Close io.Reader if possible

datastore.go

@@ -48,6 +48,8 @@ type DataStore interface {
 	// should not be enabled any call to GetReader should return
 	// tusd.ErrNotImplemented. The length of the resource is determined by
 	// retrieving the offset using GetInfo.
+	// If the returned reader also implements the io.Closer interface, the
+	// Close() method will be invoked once everything has been read.
 	GetReader(id string) (io.Reader, error)
 	// Terminate an upload so any further requests to the resource, both reading
 	// and writing, must return os.ErrNotExist or similar.

get_test.go

@@ -24,7 +24,21 @@ func (s getStore) GetInfo(id string) (FileInfo, error) {
 }
 
 func (s getStore) GetReader(id string) (io.Reader, error) {
-	return strings.NewReader("hello"), nil
+	return reader, nil
+}
+
+type closingStringReader struct {
+	*strings.Reader
+	closed bool
+}
+
+func (reader *closingStringReader) Close() error {
+	reader.closed = true
+	return nil
+}
+
+var reader = &closingStringReader{
+	Reader: strings.NewReader("hello"),
 }
 
 func TestGet(t *testing.T) {
@@ -42,4 +56,8 @@ func TestGet(t *testing.T) {
 			"Content-Length": "5",
 		},
 	}).Run(handler, t)
+
+	if !reader.closed {
+		t.Error("expected reader to be closed")
+	}
 }

handler.go

@@ -383,6 +383,11 @@ func (handler *Handler) getFile(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Length", strconv.FormatInt(info.Offset, 10))
 	w.WriteHeader(http.StatusOK)
 	io.Copy(w, src)
+
+	// Try to close the reader if the io.Closer interface is implemented
+	if closer, ok := src.(io.Closer); ok {
+		closer.Close()
+	}
 }
 
 // Terminate an upload permanently.