Implementing ROS 2 services in C++

In this section, we will implement a ROS 2 service server and client using C++. The service server listens to a service called concat_strings with a custom service type of master_ros2_interface::srv::ConcatStrings. If it gets a request from the service client, the server will concatenate both strings it got and reply to the client.

You can find the server and client code in Chapter03 | master_ros2_pkg | src | simple_server.cpp and simple_client.cpp.

Adding a custom service interface

The first thing to do before writing server and client code is to write a custom service type.

Here is the custom service type we have defined:

string str1
string str2
---
string concatenated_str

We have to save this definition as master_ros2_interface/srv/ConcatStrings.srv. The first two strings are for the request field, and the third is for the reply field. The request and reply are separated by ---.

Editing CMakeLists.txt

After saving...