From a6ec27b40d26a056979c9e271b1b3ba56dcdf283 Mon Sep 17 00:00:00 2001
From: Denis Kirillov <denis@nspcc.ru>
Date: Tue, 29 Jun 2021 16:40:26 +0300
Subject: [PATCH] [#93] Object ETag support

Signed-off-by: Denis Kirillov <denis@nspcc.ru>
---
 api/handler/copy.go |  2 +-
 api/handler/get.go  |  7 ++++---
 api/handler/list.go |  4 ++--
 api/handler/put.go  | 14 ++++++++------
 api/layer/object.go |  9 +++++++++
 api/layer/util.go   |  2 ++
 6 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/api/handler/copy.go b/api/handler/copy.go
index 3468159..460c93e 100644
--- a/api/handler/copy.go
+++ b/api/handler/copy.go
@@ -81,7 +81,7 @@ func (h *handler) CopyObjectHandler(w http.ResponseWriter, r *http.Request) {
 		}, r.URL)
 
 		return
-	} else if err = api.EncodeToResponse(w, &CopyObjectResponse{LastModified: inf.Created.Format(time.RFC3339)}); err != nil {
+	} else if err = api.EncodeToResponse(w, &CopyObjectResponse{LastModified: inf.Created.Format(time.RFC3339), ETag: inf.HashSum}); err != nil {
 		h.log.Error("something went wrong",
 			zap.String("request_id", rid),
 			zap.String("dst_bucket_name", bkt),
diff --git a/api/handler/get.go b/api/handler/get.go
index 93cc7f2..7e03222 100644
--- a/api/handler/get.go
+++ b/api/handler/get.go
@@ -109,9 +109,10 @@ func fetchRangeHeader(headers http.Header, fullSize uint64) (*layer.RangeParams,
 }
 
 func writeHeaders(h http.Header, info *layer.ObjectInfo) {
-	h.Set("Content-Type", info.ContentType)
-	h.Set("Last-Modified", info.Created.Format(http.TimeFormat))
-	h.Set("Content-Length", strconv.FormatInt(info.Size, 10))
+	h.Set(api.ContentType, info.ContentType)
+	h.Set(api.LastModified, info.Created.Format(http.TimeFormat))
+	h.Set(api.ContentLength, strconv.FormatInt(info.Size, 10))
+	h.Set(api.ETag, info.HashSum)
 
 	for key, val := range info.Headers {
 		h.Set("X-"+key, val)
diff --git a/api/handler/list.go b/api/handler/list.go
index a05257f..3212f49 100644
--- a/api/handler/list.go
+++ b/api/handler/list.go
@@ -196,7 +196,7 @@ func encodeV1(arg *listObjectsArgs, list *layer.ListObjectsInfo) *ListObjectsRes
 				DisplayName: obj.Owner.String(),
 			},
 
-			// ETag:         "",
+			ETag: obj.HashSum,
 			// StorageClass: "",
 		})
 	}
@@ -259,7 +259,7 @@ func encodeV2(arg *listObjectsArgs, list *layer.ListObjectsInfo) *ListObjectsV2R
 				DisplayName: obj.Owner.String(),
 			},
 
-			// ETag:         "",
+			ETag: obj.HashSum,
 			// StorageClass: "",
 		})
 	}
diff --git a/api/handler/put.go b/api/handler/put.go
index 2df676e..cae8a8d 100644
--- a/api/handler/put.go
+++ b/api/handler/put.go
@@ -24,11 +24,12 @@ const (
 
 func (h *handler) PutObjectHandler(w http.ResponseWriter, r *http.Request) {
 	var (
-		err error
-		req = mux.Vars(r)
-		bkt = req["bucket"]
-		obj = req["object"]
-		rid = api.GetRequestID(r.Context())
+		err  error
+		info *layer.ObjectInfo
+		req  = mux.Vars(r)
+		bkt  = req["bucket"]
+		obj  = req["object"]
+		rid  = api.GetRequestID(r.Context())
 	)
 
 	if _, err := h.obj.GetBucketInfo(r.Context(), bkt); err != nil {
@@ -53,7 +54,7 @@ func (h *handler) PutObjectHandler(w http.ResponseWriter, r *http.Request) {
 		Size:   r.ContentLength,
 	}
 
-	if _, err = h.obj.PutObject(r.Context(), params); err != nil {
+	if info, err = h.obj.PutObject(r.Context(), params); err != nil {
 		h.log.Error("could not upload object",
 			zap.String("request_id", rid),
 			zap.String("bucket_name", bkt),
@@ -69,6 +70,7 @@ func (h *handler) PutObjectHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	w.Header().Set(api.ETag, info.HashSum)
 	api.WriteSuccessResponseHeadersOnly(w)
 }
 
diff --git a/api/layer/object.go b/api/layer/object.go
index 738d2bd..4fe56f9 100644
--- a/api/layer/object.go
+++ b/api/layer/object.go
@@ -142,6 +142,14 @@ func (n *layer) objectPut(ctx context.Context, p *PutObjectParams) (*ObjectInfo,
 		return nil, err
 	}
 
+	addr := object.NewAddress()
+	addr.SetObjectID(oid)
+	addr.SetContainerID(bkt.CID)
+	meta, err := n.objectHead(ctx, addr)
+	if err != nil {
+		return nil, err
+	}
+
 	return &ObjectInfo{
 		id: oid,
 
@@ -152,6 +160,7 @@ func (n *layer) objectPut(ctx context.Context, p *PutObjectParams) (*ObjectInfo,
 		Created:     time.Now(),
 		Headers:     p.Header,
 		ContentType: r.contentType,
+		HashSum:     meta.PayloadChecksum().String(),
 	}, nil
 }
 
diff --git a/api/layer/util.go b/api/layer/util.go
index 90f9ddb..7ef2faf 100644
--- a/api/layer/util.go
+++ b/api/layer/util.go
@@ -22,6 +22,7 @@ type (
 		Size        int64
 		ContentType string
 		Created     time.Time
+		HashSum     string
 		Owner       *owner.ID
 		Headers     map[string]string
 	}
@@ -119,6 +120,7 @@ func objectInfoFromMeta(bkt *BucketInfo, meta *object.Object, prefix, delimiter
 		Headers:     userHeaders,
 		Owner:       meta.OwnerID(),
 		Size:        size,
+		HashSum:     meta.PayloadChecksum().String(),
 	}
 }