c(io_context, ssl_context, url);
    io_context.run();
  }
  catch (std::exception& e)
  {
    std::cout << "Exception: " << e.what() << "\n";
  }

  return 0;
}