ROS学习笔记8_服务数据的定义与使用-CFANZ编程社区

如上图中的模型，此时希望在之前的服务器客户端的模型中发送人员信息可以通过service的方式，请求之后才去发送，同时在请求中使用自定义的服务数据类型learning_service::Person。

如何自定义服务数据

定义srv文件，在文件中定义服务数据的各个成员数据，在这里是Person.srv;
在package.xml中添加功能包依赖 <build_depend>message_generation</build_depend> <exec_depend>message_runtime</exec_depend>
在CMakeList.txt中添加编译选项
编译生成语言相关文件

Person.srv中---以上是request数据，---以下是response数据

string name
uint8 age
uint8 sex


uint8 unknown = 0
uint8 male = 1
uint8 female = 2

---
string result

在learning_service目录下创建srv文件夹后，添加该文件。

package.xml中添加依赖

CMakeList.txt中添加编译选项

find_package下加message_generaiton

添加service文件，用来说明生成头文件的依赖和产生消息类型所需的依赖

在catkin_package下添加依赖message_runtime

完成后保存编译，在该目录下产生了总体，请求和反馈的三个头文件。

至此service数据已经生成完毕，开始编写Client和Server端。

client端

/*
	this program will ask for service named /show_person, service data type is learning_service::Person
*/

#include<ros/ros.h>
#include"learning_service/Person.h"

int main(int argc, char **argv)
{
	//initiate ros node
	ros::init(argc, argv, "person_client");
	
	//create node handle
	ros::NodeHandle node;
	
	//create a client node after finding the /show_person service, connect the service named /show_person
	ros::service::waitForService("show_person");
	ros::ServiceClient person_client = node.serviceClient<learning_service::Person>("/show_person");
	
	//initiate the request data of learning_service::Person
	learning_service::Person srv;
	srv.request.name = "Tom";
	srv.request.age = 20;
	srv.request.sex = learning_service::Person::Request::male;
	
	//show the called service
	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);
	
	//show the calling result
	ROS_INFO("Show person result : %s", srv.response.result.c_str());
	
	return 0;
}

server端

/*
	this program serves as the server
*/

#include<ros/ros.h>
#include"learning_service/Person.h"

//service callback function, input argument req, output argument res
bool personCallback(learning_service::Person::Request &req, learning_service::Person::Response &res)
{
	//show request data
	ROS_INFO("Person: name:%s  age:%d  sex:%d",req.name.c_str(), req.age, req.sex);
	
	//set the callback data
	res.result = "OK";
	
	return true;
}

int main(int argc, char **argv)
{
	//initiate ros node
	ros::init(argc, argv, "person_server");
	
	//create node handle
	ros::NodeHandle n;
	
	//create a server named /show_person, register the callback function
	ros::ServiceServer person_service = n.advertiseService("/show_person", personCallback);
	
	//waiting for the callback function
	ROS_INFO("Ready to show person information.");
	ros::spin();
	
	return 0;


}

之后在CMakeList.txt文件中，设置需要编译的代码和可执行文件，设置链接库，添加依赖项（动态生成代码匹配）。

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)