✨ Impl query parameter offset

router/transaction.go

@@ -85,6 +85,19 @@ func (h Handlers) GetTransactions(c echo.Context) error {
 		}
 		limit = limitI
 	}
+	offset := 0
+	if offsetQuery := c.QueryParam("offset"); offsetQuery != "" {
+		offsetI, err := strconv.Atoi(offsetQuery)
+		if err != nil {
+			h.Logger.Info("could not parse limit as integer", zap.Error(err))
+			return echo.NewHTTPError(http.StatusBadRequest, err)
+		}
+		if offsetI < 0 {
+			h.Logger.Info("received negative offset", zap.Int("offset", offsetI))
+			return echo.NewHTTPError(http.StatusBadRequest, fmt.Errorf("negative offset(=%d) is invalid", offsetI))
+		}
+		offset = offsetI
+	}
 	var tag *string
 	if c.QueryParam("tag") != "" {
 		t := c.QueryParam("tag")
@@ -111,6 +124,7 @@ func (h Handlers) GetTransactions(c echo.Context) error {
 		Since:   since,
 		Until:   until,
 		Limit:   limit,
+		Offset:  offset,
 		Tag:     tag,
 		Group:   group,
 		Request: request,