Template Class Client

Nested Relationships

Nested Types

Inheritance Relationships

Base Type

Class Documentation

template<typename ActionT>
class Client : public rclcpp_action::ClientBase

Action Client.

This class creates an action client.

To create an instance of an action client use rclcpp_action::create_client().

Internally, this class is responsible for:

Public Types

using Goal = typename ActionT::Goal
using Feedback = typename ActionT::Feedback
using GoalHandle = ClientGoalHandle<ActionT>
using WrappedResult = typename GoalHandle::WrappedResult
using GoalResponseCallback = std::function<void(typename GoalHandle::SharedPtr)>
using FeedbackCallback = typename GoalHandle::FeedbackCallback
using ResultCallback = typename GoalHandle::ResultCallback
using CancelRequest = typename ActionT::Impl::CancelGoalService::Request
using CancelResponse = typename ActionT::Impl::CancelGoalService::Response
using CancelCallback = std::function<void(typename CancelResponse::SharedPtr)>

Public Functions

inline Client(rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base, rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph, rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging, const std::string &action_name, const rcl_action_client_options_t &client_options = rcl_action_client_get_default_options())

Construct an action client.

This constructs an action client, but it will not work until it has been added to a node. Use rclcpp_action::create_client() to both construct and add to a node.

Parameters:

  • node_base – [in] A pointer to the base interface of a node.

  • node_graph – [in] A pointer to an interface that allows getting graph information about a node.

  • node_logging – [in] A pointer to an interface that allows getting a node’s logger.

  • action_name – [in] The action name.

  • client_options – [in] Options to pass to the underlying rcl_action::rcl_action_client_t.

inline std::shared_future<typename GoalHandle::SharedPtr> async_send_goal(const Goal &goal, const SendGoalOptions &options = SendGoalOptions())

Send an action goal and asynchronously get the result.

If the goal is accepted by an action server, the returned future is set to a ClientGoalHandle. If the goal is rejected by an action server, then the future is set to a nullptr.

The returned goal handle is used to monitor the status of the goal and get the final result. It is valid as long as you hold a reference to the shared pointer or until the rclcpp_action::Client is destroyed at which point the goal status will become UNKNOWN.

Parameters:

  • goal – [in] The goal request.

  • options – [in] Options for sending the goal request. Contains references to callbacks for the goal response (accepted/rejected), feedback, and the final result.

Returns:

A future that completes when the goal has been accepted or rejected. If the goal is rejected, then the result will be a nullptr.

inline std::shared_future<WrappedResult> async_get_result(typename GoalHandle::SharedPtr goal_handle, ResultCallback result_callback = nullptr)

Asynchronously get the result for an active goal.

Throws:

exceptions::UnknownGoalHandleError – If the goal unknown or already reached a terminal state, or if there was an error requesting the result.

Parameters:

  • goal_handle – [in] The goal handle for which to get the result.

  • result_callback – [in] Optional callback that is called when the result is received.

Returns:

A future that is set to the goal result when the goal is finished.

inline std::shared_future<typename CancelResponse::SharedPtr> async_cancel_goal(typename GoalHandle::SharedPtr goal_handle, CancelCallback cancel_callback = nullptr)

Asynchronously request a goal be canceled.

Throws:

exceptions::UnknownGoalHandleError – If the goal is unknown or already reached a terminal state.

Parameters:

  • goal_handle – [in] The goal handle requesting to be canceled.

  • cancel_callback – [in] Optional callback that is called when the response is received. The callback takes one parameter: a shared pointer to the CancelResponse message.

Returns:

A future to a CancelResponse message that is set when the request has been acknowledged by an action server. See action_msgs/CancelGoal.srv.

inline std::shared_future<typename CancelResponse::SharedPtr> async_cancel_all_goals(CancelCallback cancel_callback = nullptr)

Asynchronously request for all goals to be canceled.

Parameters:

cancel_callback – [in] Optional callback that is called when the response is received. The callback takes one parameter: a shared pointer to the CancelResponse message.

Returns:

A future to a CancelResponse message that is set when the request has been acknowledged by an action server. See action_msgs/CancelGoal.srv.

inline std::shared_future<typename CancelResponse::SharedPtr> async_cancel_goals_before(const rclcpp::Time &stamp, CancelCallback cancel_callback = nullptr)

Asynchronously request all goals at or before a specified time be canceled.

Parameters:

  • stamp – [in] The timestamp for the cancel goal request.

  • cancel_callback – [in] Optional callback that is called when the response is received. The callback takes one parameter: a shared pointer to the CancelResponse message.

Returns:

A future to a CancelResponse message that is set when the request has been acknowledged by an action server. See action_msgs/CancelGoal.srv.

inline virtual ~Client()
struct SendGoalOptions

Options for sending a goal.

This struct is used to pass parameters to the function async_send_goal.

Public Functions

inline SendGoalOptions()

Public Members

GoalResponseCallback goal_response_callback

Function called when the goal is accepted or rejected.

Takes a single argument that is a goal handle shared pointer. If the goal is accepted, then the pointer points to a valid goal handle. If the goal is rejected, then pointer has the value nullptr.

FeedbackCallback feedback_callback

Function called whenever feedback is received for the goal.

ResultCallback result_callback

Function called when the result for the goal is received.