toml
flo_stream = "0.1"
flo_stream
is a crate providing some extra utilities for streams in Rust's futures
library. The primary new feature
it provides is a "pubsub" mechanism - a way to subscribe to updates sent to a futures Sink
. This differs from the
Sender
/Receiver
mechanism provided in the main futures library in two key ways: it's possible to have multiple
receivers, and messages sent when there is no subscriber connected will be ignored.
The sink type provided is Publisher
. You can create one with let publisher = Publisher::new(10)
. This implements
the Sink
trait so can be used in a very similar way to send messages. The number passed in is the maximum number
of waiting messages allowed for any given subscriber.
A subscription can be created using let subscription = publisher.subscribe()
. Any messages sent to the sink after
this is called is relayed to all subscriptions. A subscription is a Stream
so can interact with other parts of the
futures library in the usual way.
Here's a full worked example with a single subscriber:
```Rust let publisher = Publisher::new(10); let mut publisher = executor::spawn(publisher);
let subscriber = publisher.subscribe(); let mut subscriber = executor::spawn(subscriber);
publisher.waitsend(1).unwrap(); publisher.waitsend(2).unwrap(); publisher.wait_send(3).unwrap();
assert!(subscriber.waitstream() == Some(Ok(1))); assert!(subscriber.waitstream() == Some(Ok(2))); assert!(subscriber.wait_stream() == Some(Ok(3))); ```
It's also possible to call subscriber.clone()
to create a new subscription from an existing one without needing to
keep a reference to the publisher. This can be used to reduce the amount of effort needed in passing objects around, and
to hide implementation details from the caller.