Struct Client

pub struct Client<T>
where
    T: Service,
{ /* private fields */ }

Main class responsible for sending requests to a ROS service.

The only available way to instantiate clients is via Node::create_client, this is to ensure that Nodes can track all the clients that have been created.

Implementations

impl<T> Client<T>

where T: Service,

pub fn async_send_request_with_callback<'a, M: MessageCow<'a, T::Request>, F>( &self, message: M, callback: F, ) -> Result<(), RclrsError>

where F: FnOnce(T::Response) + 'static + Send,

Sends a request with a callback to be called with the response.

The MessageCow trait is implemented by any Message as well as any reference to a Message.

The reason for allowing owned messages is that publishing owned messages can be more efficient in the case of idiomatic messages¹.

Hence, when a message will not be needed anymore after publishing, pass it by value. When a message will be needed again after publishing, pass it by reference, instead of cloning and passing by value.

---

1. See the Message trait for an explanation of “idiomatic”. ↩

pub async fn call_async<'a, R: MessageCow<'a, T::Request>>( &self, request: R, ) -> Result<T::Response, RclrsError>

where T: Service,

Sends a request and returns the response as a Future.

The MessageCow trait is implemented by any Message as well as any reference to a Message.

The reason for allowing owned messages is that publishing owned messages can be more efficient in the case of idiomatic messages¹.

Hence, when a message will not be needed anymore after publishing, pass it by value. When a message will be needed again after publishing, pass it by reference, instead of cloning and passing by value.

---

1. See the Message trait for an explanation of “idiomatic”. ↩

pub fn take_response( &self, ) -> Result<(T::Response, rmw_request_id_t), RclrsError>

Fetches a new response.

When there is no new message, this will return a ClientTakeFailed.

pub fn service_is_ready(&self) -> Result<bool, RclrsError>

Check if a service server is available.

Will return true if there is a service server available, false if unavailable.

Trait Implementations

impl<T> ClientBase for Client<T>

where T: Service,

fn handle(&self) -> &ClientHandle

Internal function to get a reference to the rcl handle.

fn execute(&self) -> Result<(), RclrsError>

Tries to take a new response and run the callback or future with it.