doc/html/boost_asio/example/cpp03/ssl/client.cpp
//
// client.cpp
// ~~~~~~~~~~
//
// Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include <cstdlib>
#include <iostream>
#include <boost/bind/bind.hpp>
#include <boost/asio.hpp>
#include <boost/asio/ssl.hpp>
enum { max_length = 1024 };
class client
{
public:
client(boost::asio::io_context& io_context,
boost::asio::ssl::context& context,
boost::asio::ip::tcp::resolver::results_type endpoints)
: socket_(io_context, context)
{
socket_.set_verify_mode(boost::asio::ssl::verify_peer);
socket_.set_verify_callback(
boost::bind(&client::verify_certificate, this,
boost::placeholders::_1, boost::placeholders::_2));
boost::asio::async_connect(socket_.lowest_layer(), endpoints,
boost::bind(&client::handle_connect, this,
boost::asio::placeholders::error));
}
bool verify_certificate(bool preverified,
boost::asio::ssl::verify_context& ctx)
{
// 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";
return preverified;
}
void handle_connect(const boost::system::error_code& error)
{
if (!error)
{
socket_.async_handshake(boost::asio::ssl::stream_base::client,
boost::bind(&client::handle_handshake, this,
boost::asio::placeholders::error));
}
else
{
std::cout << "Connect failed: " << error.message() << "\n";
}
}
void handle_handshake(const boost::system::error_code& error)
{
if (!error)
{
std::cout << "Enter message: ";
std::cin.getline(request_, max_length);
size_t request_length = strlen(request_);
boost::asio::async_write(socket_,
boost::asio::buffer(request_, request_length),
boost::bind(&client::handle_write, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
std::cout << "Handshake failed: " << error.message() << "\n";
}
}
void handle_write(const boost::system::error_code& error,
size_t bytes_transferred)
{
if (!error)
{
boost::asio::async_read(socket_,
boost::asio::buffer(reply_, bytes_transferred),
boost::bind(&client::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
std::cout << "Write failed: " << error.message() << "\n";
}
}
void handle_read(const boost::system::error_code& error,
size_t bytes_transferred)
{
if (!error)
{
std::cout << "Reply: ";
std::cout.write(reply_, bytes_transferred);
std::cout << "\n";
}
else
{
std::cout << "Read failed: " << error.message() << "\n";
}
}
private:
boost::asio::ssl::stream<boost::asio::ip::tcp::socket> socket_;
char request_[max_length];
char reply_[max_length];
};
int main(int argc, char* argv[])
{
try
{
if (argc != 3)
{
std::cerr << "Usage: client <host> <port>\n";
return 1;
}
boost::asio::io_context io_context;
boost::asio::ip::tcp::resolver resolver(io_context);
boost::asio::ip::tcp::resolver::results_type endpoints =
resolver.resolve(argv[1], argv[2]);
boost::asio::ssl::context ctx(boost::asio::ssl::context::sslv23);
ctx.load_verify_file("ca.pem");
client c(io_context, ctx, endpoints);
io_context.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}