Add API to retrieve blobs sidecar

apis/beacon/blobs_sidecar.yaml

@@ -0,0 +1,47 @@
+get:
+  operationId: getBlobsSidecar
+  summary: Get Blobs Sidecar
+  description: |
+    Returns the `BlobsSidecar` for a given block ID.
+    Depending on `Accept` header it can be returned either as JSON or SSZ-serialized bytes.
+  tags:
+    - Beacon
+  parameters:
+    - name: block_id
+      in: path
+      required: true
+      $ref: '../../../beacon-node-oapi.yaml#/components/parameters/BlockId'
+  responses:
+    "200":
+      description: "Successful response"
+      content:
+        application/json:
+          schema:
+            title: GetBlobsSidecarResponse
+            type: object
+            properties:
+              data:
+                $ref: '../../beacon-node-oapi.yaml#/components/schemas/BlobsSidecar'
+        application/octet-stream:
+          schema:
+            description: "SSZ serialized BlobsSidecar bytes. Use Accept header to choose this response type"
+    "400":
+      description: "The block ID supplied could not be parsed"
+      content:
+        application/json:
+          schema:
+            $ref: "../../../beacon-node-oapi.yaml#/components/schemas/ErrorMessage"
+            example:
+              code: 400
+              message: "Invalid block ID: current"
+     "404":
+      description: "Blobs Sidecar not found"
+      content:
+        application/json:
+          schema:
+            $ref: "../../../beacon-node-oapi.yaml#/components/schemas/ErrorMessage"
+            example:
+              code: 404
+              message: "BlobsSidecar not found"
+     "500":
+      $ref: "../../../beacon-node-oapi.yaml#/components/responses/InternalError"

beacon-node-oapi.yaml

@@ -125,6 +125,8 @@ paths:
     $ref: "./apis/beacon/pool/voluntary_exists.yaml"
   /eth/v1/beacon/pool/bls_to_execution_changes:
     $ref: "./apis/beacon/pool/bls_to_execution_changes.yaml"
+  /eth/v1/beacon/blobs_sidecar:
+    $ref: "./apis/beacon/blobs_sidecar.yaml"
 
   /eth/v2/debug/beacon/states/{state_id}:
     $ref: './apis/debug/state.v2.yaml'
@@ -345,6 +347,8 @@ components:
       $ref: './types/rewards.yaml#/BlockRewards'
     AttestationsRewards:
       $ref: './types/rewards.yaml#/AttestationsRewards'
+    BlobsSidecar:
+      $ref: './types/eip4844/block_and_blobs_sidecar.yaml#/EIP4844/BlobsSidecar'
 
   parameters:
     StateId: