void tcp_server_task(void *pvParameters)
{
    ESP_LOGI(TCP_TAG, "task tcp_conn.");

    tcp_server_task_restart = false;

    /*create tcp socket*/
    int socket_ret;

    ESP_LOGI(TCP_TAG, "tcp_server will start after 50ms!");
    vTaskDelay(50 / portTICK_RATE_MS);
    ESP_LOGI(TCP_TAG, "creating tcp server...");
    socket_ret = create_tcp_server();

    if (socket_ret == ESP_FAIL)
    {
        ESP_LOGI(TCP_TAG, "create tcp socket error,stop.");
        FlowMeterData.TCP_conn = false;
        tcp_server_task_restart = true;
        vTaskDelete(NULL);
    }

    /*create a task to tx/rx data*/
    //TaskHandle_t tx_rx_task;
    //xTaskCreate(&send_data, "send_data", 4096, NULL, 4, &tx_rx_task);
    //xTaskCreate(&recv_data, "recv_data", 4096, NULL, 4, &tx_rx_task);
    while (!tcp_server_task_restart)
    {
        uint8_t databuff[EXAMPLE_DEFAULT_PKTSIZE];
        int len = recv(connect_socket, databuff, EXAMPLE_DEFAULT_PKTSIZE, 0);
        FlowMeterData.TCP_len = len;
        if (len > 0)
        {
            memcpy(FlowMeterData.TCP_Buf, databuff, FlowMeterData.TCP_len);
            printf("TCP(FLAG==1): FL_len:%d, FL_data:%s\n", FlowMeterData.TCP_len, FlowMeterData.TCP_Buf); // debug
            FlowMeterData.TCP_got_packet = true;
            infoLED_WIFI_toggle();
        }

        vTaskDelay(10 / portTICK_RATE_MS); //every 10ms

        if (len <= 0)
        {
            int err_ret = check_working_socket();
            if (err_ret == ECONNRESET || ECONNABORTED)
            {
                ESP_LOGW(TCP_TAG, "tcp disconnected... stop.\n");
                printf("Code:%d\n", err_ret);
                if (err_ret == ENOTCONN)
                {
                    ESP_LOGW(TCP_TAG, "(Socket is not connected)\n");
                }
                break;
            }
        }
    }
    close_socket();
    printf("socket closed\n");
    FlowMeterData.TCP_conn = false;
    set_wifi_exchange_stopped();
    tcp_server_task_restart = true;
    vTaskDelete(NULL);
}