mrs_lib::ServiceClientHandler< ServiceType > Class Template Reference

user wrapper of the service client handler implementation More...

#include <service_client_handler.h>

Classes
class	Impl
	implementation of the service client handler More...

Public Member Functions
	ServiceClientHandler (rclcpp::Node::SharedPtr &node, const std::string &address, const rclcpp::QoS &qos=rclcpp::ServicesQoS())
	The main constructor with all the options.
	ServiceClientHandler ()
	Default constructor to avoid having to use pointers.
	ServiceClientHandler (rclcpp::Node::SharedPtr &node, const std::string &address, const rclcpp::QoS &qos, const rclcpp::CallbackGroup::SharedPtr &callback_group)
	A convenience constructor.
	ServiceClientHandler (rclcpp::Node::SharedPtr &node, const std::string &address, const rclcpp::CallbackGroup::SharedPtr &callback_group)
	A convenience constructor.
std::optional< std::shared_ptr< typename ServiceType::Response > >	callSync (const std::shared_ptr< typename ServiceType::Request > &request)
	Synchronous (blocking) call of the service.
std::optional< std::shared_future< std::shared_ptr< typename ServiceType::Response > > >	callAsync (const std::shared_ptr< typename ServiceType::Request > &request)
	Asynchronous (non-blocking) call of the service.

Detailed Description

template<class ServiceType>
class mrs_lib::ServiceClientHandler< ServiceType >

user wrapper of the service client handler implementation

Constructor & Destructor Documentation

ServiceClientHandler() [1/4]

template<class ServiceType >

mrs_lib::ServiceClientHandler< ServiceType >::ServiceClientHandler	(	rclcpp::Node::SharedPtr &	node,
		const std::string &	address,
		const rclcpp::QoS &	qos = rclcpp::ServicesQoS()
	)

The main constructor with all the options.

This variant initializes a new MutuallyExclusive callback group for the service client, which is the intended default behavior to avoid deadlocks when using the callSync() method. For a more detailed explanation of the parameters, see the documentation of rclcpp::Node::create_client.

Parameters

node	ROS node handler.
address	Name of the service.
qos	QOS Communication quality of service profile.

ServiceClientHandler() [2/4]

template<class ServiceType >

mrs_lib::ServiceClientHandler< ServiceType >::ServiceClientHandler

(

)

Default constructor to avoid having to use pointers.

It does nothing and the object it constructs will also do nothing. Use some of the other constructors for a construction of an actually usable object.

ServiceClientHandler() [3/4]

template<class ServiceType >

mrs_lib::ServiceClientHandler< ServiceType >::ServiceClientHandler	(	rclcpp::Node::SharedPtr &	node,
		const std::string &	address,
		const rclcpp::QoS &	qos,
		const rclcpp::CallbackGroup::SharedPtr &	callback_group
	)

A convenience constructor.

This is just for convenience when you want to specify the callback group.

Parameters

node	ROS node handler.
address	Name of the service.
qos	QOS Communication quality of service profile.
callback_group	Callback group used internally by the node for the response callback. Set to nullptr to use the default one.

ServiceClientHandler() [4/4]

template<class ServiceType >

mrs_lib::ServiceClientHandler< ServiceType >::ServiceClientHandler	(	rclcpp::Node::SharedPtr &	node,
		const std::string &	address,
		const rclcpp::CallbackGroup::SharedPtr &	callback_group
	)

A convenience constructor.

This is just for convenience when you want to specify the callback group but don't care about QoS.

Parameters

node	ROS node handler.
address	Name of the service.
callback_group	Callback group used internally by the node for the response callback. Set to nullptr to use the default one.

Member Function Documentation

callAsync()

template<class ServiceType >

std::optional< std::shared_future< std::shared_ptr< typename ServiceType::Response > > > mrs_lib::ServiceClientHandler< ServiceType >::callAsync

(

const std::shared_ptr< typename ServiceType::Request > &

request

)

Asynchronous (non-blocking) call of the service.

Parameters

request

The service request to be sent with the call

Returns

Optional shared pointer to the result or std::nullopt if the call failed

callSync()

template<class ServiceType >

std::optional< std::shared_ptr< typename ServiceType::Response > > mrs_lib::ServiceClientHandler< ServiceType >::callSync

(

const std::shared_ptr< typename ServiceType::Request > &

request

)

Synchronous (blocking) call of the service.

This method will block until the service call returns.

Parameters

request

The service request to be sent with the call

Returns

Optional shared pointer to the result or std::nullopt if the call failed

Warning

Take care when using this method! Make sure that the thread and callback group that you're calling it from is not the same as the thread/callback group of the service client or the service server being called! This can typically happen if you call this from another callback or if you're using the SingleThreadedExecutor, and will lead to a deadlock.

---

The documentation for this class was generated from the following files:

• include/mrs_lib/service_client_handler.h
• include/mrs_lib/impl/service_client_handler.hpp