[#87] Allow canonical X-Attribute-Neofs-* headers

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

README.md

@@ -357,7 +357,8 @@ You can also add some attributes to your file using the following rules:
    "X-Attribute-" prefix stripped, that is if you add "X-Attribute-Ololo:
    100500" header to your request the resulting object will get "Ololo:
    100500" attribute
- * "X-Attribute-NEOFS-*" headers are special, they're used to set internal
+ * "X-Attribute-NEOFS-*" headers are special 
+   (`-NEOFS-` part can also be `-neofs-` or`-Neofs-`), they're used to set internal
    NeoFS attributes starting with `__NEOFS__` prefix, for these attributes all
    dashes get converted to underscores and all letters are capitalized. For
    example, you can use "X-Attribute-NEOFS-Expiration-Epoch" header to set

uploader/filter.go

@@ -9,14 +9,14 @@ import (
 
 const (
 	userAttributeHeaderPrefix = "X-Attribute-"
-	neofsAttributeHeaderPrefix = "NEOFS-"
-
 	systemAttributePrefix     = "__NEOFS__"
 )
 
-func systemTranslator(key []byte) []byte {
-	// replace `NEOFS-` with `__NEOFS__`
-	key = bytes.Replace(key, []byte(neofsAttributeHeaderPrefix), []byte(systemAttributePrefix), 1)
+var neofsAttributeHeaderPrefixes = [...][]byte{[]byte("Neofs-"), []byte("NEOFS-"), []byte("neofs-")}
+
+func systemTranslator(key, prefix []byte) []byte {
+	// replace specified prefix with `__NEOFS__`
+	key = bytes.Replace(key, prefix, []byte(systemAttributePrefix), 1)
 
 	// replace `-` with `_`
 	key = bytes.ReplaceAll(key, []byte("-"), []byte("_"))
@@ -28,7 +28,6 @@ func systemTranslator(key []byte) []byte {
 func filterHeaders(l *zap.Logger, header *fasthttp.RequestHeader) map[string]string {
 	result := make(map[string]string)
 	prefix := []byte(userAttributeHeaderPrefix)
-	system := []byte(neofsAttributeHeaderPrefix)
 
 	header.VisitAll(func(key, val []byte) {
 		// checks that key and val not empty
@@ -45,8 +44,11 @@ func filterHeaders(l *zap.Logger, header *fasthttp.RequestHeader) map[string]str
 		key = bytes.TrimPrefix(key, prefix)
 
 		// checks that it's a system NeoFS header
+		for _, system := range neofsAttributeHeaderPrefixes {
 			if bytes.HasPrefix(key, system) {
-			key = systemTranslator(key)
+				key = systemTranslator(key, system)
+				break
+			}
 		}
 
 		// checks that attribute key not empty

uploader/filter_test.go

@@ -0,0 +1,32 @@
+package uploader
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neofs-sdk-go/pkg/logger"
+	"github.com/stretchr/testify/require"
+	"github.com/valyala/fasthttp"
+)
+
+func TestFilter(t *testing.T) {
+	log, err := logger.New()
+	require.NoError(t, err)
+
+	req := &fasthttp.RequestHeader{}
+	req.DisableNormalizing()
+	req.Set("X-Attribute-Neofs-Expiration-Epoch1", "101")
+	req.Set("X-Attribute-NEOFS-Expiration-Epoch2", "102")
+	req.Set("X-Attribute-neofs-Expiration-Epoch3", "103")
+	req.Set("X-Attribute-MyAttribute", "value")
+
+	expected := map[string]string{
+		"__NEOFS__EXPIRATION_EPOCH1": "101",
+		"MyAttribute":                "value",
+		"__NEOFS__EXPIRATION_EPOCH3": "103",
+		"__NEOFS__EXPIRATION_EPOCH2": "102",
+	}
+
+	result := filterHeaders(log, req)
+
+	require.Equal(t, expected, result)
+}