Add Beacon API endpoint to download blobs by block ID

beacon_node/http_api/src/lib.rs

@@ -3324,6 +3324,41 @@ pub fn serve<T: BeaconChainTypes>(
             )))
         });
 
+    // GET lighthouse/beacon/blob_sidecars/{block_id}
+    let get_blob_sidecars = warp::path("lighthouse")
+        .and(warp::path("beacon"))
+        .and(warp::path("blob_sidecars"))
+        .and(block_id_or_err)
+        .and(warp::path::end())
+        .and(chain_filter.clone())
+        .and(warp::header::optional::<api_types::Accept>("accept"))
+        .and_then(
+            |block_id: BlockId,
+             chain: Arc<BeaconChain<T>>,
+             accept_header: Option<api_types::Accept>| {
+                async move {
+                    let blobs_sidecar = block_id.blobs_sidecar(&chain).await?;
+
+                    match accept_header {
+                        Some(api_types::Accept::Ssz) => Response::builder()
+                            .status(200)
+                            .header("Content-Type", "application/octet-stream")
+                            .body(blobs_sidecar.as_ssz_bytes().into())
+                            .map_err(|e| {
+                                warp_utils::reject::custom_server_error(format!(
+                                    "failed to create response: {}",
+                                    e
+                                ))
+                            }),
+                        _ => Ok(warp::reply::json(&api_types::GenericResponse::from(
+                            blobs_sidecar,
+                        ))
+                        .into_response()),
+                    }
+                }
+            },
+        );
+
     let get_events = eth_v1
         .and(warp::path("events"))
         .and(warp::path::end())