Trait actix::fut::future::ActorFuture

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

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

type Output

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

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Required methods

fn poll(
    self: Pin<&mut Self>,
    srv: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

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Implementations on Foreign Types

impl<A, B, Act> ActorFuture<Act> for Either<A, B> where
    A: ActorFuture<Act>,
    B: ActorFuture<Act, Output = A::Output>,
    Act: Actor, 

type Output = A::Output

fn poll(
    self: Pin<&mut Self>,
    act: &mut Act,
    ctx: &mut Act::Context,
    task: &mut Context<'_>
) -> Poll<A::Output>

impl<F: ?Sized, A> ActorFuture<A> for Box<F> where
    F: ActorFuture<A> + Unpin,
    A: Actor, 

type Output = F::Output

fn poll(
    self: Pin<&mut Self>,
    srv: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

impl<P, A> ActorFuture<A> for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: ActorFuture<A>,
    A: Actor, 

type Output = <<P as Deref>::Target as ActorFuture<A>>::Output

fn poll(
    self: Pin<&mut Self>,
    srv: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

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Implementors

impl<A> ActorFuture<A> for TimerFunc<A> where
    A: Actor, 

type Output = ()

fn poll(
    self: Pin<&mut Self>,
    act: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

impl<A, B, F, Act> ActorFuture<Act> for Then<A, B, F> where
    A: ActorFuture<Act>,
    B: ActorFuture<Act>,
    F: FnOnce(A::Output, &mut Act, &mut Act::Context) -> B,
    Act: Actor, 

type Output = B::Output

fn poll(
    self: Pin<&mut Self>,
    act: &mut Act,
    ctx: &mut Act::Context,
    task: &mut Context<'_>
) -> Poll<B::Output>

impl<F, A> ActorFuture<A> for FutureWrap<F, A> where
    F: Future,
    A: Actor, 

type Output = F::Output

fn poll(
    self: Pin<&mut Self>,
    _: &mut A,
    _: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

impl<F, A> ActorFuture<A> for Timeout<F> where
    F: ActorFuture<A>,
    A: Actor, 

type Output = Result<F::Output, ()>

fn poll(
    self: Pin<&mut Self>,
    act: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

impl<S, A> ActorFuture<A> for Finish<S> where
    S: ActorStream<A>,
    A: Actor, 

type Output = ()

fn poll(
    self: Pin<&mut Self>,
    act: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<()>

impl<S, A, C> ActorFuture<A> for Collect<S, C> where
    S: ActorStream<A>,
    A: Actor,
    C: Default + Extend<S::Item>, 

type Output = C

fn poll(
    self: Pin<&mut Self>,
    act: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

impl<S, A, F, Fut> ActorFuture<A> for Fold<S, F, Fut, Fut::Output> where
    S: ActorStream<A>,
    A: Actor,
    F: FnMut(Fut::Output, S::Item, &mut A, &mut A::Context) -> Fut,
    Fut: ActorFuture<A>, 

type Output = Fut::Output

fn poll(
    self: Pin<&mut Self>,
    act: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

impl<T, A> ActorFuture<A> for Ready<T> where
    A: Actor, 

type Output = T

fn poll(
    self: Pin<&mut Self>,
    _: &mut A,
    _: &mut A::Context,
    cx: &mut Context<'_>
) -> Poll<Self::Output>

impl<U, Fut, A, F> ActorFuture<A> for Map<Fut, F> where
    Fut: ActorFuture<A>,
    A: Actor,
    F: FnOnce(Fut::Output, &mut A, &mut A::Context) -> U, 

type Output = U

fn poll(
    self: Pin<&mut Self>,
    act: &mut A,
    ctx: &mut A::Context,
    task: &mut Context<'_>
) -> Poll<Self::Output>

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