Trait actix::fut::ActorFuture[−][src]

pub trait ActorFuture {
    type Output;
    type Actor: Actor;
    fn poll(
        self: Pin<&mut Self>, 
        srv: &mut Self::Actor, 
        ctx: &mut <Self::Actor as Actor>::Context, 
        task: &mut Context<'_>
    ) -> Poll<Self::Output>;

    fn map<F, U>(self, f: F) -> Map<Self, F>
    where
        F: FnOnce(Self::Output, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> U,
        Self: Sized,
    { ... }

    fn then<F, B>(self, f: F) -> Then<Self, B, F>
    where
        F: FnOnce(Self::Output, &mut Self::Actor, &mut <Self::Actor as Actor>::Context) -> B,
        B: IntoActorFuture<Actor = Self::Actor>,
        Self: Sized,
    { ... }

    fn timeout(self, timeout: Duration) -> Timeout<Self>
    where
        Self: Sized,
    { ... }
}
Expand description

Trait for types which are a placeholder of a value that may become available at some later point in time.

ActorFuture is very similar to a regular Future, only with subsequent combinator closures accepting the actor and its context, in addition to the result.

ActorFuture allows for use cases where future processing requires access to the actor or its context.

Here is an example of a handler on a single actor, deferring work to another actor, and then updating the initiating actor’s state:

use actix::prelude::*;

// The response type returned by the actor future
type OriginalActorResponse = ();
// The error type returned by the actor future
type MessageError = ();
// This is the needed result for the DeferredWork message
// It's a result that combine both Response and Error from the future response.
type DeferredWorkResult = Result<OriginalActorResponse, MessageError>;

impl Handler<DeferredWork> for OriginalActor {
    // Notice the `Response` is an `ActorFuture`-ized version of `Self::Message::Result`.
    type Result = ResponseActFuture<Self, Result<OriginalActorResponse, MessageError>>;

    fn handle(&mut self, _msg: DeferredWork, _ctx: &mut Context<Self>) -> Self::Result {
        // this creates a `Future` representing the `.send` and subsequent `Result` from
        // `other_actor`
        let send_to_other = self.other_actor
            .send(OtherMessage {});

        // Wrap that `Future` so subsequent chained handlers can access
        // the `actor` (`self` in the  synchronous code) as well as the context.
        let send_to_other = actix::fut::wrap_future::<_, Self>(send_to_other);

        // once the wrapped future resolves, update this actor's state
        let update_self = send_to_other.map(|result, actor, _ctx| {
            // Actor's state updated here
            match result {
                Ok(v) => {
                    actor.inner_state.update_from(v);
                    Ok(())
                },
                // Failed to send message to other_actor
                Err(_e) => Err(()),
            }
        });

        // return the wrapped future
        Box::pin(update_self)
    }
}

See also into_actor, which provides future conversion using trait

Associated Types

The type of value that this future will resolved with if it is successful.

The actor within which this future runs

Required methods

Provided methods

Map this future’s result to a different type, returning a new future of the resulting type.

Chain on a computation for when a future finished, passing the result of the future to the provided closure f.

Add timeout to futures chain.

err value get returned as a timeout error.

Implementations on Foreign Types

Implementors