1 unstable release
0.1.0 | Oct 13, 2022 |
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#28 in #bidirectional
108 downloads per month
15KB
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Response Channel
A simple wrapper around the tokio::sync::mpsc
channel to provide a bidirectional response channel.
Usually, instantiating a bidrectional channel is cumbersome and requires a lot of boilerplate.
response_channel
provides a method to create a bidirectional response channel using the same API as creating a regular tokio::sync::mpsc
channel (i.e., by just calling a function).
use tokio::task::spawn;
use tokio::join;
type Message = u8;
type Response = u8;
fn main() {
const BUFFER_SIZE: usize = 10;
let (mut tx, mut rx) = response_channel::channel::<Message, Response>(BUFFER_SIZE, None);
let fut1 = spawn(async move {
for i in 0..10 {
let response = tx.send_await_automatic(i).await.unwrap().unwrap();
assert_eq!(response, i + 1);
};
});
let fut2 = spawn(async move {
while let Some((message, tx)) = rx.recv().await {
let response = message + 1;
tx.send(response).await.unwrap();
};
});
let (res1, res2) = join!(fut1, fut2);
res1.unwrap();
res2.unwrap();
}
Implementation Notes
Multiple response_channel::Sender
s can also exist, each one able to send its own messages to the Receiver
and receive localized responses!
Namely, if one particular response_channel::Sender
sends a message to the Receiver
, other response_channel::Sender
s will not be able to see the response.
The response_channel::Sender
struct internally contains the forwards transmission line, as well as the reverse transmission and reverse receiving line.
The reason why the reverse transmission line needs to be held is so that the response_channel::Sender
can send the transmission line as an argument.
The Receiver
can then take the message (which contains the data and the reverse transmissions line), handle the data, and respond using the given transmission line.
Note that cloning the response_channel::Sender
will clone the internal tokio::sync::mpsc::Sender
(so that the same Receiver
will be hit).
It, however, will create a new reverse channel.
This makes sense since a new channel is being created, so a new reverse channel needs to be created.
Dependencies
~2.3–4MB
~65K SLoC