oci: metadata encode/decode (fix; unit)

Signed-off-by: Alex Aizman <alex.aizman@gmail.com>

Author: alex-aizman

ais/test/oci/unit_test.go

@@ -0,0 +1,34 @@
+// Package oci unit test.
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION. All rights reserved.
+ */
+package oci_test
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/NVIDIA/aistore/cmn"
+)
+
+func TestOCIUserMetadataEncodeDecode(t *testing.T) {
+	in := map[string]string{"foo": "bar", "X-Num": "42"}
+	hdr := cmn.BackendHelpers.OCI.EncodeMetadata(in)
+	if len(hdr) != 2 {
+		t.Fatalf("expected 2 headers, got %d", len(hdr))
+	}
+	if _, ok := hdr["Opc-Meta-Foo"]; !ok {
+		t.Fatalf("missing Opc-Meta-Foo, got keys: %v", hdr)
+	}
+	if _, ok := hdr["Opc-Meta-X-Num"]; !ok {
+		t.Fatalf("missing Opc-Meta-X-Num, got keys: %v", hdr)
+	}
+	h := http.Header{}
+	for k, v := range hdr {
+		h.Set(k, v)
+	}
+	out := cmn.BackendHelpers.OCI.DecodeMetadata(h)
+	if out["Foo"] != "bar" || out["X-Num"] != "42" {
+		t.Fatalf("round-trip mismatch: %+v", out)
+	}
+}

cmn/backend.go

@@ -35,6 +35,11 @@ const AwsMultipartDelim = "-"
 // - https://docs.aws.amazon.com/AmazonS3/latest/userguide/UsingMetadata.html#UserMetadata
 const AwsHeaderMetaPrefix = "X-Amz-Meta-"
 
+// OCI Object Storage user metadata
+// from: https://docs.oracle.com/en-us/iaas/Content/Object/Tasks/managingobjects.htm
+// User metadata uses the "opc-meta-" prefix (canonicalized to "Opc-Meta-").
+const OCIHeaderMetaPrefix = "Opc-Meta-"
+
 func isS3MultipartEtag(etag string) bool {
 	return strings.Contains(etag, AwsMultipartDelim)
 }
@@ -210,14 +215,24 @@ var BackendHelpers = struct {
 				return "", false
 			}
 		},
-
+		EncodeMetadata: func(metadata map[string]string) (header map[string]string) {
+			if len(metadata) == 0 {
+				return
+			}
+			header = make(map[string]string, len(metadata))
+			for k, v := range metadata {
+				key := http.CanonicalHeaderKey(OCIHeaderMetaPrefix + k)
+				header[key] = v
+			}
+			return
+		},
 		DecodeMetadata: func(header http.Header) (metadata map[string]string) {
 			for headerKey := range header {
-				if strings.HasPrefix(headerKey, AwsHeaderMetaPrefix) {
+				if strings.HasPrefix(headerKey, OCIHeaderMetaPrefix) {
 					if metadata == nil {
 						metadata = make(map[string]string)
 					}
-					key := strings.TrimPrefix(headerKey, AwsHeaderMetaPrefix)
+					key := strings.TrimPrefix(headerKey, OCIHeaderMetaPrefix)
 					value := header.Get(headerKey)
 					metadata[key] = value
 				}