boost::asio::async_accept the handler is not called

Question

took example from boost https://www.boost.org/doc/libs/1_70_0/doc/html/boost_asio/example/cpp11/ssl/server.cpp

exactly as it is assembled it started it works. then took the implementation from the interface to SSL_Server.h, SSL_Server.cpp, Session.h, Session.cpp, main brought it to Serv.cpp As a result, the handler is not called !!! I do not understand what is the reason.

SSL_Server.h

#ifndef SSL_SERVER
#define SSL_SERVER

#define BOOST_ASIO_ENABLE_HANDLER_TRACKING

#include "Session.h"
#include <functional>
#include <iostream>
#include <boost/asio.hpp>
#include <boost/asio/ssl.hpp>

using boost::asio::ip::tcp;

class SSL_Server
{
public:
SSL_Server(boost::asio::io_context& io_context, unsigned short port);
private:
void do_accept();
std::string get_password() const;
private:
tcp::acceptor acceptor_;
boost::asio::ssl::context context_;
};
#endif

SSL_Server.cpp

#include "Server_SSL.h"

SSL_Server::SSL_Server(boost::asio::io_context& io_context, unsigned short port)
    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port)),
    context_(boost::asio::ssl::context::sslv23)
{
    context_.set_options(
        boost::asio::ssl::context::default_workarounds
        | boost::asio::ssl::context::no_sslv2
        | boost::asio::ssl::context::single_dh_use);
    context_.set_password_callback(std::bind(&SSL_Server::get_password, this));
    context_.use_certificate_chain_file("server.crt");
    context_.use_private_key_file("server.key", boost::asio::ssl::context::pem);
    context_.use_tmp_dh_file("dh2048.pem");

    do_accept();
}


std::string SSL_Server::get_password() const
{
        return "test";
}

void SSL_Server::do_accept()
{
    acceptor_.async_accept([this](const boost::system::error_code& error, tcp::socket socket)
    {
         if (!error)
         {
             std::make_shared<session>(std::move(socket), context_)->start();
         }
    });
}
    

Session.h

#ifndef SESSION
#define SESSION
#include <iostream>
#include <boost/asio.hpp>
#include <boost/asio/ssl.hpp>

using boost::asio::ip::tcp;

class session : public std::enable_shared_from_this<session>
{
public:
    session(tcp::socket socket, boost::asio::ssl::context& context);

    void start();
private:
    void do_handshake();
    void do_read();
    void do_write(std::size_t length);
private:
    boost::asio::ssl::stream<tcp::socket> socket_;
    char data_[1024];
};

#endif
    

Session.cpp

#include "Session.h"
session::session(tcp::socket socket, boost::asio::ssl::context& context)
    : socket_(std::move(socket), context)
{
}

void session::start()
{
    do_handshake();
}

void session::do_handshake()
{
    auto self(shared_from_this());
    socket_.async_handshake(boost::asio::ssl::stream_base::server,
        [this, self](const boost::system::error_code& error)
        {
            if (!error)
            {
                do_read();
            }
        });
}

void session::do_read()
{
    auto self(shared_from_this());
    socket_.async_read_some(boost::asio::buffer(data_),
        [this, self](const boost::system::error_code& ec, std::size_t length)
        {
            if (!ec)
            {
                do_write(length);
            }
        });
}
void session::do_write(std::size_t length)
{
    auto self(shared_from_this());
    boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
        [this, self](const boost::system::error_code& ec,
            std::size_t /*length*/)
        {
            if (!ec)
            {
                do_read();
            }
        });
}
    

Serv.cpp

#include "Server_SSL.h"

int main(int argc, char* argv[])
{
        if (argc != 2)
        {
            std::cerr << "Usage: server <port>\n";
            return 1;
        }

        boost::asio::io_context io_context;
        SSL_Server s(io_context, 3333);
        io_context.run();

    return 0;
}

Answer 1

I see nothing wrong with the code. In fact it works for me. HOWEVER, you need the certificate, key and DH param files present in the working directory.

I don't see a lot of of explicit error handling, so I suppose this is your likely problem:

context_.use_certificate_chain_file("server.crt", ec);
if (ec) throw boost::system::system_error(ec);

context_.use_private_key_file("server.key", boost::asio::ssl::context::pem, ec);
if (ec) throw boost::system::system_error(ec);

context_.use_tmp_dh_file("dh2048.pem", ec);
if (ec) throw boost::system::system_error(ec);

Note

I used the server.pem and dh2048.pem files from the boost examples, so it became

context_.use_certificate_chain_file("server.pem", ec);
if (ec) throw boost::system::system_error(ec);

context_.use_private_key_file("server.pem", boost::asio::ssl::context::pem, ec);
if (ec) throw boost::system::system_error(ec);