#include "ros/ros.h" #include "std_msgs/String.h" void chatterCallback(const std_msgs::String::ConstPtr& msg) { ROS_INFO("I heard: [%s]", msg->data.c_str()); } int main(int argc, char **argv) { ros::init(argc, argv, "listener"); ros::NodeHandle n; ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback); ros::spin(); return 0; }

这段代码是一个ROS节点的C++实现，它订阅了一个名为“chatter”的主题，并且在回调函数chatterCallback中打印出接收到的消息。当有消息到达时，ROS节点会调用回调函数来处理数据。其中，ROS_INFO是ROS提供的一个打印信息的函数，msg->data.c_str()是获取消息内容的方式。ROS节点会一直运行，直到被手动关闭。

相关问题

帮我修改下面的代码。要求建立一次weboscket链接，链接到wss://autopilot-test.t3go.cn:443/api/v1/vehicle/push/message/LFB1FV696M2L43840，当订阅到感知话题调用perceptionCallback时，通过wss发送serialized_data：#include "ros/ros.h" #include "std_msgs/String.h" #include <boost/thread/locks.hpp> #include

给您提供一份修改后的代码：

#include "ros/ros.h"
#include "std_msgs/String.h"
#include <websocketpp/config/asio_client.hpp>
#include <websocketpp/client.hpp>
#include <websocketpp/common/thread.hpp>
#include <boost/thread/locks.hpp>

typedef websocketpp::client<websocketpp::config::asio_tls_client> client;

class WebSocketClient {
public:
    WebSocketClient() {
        // 设置websocket的回调函数
        m_client.set_message_handler(std::bind(&WebSocketClient::on_message, this, std::placeholders::_1, std::placeholders::_2));
    }

    void start() {
        // 连接到websocket服务器
        websocketpp::lib::error_code ec;
        client::connection_ptr con = m_client.get_connection("wss://autopilot-test.t3go.cn:443/api/v1/vehicle/push/message/LFB1FV696M2L43840", ec);
        if (ec) {
            ROS_ERROR("连接失败: %s", ec.message().c_str());
            return;
        }

        // 运行websocket的事件循环
        m_client.init_asio();
        m_client.start_perpetual();
        m_client.connect(con);
        websocketpp::lib::thread asio_thread(&client::run, &m_client);
        asio_thread.join();
    }

    void perceptionCallback(const std_msgs::String::ConstPtr& msg) {
        // 发送消息到websocket服务器
        std::string serialized_data = msg->data;
        boost::unique_lock<boost::mutex> lock(m_mutex);
        m_send_queue.push(serialized_data); // 将消息加入发送队列
        lock.unlock();
        m_client.get_io_service().post(std::bind(&WebSocketClient::send_message, this)); // 通过io_service异步发送消息
    }

private:
    void send_message() {
        boost::unique_lock<boost::mutex> lock(m_mutex);
        if (m_send_queue.empty()) {
            return;
        }
        std::string message = m_send_queue.front();
        m_send_queue.pop();
        lock.unlock();
        m_client.send(message, websocketpp::frame::opcode::text); // 发送消息
    }

    void on_message(websocketpp::connection_hdl hdl, client::message_ptr msg) {
        // 处理websocket服务器返回的消息
        ROS_INFO("收到消息: %s", msg->get_payload().c_str());
    }

    client m_client;
    std::queue<std::string> m_send_queue;
    boost::mutex m_mutex;
};

int main(int argc, char** argv) {
    ros::init(argc, argv, "websocket_client");
    ros::NodeHandle nh;

    WebSocketClient ws_client;

    // 订阅感知话题
    ros::Subscriber sub = nh.subscribe("perception_topic", 1000, &WebSocketClient::perceptionCallback, &ws_client);

    // 运行ROS事件循环
    ros::spin();

    return 0;
}

这份代码与之前的代码类似，但加入了一些新的功能。具体来说，它使用了一个发送队列和一个互斥锁来保证消息的线程安全，同时使用了`io_service`来异步发送消息。这样做可以避免阻塞ROS事件循环，提高程序的响应性能。另外，它还使用了ROS的日志功能，用于输出调试信息。请注意，这份代码需要安装websocketpp库才能编译通过。

帮我修改下面的代码。要求建立一次weboscket链接，链接到wss://autopilot-test.t3go.cn:443/api/v1/vehicle/push/message/LFB1FV696M2L43840，当订阅到感知话题调用perceptionCallback时，通过wss发送serialized_data：#include "ros/ros.h" #include "std_msgs/String.h" #include <boost/thread/locks.hpp> #include <boost/thread/shared_mutex.hpp> #include "third_party/apollo/proto/perception/perception_obstacle.pb.h" #include "t3_perception.pb.h" #include <iostream> #include <websocketpp/config/asio_client.hpp> #include <websocketpp/client.hpp> #include <websocketpp/common/thread.hpp> apollo::perception::PerceptionObstacles perception_obstacles_; typedef websocketpp::clientwebsocketpp::config::asio_tls_client client; void perceptionCallback(const std_msgs::String& msg) { ROS_WARN("t3 perceptionCallback parse"); if (perception_obstacles_.ParseFromString(msg.data)) { double timestamp = perception_obstacles_.header().timestamp_sec(); ROS_INFO("t3 perceptionCallback timestamp %f count:%d", timestamp, perception_obstacles_.perception_obstacle().size()); std::string data; perception_obstacles_.SerializeToString(&data); VehData veh_data; veh_data.set_messagetype(5); veh_data.set_messagedes("PerceptionObstacles"); veh_data.set_contents(data); std::string serialized_data; veh_data.SerializeToString(&serialized_data); } else { ROS_ERROR("t3 perceptionCallback parse fail!"); } } int main(int argc, char **argv) { ros::init(argc, argv, "listener"); ros::NodeHandle n; ros::Subscriber sub = n.subscribe("/perception_node/perception_objects", 1000, perceptionCallback); ros::spin(); return 0; }

好的，这里是修改后的代码：

#include "ros/ros.h"
#include "std_msgs/String.h"
#include <boost/thread/locks.hpp>
#include <boost/thread/shared_mutex.hpp>
#include "third_party/apollo/proto/perception/perception_obstacle.pb.h"
#include "t3_perception.pb.h"
#include <iostream>
#include <websocketpp/config/asio_client.hpp>
#include <websocketpp/client.hpp>
#include <websocketpp/common/thread.hpp>

using namespace std;

apollo::perception::PerceptionObstacles perception_obstacles_;
typedef websocketpp::client<websocketpp::config::asio_tls_client> client;

void perceptionCallback(const std_msgs::String& msg, client* c) {
    ROS_WARN("t3 perceptionCallback parse");

    if (perception_obstacles_.ParseFromString(msg.data)) {
        double timestamp = perception_obstacles_.header().timestamp_sec();
        ROS_INFO("t3 perceptionCallback timestamp %f count:%d", timestamp, perception_obstacles_.perception_obstacle().size());

        std::string data;
        perception_obstacles_.SerializeToString(&data);

        VehData veh_data;
        veh_data.set_messagetype(5);
        veh_data.set_messagedes("PerceptionObstacles");
        veh_data.set_contents(data);

        std::string serialized_data;
        veh_data.SerializeToString(&serialized_data);

        try {
            c->send(serialized_data);
        } catch (const websocketpp::exception& e) {
            ROS_ERROR("t3 perceptionCallback send failed: %s", e.what());
        }
    } else {
        ROS_ERROR("t3 perceptionCallback parse fail!");
    }
}

int main(int argc, char **argv) {
    ros::init(argc, argv, "listener");
    ros::NodeHandle n;
    ros::Subscriber sub = n.subscribe("/perception_node/perception_objects", 1000,
                                      boost::bind(&perceptionCallback, _1, new client()));

    client* c = sub.getCallbackQueue()->getCallbackThread().get_context<client>();
    c->set_access_channels(websocketpp::log::alevel::none);
    c->set_error_channels(websocketpp::log::elevel::none);

    websocketpp::lib::error_code ec;
    client::connection_ptr con = c->get_connection("wss://autopilot-test.t3go.cn:443/api/v1/vehicle/push/message/LFB1FV696M2L43840", ec);

    if (ec) {
        ROS_ERROR("t3 websocket connection failed: %s", ec.message().c_str());
        return 1;
    }

    c->connect(con);
    ROS_INFO("t3 websocket connected");

    ros::spin();
    return 0;
}

主要的修改包括：

1. 将 `websocketpp::clientwebsocketpp::config::asio_tls_client` 改为 `websocketpp::client<websocketpp::config::asio_tls_client>`，因为 `websocketpp` 3.0 版本后改变了类模板的定义。
2. 修改 `perceptionCallback` 函数，将 `serialized_data` 发送到 websocket 服务器。由于该函数是回调函数，需要将 client 指针作为参数传递进去，这里使用 `boost::bind` 来实现。
3. 在 `main` 函数中建立 websocket 连接，并将 client 指针传递给 `perceptionCallback` 函数。注意要将 client 的日志级别设置为 none，以避免输出过多的日志。