From 4e4f11cf84cce81de6a65cdbc3323f22f150aafc Mon Sep 17 00:00:00 2001
From: wiechula <Jens.Wiechula@cern.ch>
Date: Thu, 4 Dec 2025 21:25:19 +0100
Subject: [PATCH] Add possibility for head only object

In case the file name is set to 'headersOnly' an empty object with only
headers is created. This is e.g. necessary for pure redirect entries.
---
 CCDB/src/UploadTool.cxx | 54 +++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 23 deletions(-)

diff --git a/CCDB/src/UploadTool.cxx b/CCDB/src/UploadTool.cxx
index 44b8d8e20bc7d..83b395bedb046 100644
--- a/CCDB/src/UploadTool.cxx
+++ b/CCDB/src/UploadTool.cxx
@@ -147,33 +147,41 @@ int main(int argc, char* argv[])
     meta[p.first] = p.second;
   }
 
-  TFile f(filename.c_str());
-  auto key = f.GetKey(keyname.c_str());
-  if (key) {
-    // get type of key
-    auto classname = key->GetClassName();
-    auto tcl = TClass::GetClass(classname);
-    auto object = f.Get<void>(keyname.c_str());
-    if (tcl->InheritsFrom("TTree")) {
-      auto tree = static_cast<TTree*>(object);
-      tree->LoadBaskets(0x1L << 32); // make tree memory based
-      tree->SetDirectory(nullptr);
-    }
-    // convert classname to typeinfo
-    // typeinfo
-    auto ti = tcl->GetTypeInfo();
-
-    std::cout << " Uploading an object of type " << key->GetClassName()
-              << " to path " << path << " with timestamp validity from " << starttimestamp
-              << " to " << endtimestamp << "\n";
-
-    api.storeAsTFile_impl(object, *ti, path, meta, starttimestamp, endtimestamp);
+  if (filename == "headersOnly") {
+    api.storeAsBinaryFile(nullptr, 0, "ignored", "", path, meta, starttimestamp, endtimestamp);
     if (!api.isSnapshotMode() && meta.find("adjustableEOV") != meta.end() && meta.find("default") == meta.end()) {
-      o2::ccdb::CcdbObjectInfo oi(path, classname, filename, meta, starttimestamp, endtimestamp);
+      o2::ccdb::CcdbObjectInfo oi(path, "", "", meta, starttimestamp, endtimestamp);
       o2::ccdb::adjustOverriddenEOV(api, oi);
     }
   } else {
-    std::cerr << "Key " << keyname << " does not exist\n";
+    TFile f(filename.c_str());
+    auto key = f.GetKey(keyname.c_str());
+    if (key) {
+      // get type of key
+      auto classname = key->GetClassName();
+      auto tcl = TClass::GetClass(classname);
+      auto object = f.Get<void>(keyname.c_str());
+      if (tcl->InheritsFrom("TTree")) {
+        auto tree = static_cast<TTree*>(object);
+        tree->LoadBaskets(0x1L << 32); // make tree memory based
+        tree->SetDirectory(nullptr);
+      }
+      // convert classname to typeinfo
+      // typeinfo
+      auto ti = tcl->GetTypeInfo();
+
+      std::cout << " Uploading an object of type " << key->GetClassName()
+                << " to path " << path << " with timestamp validity from " << starttimestamp
+                << " to " << endtimestamp << "\n";
+
+      api.storeAsTFile_impl(object, *ti, path, meta, starttimestamp, endtimestamp);
+      if (!api.isSnapshotMode() && meta.find("adjustableEOV") != meta.end() && meta.find("default") == meta.end()) {
+        o2::ccdb::CcdbObjectInfo oi(path, classname, filename, meta, starttimestamp, endtimestamp);
+        o2::ccdb::adjustOverriddenEOV(api, oi);
+      }
+    } else {
+      std::cerr << "Key " << keyname << " does not exist\n";
+    }
   }
 
   return 0;