Crate stream_transfer_limit 

Byte-count transfer limits for fallible futures streams.

This crate is intentionally small: it wraps a Stream<Item = Result<T, E>>, counts the bytes yielded by successful chunks, and returns a typed error as soon as the configured transfer limit is exceeded. This is useful when the limit is known only after request routing, authentication, or tenant lookup. The default counter type is usize; use TransferLimit::<u64>::from_limit or TransferLimit::<u128>::from_limit for streams that may exceed pointer-sized byte counts.

use futures::{StreamExt, stream};
use stream_transfer_limit::{TransferLimit, TransferLimitError};

let chunks = stream::iter([
    Ok::<_, std::io::Error>(vec![1, 2]),
    Ok(vec![3, 4, 5]),
]);
let mut chunks = TransferLimit::new(4).wrap(chunks);

assert_eq!(chunks.next().await.unwrap().unwrap(), vec![1, 2]);
assert!(matches!(
    chunks.next().await.unwrap(),
    Err(TransferLimitError::LimitExceeded { limit: 4, actual: 5 })
));
assert!(chunks.next().await.is_none());

Structs

TransferLimit

Builder for applying byte-count transfer limits to fallible streams.

Enums

TransferLimitError

Error returned by a transfer-limited stream.

Traits

ChunkLength

Reports the byte length of a stream chunk.

TransferCounter

Integer type used to count cumulative transfer bytes.

Type Aliases

NoopProgress

Default progress callback type used when no callback is configured.