Merge pull request #158 from thomastaylor312/fix/sized_stream

Cargo.toml

@@ -17,7 +17,7 @@ license = "Apache-2.0"
 name = "oci-client"
 readme = "README.md"
 repository = "https://github.com/oras-project/rust-oci-client"
-version = "0.12.0"
+version = "0.12.1"
 
 [badges]
 maintenance = { status = "actively-developed" }

src/blob.rs

@@ -2,6 +2,7 @@
 use std::task::Poll;
 
 use futures_util::stream::{BoxStream, Stream};
+use futures_util::TryStreamExt;
 
 use crate::digest::Digester;
 use crate::errors::DigestError;
@@ -14,6 +15,17 @@ pub struct SizedStream {
     pub stream: BoxStream<'static, Result<bytes::Bytes, std::io::Error>>,
 }
 
+impl Stream for SizedStream {
+    type Item = Result<bytes::Bytes, std::io::Error>;
+
+    fn poll_next(
+        mut self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> Poll<Option<Self::Item>> {
+        self.stream.try_poll_next_unpin(cx)
+    }
+}
+
 /// The response of a partial blob request
 pub enum BlobResponse {
     /// The response is a full blob (for example when partial requests aren't supported)

src/client.rs

@@ -1089,8 +1089,33 @@ impl Client {
 
     /// Stream a single layer from an OCI registry.
     ///
-    /// This is a streaming version of [`Client::pull_blob`].
-    /// Returns [`Stream`](futures_util::Stream).
+    /// This is a streaming version of [`Client::pull_blob`]. Returns [`SizedStream`], which
+    /// implements [`Stream`](futures_util::Stream) or can be used directly to get the content
+    /// length of the response
+    ///
+    /// # Example
+    /// ```rust
+    /// use std::future::Future;
+    /// use std::io::Error;
+    ///
+    /// use futures_util::TryStreamExt;
+    /// use oci_client::{Client, Reference};
+    /// use oci_client::client::ClientConfig;
+    /// use oci_client::manifest::OciDescriptor;
+    ///
+    /// async {
+    ///   let client = Client::new(Default::default());
+    ///   let imgRef: Reference = "busybox:latest".parse().unwrap();
+    ///   let desc = OciDescriptor { digest: "sha256:deadbeef".to_owned(), ..Default::default() };
+    ///   let mut stream = client.pull_blob_stream(&imgRef, &desc).await.unwrap();
+    ///   // Check the optional content length
+    ///   let content_length = stream.content_length.unwrap_or_default();
+    ///   // Use as a stream
+    ///   stream.try_next().await.unwrap().unwrap();
+    ///   // Use the underlying stream
+    ///   let mut stream = stream.stream;
+    /// };
+    /// ```
     pub async fn pull_blob_stream(
         &self,
         image: &Reference,