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fix: S3 GetObject/HeadObject with PartNumber should return object ETag, not part ETag (#7622)

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AWS S3 behavior: when calling GetObject or HeadObject with the PartNumber
query parameter, the ETag header should still return the complete object's
ETag (e.g., 'abc123-4' for a 4-part multipart upload), not the individual
part's ETag.

The previous implementation incorrectly overrode the ETag with the part's
ETag, causing test_multipart_get_part to fail.

This fix removes the ETag override logic while keeping:
- x-amz-mp-parts-count header (correct)
- Content-Length adjusted to part size (correct)
- Range calculation for part boundaries (correct)
This commit is contained in:
Chris Lu
2025-12-04 12:18:57 -08:00
committed by GitHub
parent 8d110b29dd
commit a5ab05ec03
1 changed files with 5 additions and 37 deletions
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42
weed/s3api/s3api_object_handlers.go
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@@ -659,16 +659,14 @@ func (s3a *S3ApiServer) GetObjectHandler(w http.ResponseWriter, r *http.Request)
glog.V(3).Infof("GetObject: Set PartsCount=%d for multipart GET with PartNumber=%d", partsCount, partNumber)
// Calculate the byte range for this part
// Note: ETag is NOT overridden - AWS S3 returns the complete object's ETag
// even when requesting a specific part via PartNumber
var startOffset, endOffset int64
if partInfo != nil {
// Use part boundaries from metadata (accurate for multi-chunk parts)
startOffset = objectEntryForSSE.Chunks[partInfo.StartChunk].Offset
lastChunk := objectEntryForSSE.Chunks[partInfo.EndChunk-1]
endOffset = lastChunk.Offset + int64(lastChunk.Size) - 1
// Override ETag with the part's ETag from metadata
w.Header().Set("ETag", "\""+partInfo.ETag+"\"")
glog.V(3).Infof("GetObject: Override ETag with part %d ETag: %s (from metadata)", partNumber, partInfo.ETag)
} else {
// Fallback: assume 1:1 part-to-chunk mapping (backward compatibility)
chunkIndex := partNumber - 1
@@ -680,15 +678,6 @@ func (s3a *S3ApiServer) GetObjectHandler(w http.ResponseWriter, r *http.Request)
partChunk := objectEntryForSSE.Chunks[chunkIndex]
startOffset = partChunk.Offset
endOffset = partChunk.Offset + int64(partChunk.Size) - 1
// Override ETag with chunk's ETag (fallback)
if partChunk.ETag != "" {
if md5Bytes, decodeErr := base64.StdEncoding.DecodeString(partChunk.ETag); decodeErr == nil {
partETag := fmt.Sprintf("%x", md5Bytes)
w.Header().Set("ETag", "\""+partETag+"\"")
glog.V(3).Infof("GetObject: Override ETag with part %d ETag: %s (fallback from chunk)", partNumber, partETag)
}
}
}
// Check if client supplied a Range header - if so, apply it within the part's boundaries
@@ -2266,7 +2255,7 @@ func (s3a *S3ApiServer) HeadObjectHandler(w http.ResponseWriter, r *http.Request
if partNumberStr != "" {
if partNumber, parseErr := strconv.Atoi(partNumberStr); parseErr == nil && partNumber > 0 {
// Get actual parts count from metadata (not chunk count)
partsCount, partInfo := s3a.getMultipartInfo(objectEntryForSSE, partNumber)
partsCount, _ := s3a.getMultipartInfo(objectEntryForSSE, partNumber)
// Validate part number
if partNumber > partsCount {
@@ -2276,31 +2265,10 @@ func (s3a *S3ApiServer) HeadObjectHandler(w http.ResponseWriter, r *http.Request
}
// Set parts count header
// Note: ETag is NOT overridden - AWS S3 returns the complete object's ETag
// even when requesting a specific part via PartNumber
w.Header().Set(s3_constants.AmzMpPartsCount, strconv.Itoa(partsCount))
glog.V(3).Infof("HeadObject: Set PartsCount=%d for part %d", partsCount, partNumber)
// Override ETag with the part's ETag
if partInfo != nil {
// Use part ETag from metadata (accurate for multi-chunk parts)
w.Header().Set("ETag", "\""+partInfo.ETag+"\"")
glog.V(3).Infof("HeadObject: Override ETag with part %d ETag: %s (from metadata)", partNumber, partInfo.ETag)
} else {
// Fallback: use chunk's ETag (backward compatibility)
chunkIndex := partNumber - 1
if chunkIndex >= len(objectEntryForSSE.Chunks) {
glog.Warningf("HeadObject: Part %d chunk index %d out of range (chunks: %d)", partNumber, chunkIndex, len(objectEntryForSSE.Chunks))
s3err.WriteErrorResponse(w, r, s3err.ErrInvalidPart)
return
}
partChunk := objectEntryForSSE.Chunks[chunkIndex]
if partChunk.ETag != "" {
if md5Bytes, decodeErr := base64.StdEncoding.DecodeString(partChunk.ETag); decodeErr == nil {
partETag := fmt.Sprintf("%x", md5Bytes)
w.Header().Set("ETag", "\""+partETag+"\"")
glog.V(3).Infof("HeadObject: Override ETag with part %d ETag: %s (fallback from chunk)", partNumber, partETag)
}
}
}
}
}