【RK3399Pro学习笔记】十一、ROS服务数据的定义与使用

目录

• 自定义服务数据
• • 定义srv文件
  • 在package.xml中添加功能包依赖
  • 在CMakeLists.txt添加编译选项
  • 编译生成语言相关文件
• 使用
• • C++
  • • 编写程序
    • • person_server.cpp
      • person_client.cpp
    • 配置CMakeLists.txt
    • 编译并运行
  • python
  • • 编写程序
    • • person_server.py
      • person_client.py
    • 运行

平台：华硕 Thinker Edge R 瑞芯微 RK3399Pro
固件版本： Tinker_Edge_R-Debian-Stretch-v1.0.13-20210702

---

记录自【古月居】古月·ROS入门21讲 | 一学就会的ROS机器人入门教程 —— 古月居GYH P15 15.服务数据的定义与使用

自定义服务数据 定义srv文件

cd ~/catkin_workspace/src/learning_service
mkdir srv
nano ~/catkin_workspace/src/learning_service/srv/Person.srv

string name
uint8  age
uint8  sex

uint8 unknown = 0
uint8 male    = 1
uint8 female  = 2
---
string result

在package.xml中添加功能包依赖

nano ~/catkin_workspace/src/learning_service/package.xml

message_generation
message_runtime

在CMakeLists.txt添加编译选项

...
find_package(... message_generation)
...
add_service_files(FILES Person.srv)
generate_messages(DEPENDENCIES std_msgs)
...
catkin_package(... message_runtime)
...

nano ~/catkin_workspace/src/learning_service/CMakeLists.txt

编译生成语言相关文件

cd ~/catkin_workspace
catkin_make

结果

cd ~/catkin_workspace/devel/include/learning_service
ls

可见已生成如下文件：

使用 C++ 编写程序 person_server.cpp

nano ~/catkin_workspace/src/learning_service/src/person_server.cpp

 
#include 
#include "learning_service/Person.h"

// service回调函数，输入参数req，输出参数res
bool personCallback(learning_service::Person::Request  &req,
         			learning_service::Person::Response &res)
{
    // 显示请求数据
    ROS_INFO("Person: name:%s  age:%d  sex:%d", req.name.c_str(), req.age, req.sex);

	// 设置反馈数据
	res.result = "OK";

    return true;
}

int main(int argc, char **argv)
{
    // ROS节点初始化
    ros::init(argc, argv, "person_server");

    // 创建节点句柄
    ros::NodeHandle n;

    // 创建一个名为/show_person的server，注册回调函数personCallback
    ros::ServiceServer person_service = n.advertiseService("/show_person", personCallback);

    // 循环等待回调函数
    ROS_INFO("Ready to show person informtion.");
    ros::spin();

    return 0;
}

person_client.cpp

nano ~/catkin_workspace/src/learning_service/src/person_client.cpp

#include 
#include "learning_service/Person.h"

int main(int argc, char** argv)
{
    // 初始化ROS节点
	ros::init(argc, argv, "person_client");

    // 创建节点句柄
	ros::NodeHandle node;

    // 发现/show_person服务后，创建一个服务客户端，连接名为/show_person的service
	ros::service::waitForService("/show_person");
	ros::ServiceClient person_client = node.serviceClient("/show_person");

    // 初始化learning_service::Person的请求数据
	learning_service::Person srv;
	srv.request.name = "Tom";
	srv.request.age  = 20;
	srv.request.sex  = learning_service::Person::Request::male;

    // 请求服务调用
	ROS_INFO("Call service to show person[name:%s, age:%d, sex:%d]", 
			 srv.request.name.c_str(), srv.request.age, srv.request.sex);

	person_client.call(srv);

	// 显示服务调用结果
	ROS_INFO("Show person result : %s", srv.response.result.c_str());

	return 0;
}

配置CMakeLists.txt

nano ~/catkin_workspace/src/learning_service/CMakeLists.txt

添加

add_executable(person_server src/person_server.cpp)
target_link_libraries(person_server ${catkin_LIBRARIES})
add_dependencies(person_server ${PROJECT_NAME}_gencpp)

add_executable(person_client src/person_client.cpp)
target_link_libraries(person_client ${catkin_LIBRARIES})
add_dependencies(person_client ${PROJECT_NAME}_gencpp)

1. 设置需要编译的代码和生成的可执行文件；
2. 设置链接库；
3. 添加依赖项。
   

编译并运行

cd ~/catkin_workspace
catkin_make

# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
roscore
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_service person_server
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_service person_client

python 编写程序 person_server.py

nano ~/catkin_workspace/src/learning_service/scripts/person_server.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

########################################################################
####          Copyright 2020 GuYueHome (www.guyuehome.com).          ###
########################################################################

# 该例程将执行/show_person服务，服务数据类型learning_service::Person

import rospy
from learning_service.srv import Person, PersonResponse

def personCallback(req):
	# 显示请求数据
    rospy.loginfo("Person: name:%s  age:%d  sex:%d", req.name, req.age, req.sex)

	# 反馈数据
    return PersonResponse("OK")

def person_server():
	# ROS节点初始化
    rospy.init_node('person_server')

	# 创建一个名为/show_person的server，注册回调函数personCallback
    s = rospy.Service('/show_person', Person, personCallback)

	# 循环等待回调函数
    print "Ready to show person informtion."
    rospy.spin()

if __name__ == "__main__":
    person_server()

person_client.py

nano ~/catkin_workspace/src/learning_service/scripts/person_client.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

########################################################################
####          Copyright 2020 GuYueHome (www.guyuehome.com).          ###
########################################################################

# 该例程将请求/show_person服务，服务数据类型learning_service::Person

import sys
import rospy
from learning_service.srv import Person, PersonRequest

def person_client():
	# ROS节点初始化
    rospy.init_node('person_client')

	# 发现/spawn服务后，创建一个服务客户端，连接名为/spawn的service
    rospy.wait_for_service('/show_person')
    try:
        person_client = rospy.ServiceProxy('/show_person', Person)

		# 请求服务调用，输入请求数据
        response = person_client("Tom", 20, PersonRequest.male)
        return response.result
    except rospy.ServiceException, e:
        print "Service call failed: %s"%e

if __name__ == "__main__":
	#服务调用并显示调用结果
    print "Show person result : %s" %(person_client())

运行

sudo chmod +x ~/catkin_workspace/src/learning_service/scripts/person_server.py
sudo chmod +x ~/catkin_workspace/src/learning_service/scripts/person_client.py

# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
roscore
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_service person_server.py
# 新建一个终端
source ~/catkin_workspace/devel/setup.bash
rosrun learning_service person_client.py