From 48c163f9d7682b6b6f74693c3a2987839d89a271 Mon Sep 17 00:00:00 2001
From: Sven Augustin <sven.augustin@psi.ch>
Date: Mon, 23 May 2022 12:42:22 +0200
Subject: [PATCH] actually working in-memory conversion to hdf5 file

---
 utils/df_utils.py | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/utils/df_utils.py b/utils/df_utils.py
index d256b04..7114cf0 100644
--- a/utils/df_utils.py
+++ b/utils/df_utils.py
@@ -25,10 +25,20 @@ def to_excel_binary(df, **kwargs):
         res = out.getvalue()
     return res
 
-def to_hdf_binary(df, key="df", **kwargs):
-    with BytesIO() as out:
-        df.to_hdf(out, key, **kwargs)
-        res = out.getvalue()
+
+
+from pandas import HDFStore
+
+
+def to_hdf_binary(df):
+    with HDFStore(
+        "wontbewritten.h5",
+        mode="a",
+        driver="H5FD_CORE",
+        driver_core_backing_store=0
+    ) as out:
+        out["/data"] = df
+        res = out._handle.get_file_image()
     return res