13客户端Client的编程实现

13客户端Client的编程实现

1、创建功能包
进入工作空间catkin_ws/src下面打开功能包

chen@ubuntu:~/catkin_ws/src$ catkin_create_pkg learning_service roscpp rospy std_msgs geometry_msgs turtlesim
usage: catkin_create_pkg [-h] [--meta] [-s [SYS_DEPS [SYS_DEPS ...]]]
                         [-b [BOOST_COMPS [BOOST_COMPS ...]]] [-V PKG_VERSION]
                         [-D DESCRIPTION] [-l LICENSE] [-a AUTHOR]
                         [-m MAINTAINER] [--rosdistro ROSDISTRO]
                         name [dependencies [dependencies ...]]
catkin_create_pkg: error: File exists: /home/chen/catkin_ws/src/learning_service/package.xml

需要依赖的第三方功能包：roscpp rospy std_msge geometry_msgs turtlesim
2、创建客户端代码C++

把客户端代码放入功能包的src中

/

**
 * 该例程将请求/spawn服务，服务数据类型turtlesim::Spawn
 */

#include 
#include 

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

    // 创建节点句柄
	ros::NodeHandle node;

    // 发现/spawn服务后，创建一个服务客户端，连接名为/spawn的service
	ros::service::waitForService("/spawn");
	ros::ServiceClient add_turtle = node.serviceClient<turtlesim::Spawn>("/spawn");

    // 初始化turtlesim::Spawn的请求数据
	turtlesim::Spawn srv;
	srv.request.x = 2.0;
	srv.request.y = 2.0;
	srv.request.name = "turtle2";

    // 请求服务调用
	ROS_INFO("Call service to spwan turtle[x:%0.6f, y:%0.6f, name:%s]", 
			 srv.request.x, srv.request.y, srv.request.name.c_str());

	add_turtle.call(srv);

	// 显示服务调用结果
	ROS_INFO("Spwan turtle successfully [name:%s]", srv.response.name.c_str());

	return 0;
};

3、配置客户端代码编译规则

add_executable(turtle_spawn src/turtle_spawn.cpp)
target_link_libraries(turtle_spawn ${catkin_LIBRARIES})

4、编译并运行客户端

chen@ubuntu:~/catkin_ws$ catkin_make

在devel中编译生成的可执行文件

5.运行
5.1、运行roscore
5.2运行仿真器显示节点

chen@ubuntu:~$ rosrun turtlesim 
draw_square        mimic              turtlesim_node     turtle_teleop_key
chen@ubuntu:~$ rosrun turtlesim turtlesim_node 
[ INFO] [1582773496.228019937]: Starting turtlesim with node name /turtlesim
[ INFO] [1582773496.232371953]: Spawning turtle [turtle1] at x=[5.544445], y=[5.544445], theta=[0.000000]

5.3 运行客户端节点
按tab键补全，出现两只小海龟

chen@ubuntu:~$ rosrun learning_service turtle_spawn
[ INFO] [1582773599.365576304]: Call service to spwan turtle[x:2.000000, y:2.000000, name:turtle2]
//请求service
[ INFO] [1582773599.385445464]: Spwan turtle successfully [name:turtle2]
//应答

同时仿真器显示客户端界面也会出现海龟2信息

[ INFO] [1582773599.379247073]: Spawning turtle [turtle2] at x=[2.000000], y=[2.000000], theta=[0.000000]

二、14服务端Server的编程实现
1.1创建服务器代码（C++）

查看消息内容chen@ubuntu:~$ rossrv show std_srvs/Trigger

rossrv show std_srvs/Trigger`

1.2配置服务器代码编译规则

1.3编译并运行服务器

查看需不需source ，或者功能包找不到

vi .bashrc

添加下面脚本

配置编译规则
add_executable(turtle_command_server src/turtle_command_server.cpp)
target_link_libraries(turtle_command_server ${catkin_LIBRARIES})
打开服务器终端节点

chen@ubuntu:~$ rosrun learning_service turtle_command_server
[ INFO] [1582776144.242303889]: Ready to receive turtle command.

向server发送请求，让海龟动

chen@ubuntu:~$ rosservice call /turtle_command "{}" 

enter后

chen@ubuntu:~$ rosservice call /turtle_command "{}" 
success: True
message: "Change turtle command state!"

停下来

chen@ubuntu:~$ rosservice call /turtle_command "{}" 
success: True
message: "Change turtle command state!"

三、服务数据的定义与使用
1.1自定义服务数据
通过"—“区分，”—“以上为request ,”—"以下为response.
创建srv文件夹和Person.srv文件，并写入内容

chen@ubuntu:~/catkin_ws/src/learning_service$ mkdir srv/
chen@ubuntu:~/catkin_ws/src/learning_service$ cd srv/
chen@ubuntu:~/catkin_ws/src/learning_service/srv$ touch Person.srv
chen@ubuntu:~/catkin_ws/src/learning_service/srv$ 

内容：

string name
uint8 sex
uint8 age

uint8 unknown=0
uint8 male   =1
uint8 female =2
//以上通过client发给sever
---
string result

1.2在package.xml中添加功能包依赖

通过find_package找到这个文件，作为功能包的一个依赖。

message_generation

下面代码是为了让编译器知道，要根据 Person.srv文件来产生对应的头文件

## Generate added messages and services with any dependencies listed here
# generate_messages(
#   DEPENDENCIES
#   geometry_msgs#   std_msgs
# )

add_service_files(FILES Person.srv)
generate_messages(DEPENDENCIES std_msgs)
################################################
## Declare ROS dynamic reconfigure parameters ##
################################################
```bash

add_message_files(FILES Person.srv)
generate_messages(DEPENDENCIES std_msgs)

```bash
message_generation
message_runtime

1.3 在CMakeList.txt添加编译选项

CATKIN_DEPENDS geometry_msgs roscpp rospy std_msgs turtlesim message_runtime

add_executable(turtle_command_server src/turtle_command_server.cpp)
target_link_libraries(turtle_command_server ${catkin_LIBRARIES})

add_executable(turtle_spawn src/turtle_spawn.cpp)
target_link_libraries(turtle_spawn ${catkin_LIBRARIES})

编译生成的头文件，request和response单独分开，并有一个总的头文件，C++文件

2 创建服务器代码 C++


3、配置服务器/客户端代码编译规则

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

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

再次编译：

chen@ubuntu:~/catkin_ws$ catkin_make

4、运行
4.1、rescore
4.2、运行server端
chen@ubuntu:~$ rosrun learning_service person_server
[ INFO] [1582788002.519354137]: Ready to show person informtion.
4.3、运行client端

chen@ubuntu:~$ rosrun learning_service person_client
[ INFO] [1582788108.790908017]: Call service to show person[name:Tom, age:20, sex:1]
[ INFO] [1582788108.794107997]: Show person result : OK

客户端请求数据，收到后显示ok

server端发送如下 ：

chen@ubuntu:~$ rosrun learning_service person_server
[ INFO] [1582788002.519354137]: Ready to show person informtion.
[ INFO] [1582788108.792867917]: Person: name:Tom  age:20  sex:1