Fix for headers-only CCDB uploads

Author: shahor02

CCDB/src/CcdbApi.cxx

@@ -375,6 +375,10 @@ int CcdbApi::storeAsBinaryFile(const char* buffer, size_t size, const std::strin
     sanitizedEndValidityTimestamp = getFutureTimestamp(60 * 60 * 24 * 1);
   }
   if (mInSnapshotMode) { // write local file
+    if (filename.empty() || buffer == nullptr || size == 0) {
+      LOGP(alarm, "Snapshot mode does not support headers-only upload");
+      return -3;
+    }
     auto pthLoc = getSnapshotDir(mSnapshotTopPath, path);
     o2::utils::createDirectoriesIfAbsent(pthLoc);
     auto flLoc = getSnapshotFile(mSnapshotTopPath, path, filename);
@@ -418,8 +422,14 @@ int CcdbApi::storeAsBinaryFile(const char* buffer, size_t size, const std::strin
     auto mime = curl_mime_init(curl);
     auto field = curl_mime_addpart(mime);
     curl_mime_name(field, "send");
-    curl_mime_filedata(field, filename.c_str());
-    curl_mime_data(field, buffer, size);
+    if (filename.empty()) {
+      curl_mime_filedata(field, filename.c_str());
+    }
+    if (buffer != nullptr && size > 0) {
+      curl_mime_data(field, buffer, size);
+    } else {
+      curl_mime_data(field, "", 0);
+    }
 
     struct curl_slist* headerlist = nullptr;
     static const char buf[] = "Expect:";

CCDB/src/UploadTool.cxx

@@ -148,6 +148,9 @@ int main(int argc, char* argv[])
   }
 
   if (filename == "headersOnly") {
+    auto ent = meta.find("Redirect");
+    std::cout << " Uploading a headers-only object to path " << path << " with timestamp validity from " << starttimestamp << " to " << endtimestamp
+              << " Redirection to: " << ((ent != meta.end()) ? ent->second : std::string{"none"}) << "\n";
     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, "", "", meta, starttimestamp, endtimestamp);