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c++mysqlboost

Boost.MySQL issue with file handle supplication in C++


I'm using Boost.MySQL with boost version 1.84. I want to use the connection so I've created a class and added a connection member variable. I acquire a connection from the MySQL server and save the connection in the class. What happens next is that when I access the connection, I get a file handle error.

The file handle supplied is not valid [system:10009]

The code relevant to the saving of the connection is as follows -


    void initialize(std::string host, int port, std::string user, std::string pass, std::string database)
    {
        try {
            boost::asio::io_context ctx;
            boost::asio::ssl::context ssl_ctx(boost::asio::ssl::context::tls_client);
            _connection = std::make_shared<boost::mysql::tcp_ssl_connection>(ctx.get_executor(), ssl_ctx);
            boost::asio::ip::tcp::resolver resolver(ctx.get_executor());
            auto endpoints = resolver.resolve(host, std::to_string(port));
            boost::mysql::handshake_params params(user, pass, database);
            _connection->connect(*endpoints.begin(), params);
        } catch (boost::mysql::error_with_diagnostics &error) {
            HLog(error) << error.what();
        }

        bool value = _is_initialized;
        _is_initialized.compare_exchange_strong(value, true);
    }

    std::shared_ptr<boost::mysql::tcp_ssl_connection> get_connection() { return _connection; }

The _connection variable is saved in the class and I can later call a small function to test the connection -


    std::shared_ptr<boost::mysql::tcp_ssl_connection> get_database_connection() 
    { 
        return get_component<DatabaseProcess>(DATABASE_MAINFRAME)->get_connection();
    }
    
    bool test_database_connection()
    {
        try {
            const char *sql = "SELECT 'Hello World!'";
            boost::mysql::results result;
            get_database_connection()->execute(sql, result);

            if (result.rows().at(0).at(0).as_string().compare("Hello World!") == 0)
                return true;
        } catch (boost::mysql::error_with_diagnostics &error) {
            HLog(error) << error.what();
        }
        return false;
    }

Solution

  • For reference: the problem is that the tcp_ssl_connection object is being used after the io_context and ssl::context objects go out of scope. They need to be kept alive as long as you're using the connection.