fix: not found page for unknown blobs

apps/block_scout_web/lib/block_scout_web/controllers/api/v2/blob_controller.ex

@@ -2,7 +2,7 @@ defmodule BlockScoutWeb.API.V2.BlobController do
   use BlockScoutWeb, :controller
 
   alias Explorer.Chain
-  alias Explorer.Chain.Beacon.Reader
+  alias Explorer.Chain.Beacon.{Blob, Reader}
 
   action_fallback(BlockScoutWeb.API.V2.FallbackController)
 
@@ -14,16 +14,18 @@ defmodule BlockScoutWeb.API.V2.BlobController do
     with {:format, {:ok, blob_hash}} <- {:format, Chain.string_to_transaction_hash(blob_hash_string)} do
       transaction_hashes = Reader.blob_hash_to_transactions(blob_hash, api?: true)
 
-      case Reader.blob(blob_hash, true, api?: true) do
-        {:ok, blob} ->
-          conn
-          |> put_status(200)
-          |> render(:blob, %{blob: blob, transaction_hashes: transaction_hashes})
+      {status, blob} =
+        case Reader.blob(blob_hash, true, api?: true) do
+          {:ok, blob} -> {:ok, blob}
+          {:error, :not_found} -> {:pending, %Blob{hash: blob_hash}}
+        end
 
-        {:error, :not_found} ->
-          conn
-          |> put_status(200)
-          |> render(:blob, %{transaction_hashes: transaction_hashes})
+      if Enum.empty?(transaction_hashes) and status == :pending do
+        {:error, :not_found}
+      else
+        conn
+        |> put_status(200)
+        |> render(:blob, %{blob: blob, transaction_hashes: transaction_hashes})
       end
     end
   end

apps/block_scout_web/lib/block_scout_web/views/api/v2/blob_view.ex

@@ -7,10 +7,6 @@ defmodule BlockScoutWeb.API.V2.BlobView do
     blob |> prepare_blob() |> Map.put("transaction_hashes", transaction_hashes)
   end
 
-  def render("blob.json", %{transaction_hashes: transaction_hashes}) do
-    %{"transaction_hashes" => transaction_hashes}
-  end
-
   def render("blobs.json", %{blobs: blobs}) do
     %{"items" => Enum.map(blobs, &prepare_blob(&1))}
   end