From 7d6b2a4740c32c3a07a4ce4204da2debee371bcd Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Sat, 22 Sep 2018 22:12:21 -0700
Subject: [PATCH] add ETag to upload results and chunks

---
 weed/command/filer_copy.go       |  2 ++
 weed/filesys/dirty_page.go       |  1 +
 weed/operation/upload_content.go | 11 +++++++++++
 weed/server/common.go            |  1 +
 4 files changed, 15 insertions(+)

diff --git a/weed/command/filer_copy.go b/weed/command/filer_copy.go
index 218abf645..d7b474628 100644
--- a/weed/command/filer_copy.go
+++ b/weed/command/filer_copy.go
@@ -201,6 +201,7 @@ func uploadFileAsOne(filerAddress, filerGrpcAddress string, urlFolder string, f
 			Offset: 0,
 			Size:   uint64(uploadResult.Size),
 			Mtime:  time.Now().UnixNano(),
+			ETag:   uploadResult.ETag,
 		})
 
 		fmt.Printf("copied %s => http://%s%s%s\n", fileName, filerAddress, urlFolder, fileName)
@@ -278,6 +279,7 @@ func uploadFileInChunks(filerAddress, filerGrpcAddress string, urlFolder string,
 			Offset: i * chunkSize,
 			Size:   uint64(uploadResult.Size),
 			Mtime:  time.Now().UnixNano(),
+			ETag:   uploadResult.ETag,
 		})
 		fmt.Printf("uploaded %s-%d to %s [%d,%d)\n", fileName, i+1, targetUrl, i*chunkSize, i*chunkSize+int64(uploadResult.Size))
 	}
diff --git a/weed/filesys/dirty_page.go b/weed/filesys/dirty_page.go
index eb810d383..8bdb12d4d 100644
--- a/weed/filesys/dirty_page.go
+++ b/weed/filesys/dirty_page.go
@@ -187,6 +187,7 @@ func (pages *ContinuousDirtyPages) saveToStorage(ctx context.Context, buf []byte
 		Offset: offset,
 		Size:   uint64(len(buf)),
 		Mtime:  time.Now().UnixNano(),
+		ETag:   uploadResult.ETag,
 	}, nil
 
 }
diff --git a/weed/operation/upload_content.go b/weed/operation/upload_content.go
index 30c7f1ea3..1fd0ed2b9 100644
--- a/weed/operation/upload_content.go
+++ b/weed/operation/upload_content.go
@@ -22,6 +22,7 @@ type UploadResult struct {
 	Name  string `json:"name,omitempty"`
 	Size  uint32 `json:"size,omitempty"`
 	Error string `json:"error,omitempty"`
+	ETag  string `json:"error,omitempty"`
 }
 
 var (
@@ -90,6 +91,7 @@ func upload_content(uploadUrl string, fillBufferFunction func(w io.Writer) error
 		return nil, post_err
 	}
 	defer resp.Body.Close()
+	etag := getEtag(resp)
 	resp_body, ra_err := ioutil.ReadAll(resp.Body)
 	if ra_err != nil {
 		return nil, ra_err
@@ -103,5 +105,14 @@ func upload_content(uploadUrl string, fillBufferFunction func(w io.Writer) error
 	if ret.Error != "" {
 		return nil, errors.New(ret.Error)
 	}
+	ret.ETag = etag
 	return &ret, nil
 }
+
+func getEtag(r *http.Response) (etag string) {
+	etag = r.Header.Get("ETag")
+	if strings.HasPrefix(etag, "\"") && strings.HasSuffix(etag, "\"") {
+		etag = etag[1 : len(etag)-1]
+	}
+	return
+}
diff --git a/weed/server/common.go b/weed/server/common.go
index 2e3053092..12adbf1b4 100644
--- a/weed/server/common.go
+++ b/weed/server/common.go
@@ -123,6 +123,7 @@ func submitForClientHandler(w http.ResponseWriter, r *http.Request, masterUrl st
 	m["fid"] = assignResult.Fid
 	m["fileUrl"] = assignResult.PublicUrl + "/" + assignResult.Fid
 	m["size"] = uploadResult.Size
+	m["eTag"] = uploadResult.ETag
 	writeJsonQuiet(w, r, http.StatusCreated, m)
 	return
 }