Stream items in api

crates/pile-dataset/src/serve/item.rs

@@ -1,4 +1,5 @@
 use axum::{
+	body::Body,
 	extract::{Query, State},
 	http::{StatusCode, header},
 	response::{IntoResponse, Response},
@@ -7,6 +8,8 @@ use pile_config::Label;
 use pile_value::value::AsyncReader;
 use serde::Deserialize;
 use std::{sync::Arc, time::Instant};
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::ReceiverStream;
 use tracing::debug;
 use utoipa::ToSchema;
 
@@ -67,8 +70,28 @@ pub async fn item_get(
 		time_ms = start.elapsed().as_millis()
 	);
 
-	match reader.read_to_end().await {
-		Ok(bytes) => (StatusCode::OK, [(header::CONTENT_TYPE, mime)], bytes).into_response(),
-		Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, format!("{e:?}")).into_response(),
+	let (tx, rx) = mpsc::channel::<Result<Vec<u8>, std::io::Error>>(8);
+
+	tokio::spawn(async move {
+		// 1MiB chunks
+		let mut buf = vec![0u8; 65536 * 8];
+
+		loop {
+			match reader.read(&mut buf).await {
+				Ok(0) => break,
+				Ok(n) => {
+					if tx.send(Ok(buf[..n].to_vec())).await.is_err() {
+						break;
 					}
 				}
+				Err(e) => {
+					let _ = tx.send(Err(e)).await;
+					break;
+				}
+			}
+		}
+	});
+
+	let body = Body::from_stream(ReceiverStream::new(rx));
+	(StatusCode::OK, [(header::CONTENT_TYPE, mime)], body).into_response()
+}