The add_two_ints_client.cpp file in the ros2/demos repository has the following send request function.
Is there a way to make this send request function generic for other services I have created?
Originally posted by mikepark93 on ROS Answers with karma: 47 on 2019-08-05
Post score: 0
Comment by jayess on 2019-08-05:
Please don't use an image to display text/code. Images are not searchable and people cannot copy and paste the text from the image.
Yes, you can use a template.
template<typename ServiceT>
typename ServiceT::Response::SharedPtr send_request(
rclcpp::Node::SharedPtr node,
typename rclcpp::Client<ServiceT>::SharedPtr client,
typename ServiceT::Request::SharedPtr request)
{
auto result = client->async_send_request(request);
// Wait for the result.
if (rclcpp::spin_until_future_complete(node, result) ==
rclcpp::executor::FutureReturnCode::SUCCESS)
{
return result.get();
} else {
return NULL;
}
}
Then you can call it like this
using ServiceT1 = ....
using ServiceT2 = ....
auto node = rclcpp::Node::make_shared("client_node");
auto client_1 = node->create_client<ServiceT1>("my_service_1_name");
auto client_2 = node->create_client<ServiceT2>("my_service_2_name");
auto request_1 = std::make_shared<ServiceT1::Request>();
auto result_1 = send_request<ServiceT1>(node, client_1, request_1);
auto request_2 = std::make_shared<ServiceT2::Request>();
auto result_2 = send_request<ServiceT2>(node, client_2, request_2);
P.S. In ROS2 this is not the recommended style for creating nodes. You should create a class that extends rclcpp::Node and define the send_request function and the clients as members of this class.
Originally posted by alsora with karma: 1322 on 2019-08-05
This answer was ACCEPTED on the original site
Post score: 1
Comment by mikepark93 on 2019-08-05:
When I try building, I get an error saying the following:
error: ‘rclcpp::Client<ServiceT>::SharedPtr’ is not a type rclcpp::Client<ServiceT>::SharedPtr client
Comment by alsora on 2019-08-05:
How have you defined servicet in your code?
Comment by mikepark93 on 2019-08-05:
This was how I defined it before:
rclcpp::Client<orion_sensor::srv::SetFocus>::SharedPtr client
Comment by alsora on 2019-08-05:
So you should use using ServiceT = orion_sensor::srv::SetFocus;.
Or you remove this line and you just keep using orion_sensor::srv::SetFocus as before, changing only the send_request function and adding the template parameter when calling it i.e. send_request<orion_sensor::srv::SetFocus>(...)