esp-protocols/components/asio/examples/tcp_echo_server/main/echo_server.cpp

/*
 * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Unlicense OR CC0-1.0
 */
#include "asio.hpp"
#include <string>
#include <iostream>
#include "protocol_examples_common.h"
#include "esp_event.h"
#include "nvs_flash.h"

using asio::ip::tcp;

class session
    : public std::enable_shared_from_this<session> {
public:
    session(tcp::socket socket)
        : socket_(std::move(socket))
    {
    }

    void start()
    {
        do_read();
    }

private:
    void do_read()
    {
        auto self(shared_from_this());
        socket_.async_read_some(asio::buffer(data_, max_length),
        [this, self](std::error_code ec, std::size_t length) {
            if (!ec) {
                data_[length] = 0;
                std::cout << data_ << std::endl;
                do_write(length);
            }
        });
    }

    void do_write(std::size_t length)
    {
        auto self(shared_from_this());
        asio::async_write(socket_, asio::buffer(data_, length),
        [this, self](std::error_code ec, std::size_t length) {
            if (!ec) {
                do_read();
            }
        });
    }

    tcp::socket socket_;
    enum { max_length = 1024 };
    char data_[max_length];
};

class server {
public:
    server(asio::io_context &io_context, short port)
        : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
    {
        do_accept();
    }

private:
    void do_accept()
    {
        acceptor_.async_accept(
        [this](std::error_code ec, tcp::socket socket) {
            if (!ec) {
                std::make_shared<session>(std::move(socket))->start();
            }

            do_accept();
        });
    }

    tcp::acceptor acceptor_;
};


extern "C" void app_main(void)
{
    ESP_ERROR_CHECK(nvs_flash_init());
    esp_netif_init();
    ESP_ERROR_CHECK(esp_event_loop_create_default());

    /* This helper function configures Wi-Fi or Ethernet, as selected in menuconfig.
     * Read "Establishing Wi-Fi or Ethernet Connection" section in
     * examples/protocols/README.md for more information about this function.
     */
    ESP_ERROR_CHECK(example_connect());

    /* This helper function configures blocking UART I/O */
    ESP_ERROR_CHECK(example_configure_stdin_stdout());

    asio::io_context io_context;

    server s(io_context, std::atoi(CONFIG_EXAMPLE_PORT));

    std::cout << "ASIO engine is up and running" << std::endl;

    io_context.run();
}