return new offset after successful PATCH request

concat_test.go

@@ -132,7 +132,7 @@ func (s concatFinalStore) GetReader(id string) (io.Reader, error) {
 	return nil, ErrNotFound
 }
 
-func (s concatFinalStore) WriteChunk(id string, offset int64, src io.Reader) error {
+func (s concatFinalStore) WriteChunk(id string, offset int64, src io.Reader) (int64, error) {
 	if id != "foo" {
 		s.t.Error("unexpected file id")
 	}
@@ -146,7 +146,7 @@ func (s concatFinalStore) WriteChunk(id string, offset int64, src io.Reader) err
 		s.t.Error("unexpected content")
 	}
 
-	return nil
+	return 10, nil
 }
 
 func TestConcatFinal(t *testing.T) {

datastore.go

@@ -37,7 +37,8 @@ type DataStore interface {
 	// return an os.ErrNotExist which will be interpretet as a 404 Not Found.
 	// It will also lock resources while they are written to ensure only one
 	// write happens per time.
-	WriteChunk(id string, offset int64, src io.Reader) error
+	// The function call must return the number of bytes written.
+	WriteChunk(id string, offset int64, src io.Reader) (int64, error)
 	// Read the fileinformation used to validate the offset and respond to HEAD
 	// requests. It may return an os.ErrNotExist which will be interpretet as a
 	// 404 Not Found.

filestore/filestore.go

@@ -42,20 +42,20 @@ func (store FileStore) NewUpload(info tusd.FileInfo) (id string, err error) {
 	return
 }
 
-func (store FileStore) WriteChunk(id string, offset int64, src io.Reader) error {
+func (store FileStore) WriteChunk(id string, offset int64, src io.Reader) (int64, error) {
 	file, err := os.OpenFile(store.binPath(id), os.O_WRONLY|os.O_APPEND, defaultFilePerm)
 	if err != nil {
-		return err
+		return 0, err
 	}
 	defer file.Close()
 
 	n, err := io.Copy(file, src)
 	if n > 0 {
 		if err := store.setOffset(id, offset+n); err != nil {
-			return err
+			return 0, err
 		}
 	}
-	return err
+	return n, err
 }
 
 func (store FileStore) GetInfo(id string) (tusd.FileInfo, error) {

filestore/filestore_test.go

@@ -51,10 +51,13 @@ func TestFilestore(t *testing.T) {
 	}
 
 	// Write data to upload
-	err = store.WriteChunk(id, 0, strings.NewReader("hello world"))
+	bytesWritten, err := store.WriteChunk(id, 0, strings.NewReader("hello world"))
 	if err != nil {
 		t.Fatal(err)
 	}
+	if bytesWritten != int64(len("hello world")) {
+		t.Errorf("expected 11 bytes to be written")
+	}
 
 	// Check new offset
 	info, err = store.GetInfo(id)

handler.go

@@ -314,12 +314,15 @@ func (handler *Handler) patchFile(w http.ResponseWriter, r *http.Request) {
 	// Limit the
 	reader := io.LimitReader(r.Body, maxSize)
 
-	err = handler.dataStore.WriteChunk(id, offset, reader)
+	bytesWritten, err := handler.dataStore.WriteChunk(id, offset, reader)
 	if err != nil {
 		handler.sendError(w, err)
 		return
 	}
 
+	// Send new offset to client
+	w.Header().Set("Upload-Offset", strconv.FormatInt(offset+bytesWritten, 10))
+
 	w.WriteHeader(http.StatusNoContent)
 }
 
@@ -462,8 +465,9 @@ func (handler *Handler) fillFinalUpload(id string, uploads []string) error {
 	}
 
 	reader := io.MultiReader(readers...)
+	_, err := handler.dataStore.WriteChunk(id, 0, reader)
 
-	return handler.dataStore.WriteChunk(id, 0, reader)
+	return err
 }
 
 // Parse the Upload-Metadata header as defined in the File Creation extension.

handler_test.go

@@ -12,8 +12,8 @@ type zeroStore struct{}
 func (store zeroStore) NewUpload(info FileInfo) (string, error) {
 	return "", nil
 }
-func (store zeroStore) WriteChunk(id string, offset int64, src io.Reader) error {
+func (store zeroStore) WriteChunk(id string, offset int64, src io.Reader) (int64, error) {
-	return nil
+	return 0, nil
 }
 
 func (store zeroStore) GetInfo(id string) (FileInfo, error) {

patch_test.go

@@ -26,7 +26,7 @@ func (s patchStore) GetInfo(id string) (FileInfo, error) {
 	}, nil
 }
 
-func (s patchStore) WriteChunk(id string, offset int64, src io.Reader) error {
+func (s patchStore) WriteChunk(id string, offset int64, src io.Reader) (int64, error) {
 	if s.called {
 		s.t.Errorf("WriteChunk must be called only once")
 	}
@@ -45,7 +45,7 @@ func (s patchStore) WriteChunk(id string, offset int64, src io.Reader) error {
 		s.t.Errorf("Expected source to be 'hello'")
 	}
 
-	return nil
+	return 5, nil
 }
 
 func TestPatch(t *testing.T) {
@@ -66,6 +66,9 @@ func TestPatch(t *testing.T) {
 		},
 		ReqBody: strings.NewReader("hello"),
 		Code:    http.StatusNoContent,
+		ResHeader: map[string]string{
+			"Upload-Offset": "10",
+		},
 	}).Run(handler, t)
 
 	(&httpTest{
@@ -120,7 +123,7 @@ func (s overflowPatchStore) GetInfo(id string) (FileInfo, error) {
 	}, nil
 }
 
-func (s overflowPatchStore) WriteChunk(id string, offset int64, src io.Reader) error {
+func (s overflowPatchStore) WriteChunk(id string, offset int64, src io.Reader) (int64, error) {
 	if s.called {
 		s.t.Errorf("WriteChunk must be called only once")
 	}
@@ -139,7 +142,7 @@ func (s overflowPatchStore) WriteChunk(id string, offset int64, src io.Reader) e
 		s.t.Errorf("Expected 15 bytes got %v", len(data))
 	}
 
-	return nil
+	return 15, nil
 }
 
 // noEOFReader implements io.Reader, io.Writer, io.Closer but does not return