Crate split_stream_by

This repo is for a rust crate that offers a futures::Stream extension trait which allows for splitting a Stream into two streams using a predicate function thats checked on each Stream::Item.

The current version of this crate buffers only one value and only in the scenario where the item yielded from the parent stream is not what the child stream requested per the predicate. In that scenario, the item is stored and the other stream is awakened

use split_stream_by::SplitStreamByExt;

let incoming_stream = futures::stream::iter([0,1,2,3,4,5]);
let (mut even_stream, mut odd_stream) = incoming_stream.split_by(|&n| n % 2 == 0);

tokio::spawn(async move {
	while let Some(even_number) = even_stream.next().await {
		println!("Even {}",even_number);
	}
});

while let Some(odd_number) = odd_stream.next().await {
	println!("Odd {}",odd_number);
}

A more advanced usage uses split_by_map which allows for extracting values while splitting

use split_stream_by::{Either,SplitStreamByExt};

struct Request {
	//...
}

struct Response {
	//...
}

enum Message {
	Request(Request),
	Response(Response)
}

let incoming_stream = futures::stream::iter([
	Message::Request(Request {}),
	Message::Response(Response {}),
	Message::Response(Response {}),
]);
let (mut request_stream, mut response_stream) = incoming_stream.split_by_map(|item| match item {
	Message::Request(req) => Either::Left(req),
	Message::Response(res) => Either::Right(res),
});

tokio::spawn(async move {
	while let Some(request) = request_stream.next().await {
		// ...
	}
});

while let Some(response) = response_stream.next().await {
	// ...
}

Structs

FalseSplitBy

A struct that implements Stream which returns the items where the predicate returns false

LeftSplitByMap

A struct that implements Stream which returns the inner values where the predicate returns Either::Left(..) when using split_by_map

RightSplitByMap

A struct that implements Stream which returns the inner values where the predicate returns Either::Right(..) when using split_by_map

TrueSplitBy

A struct that implements Stream which returns the items where the predicate returns true

Enums

Either

Combines two different futures, streams, or sinks having the same associated types into a single type.

Traits

SplitStreamByExt

This is the extension crate would provides the functionality for splitting a stream