From 7700ec0b59f404cf69c94e9e474990225c832de6 Mon Sep 17 00:00:00 2001
From: chrislu <chris.lu@gmail.com>
Date: Mon, 17 Nov 2025 01:55:47 -0800
Subject: [PATCH] ensures PUT and GET operations return consistent ETags

---
 weed/s3api/s3api_object_handlers_copy.go |  2 +-
 weed/s3api/s3api_object_handlers_put.go  | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/weed/s3api/s3api_object_handlers_copy.go b/weed/s3api/s3api_object_handlers_copy.go
index 885b71ac0..53fbf547c 100644
--- a/weed/s3api/s3api_object_handlers_copy.go
+++ b/weed/s3api/s3api_object_handlers_copy.go
@@ -84,7 +84,7 @@ func (s3a *S3ApiServer) CopyObjectHandler(w http.ResponseWriter, r *http.Request
 			return
 		}
 		writeSuccessResponseXML(w, r, CopyObjectResult{
-			ETag:         fmt.Sprintf("%x", entry.Attributes.Md5),
+			ETag:         filer.ETag(entry),
 			LastModified: time.Now().UTC(),
 		})
 		return
diff --git a/weed/s3api/s3api_object_handlers_put.go b/weed/s3api/s3api_object_handlers_put.go
index 2d5a14d4a..c9c30558f 100644
--- a/weed/s3api/s3api_object_handlers_put.go
+++ b/weed/s3api/s3api_object_handlers_put.go
@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/pquerna/cachecontrol/cacheobject"
+	"github.com/seaweedfs/seaweedfs/weed/filer"
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/operation"
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
@@ -372,12 +373,11 @@ func (s3a *S3ApiServer) putToFiler(r *http.Request, uploadUrl string, dataReader
 		return "", s3err.ErrInternalError, SSEResponseMetadata{}
 	}
 
-	// Step 3: Calculate ETag and add SSE metadata to chunks
+	// Step 3: Calculate MD5 hash and add SSE metadata to chunks
 	md5Sum := chunkResult.Md5Hash.Sum(nil)
-	etag = fmt.Sprintf("%x", md5Sum)
 
-	glog.Infof("putToFiler: Chunked upload SUCCESS - path=%s, chunks=%d, size=%d, etag=%s",
-		filePath, len(chunkResult.FileChunks), chunkResult.TotalSize, etag)
+	glog.Infof("putToFiler: Chunked upload SUCCESS - path=%s, chunks=%d, size=%d",
+		filePath, len(chunkResult.FileChunks), chunkResult.TotalSize)
 	
 	// Log chunk details for debugging
 	for i, chunk := range chunkResult.FileChunks {
@@ -456,6 +456,12 @@ func (s3a *S3ApiServer) putToFiler(r *http.Request, uploadUrl string, dataReader
 		entry.Attributes.Md5 = md5Sum
 	}
 
+	// Calculate ETag using the same logic as GET to ensure consistency
+	// For single chunk: uses entry.Attributes.Md5
+	// For multiple chunks: uses filer.ETagChunks() which returns "<hash>-<count>"
+	etag = filer.ETag(entry)
+	glog.Infof("putToFiler: Calculated ETag=%s for %d chunks", etag, len(chunkResult.FileChunks))
+
 	// Set object owner
 	amzAccountId := r.Header.Get(s3_constants.AmzAccountId)
 	if amzAccountId != "" {