diff --git a/web/api/query.go b/web/api/query.go
index f007cd97a..9448acc3b 100644
--- a/web/api/query.go
+++ b/web/api/query.go
@@ -25,8 +25,8 @@ import (
 	"time"
 )
 
-func (serv MetricsService) Query(Expr string, Json string) (result string) {
-	exprNode, err := rules.LoadExprFromString(Expr)
+func (serv MetricsService) Query(expr string, formatJson string) (result string) {
+	exprNode, err := rules.LoadExprFromString(expr)
 	if err != nil {
 		return ast.ErrorToJSON(err)
 	}
@@ -35,7 +35,7 @@ func (serv MetricsService) Query(Expr string, Json string) (result string) {
 
 	rb := serv.ResponseBuilder()
 	var format ast.OutputFormat
-	if Json != "" {
+	if formatJson != "" {
 		format = ast.JSON
 		rb.SetContentType(gorest.Application_Json)
 	} else {
@@ -46,8 +46,8 @@ func (serv MetricsService) Query(Expr string, Json string) (result string) {
 	return ast.EvalToString(exprNode, &timestamp, format)
 }
 
-func (serv MetricsService) QueryRange(Expr string, End int64, Range int64, Step int64) string {
-	exprNode, err := rules.LoadExprFromString(Expr)
+func (serv MetricsService) QueryRange(expr string, end int64, duration int64, step int64) string {
+	exprNode, err := rules.LoadExprFromString(expr)
 	if err != nil {
 		return ast.ErrorToJSON(err)
 	}
@@ -57,26 +57,26 @@ func (serv MetricsService) QueryRange(Expr string, End int64, Range int64, Step
 	rb := serv.ResponseBuilder()
 	rb.SetContentType(gorest.Application_Json)
 
-	if End == 0 {
-		End = serv.time.Now().Unix()
+	if end == 0 {
+		end = serv.time.Now().Unix()
 	}
 
-	if Step < 1 {
-		Step = 1
+	if step < 1 {
+		step = 1
 	}
 
-	if End-Range < 0 {
-		Range = End
+	if end-duration < 0 {
+		duration = end
 	}
 
 	// Align the start to step "tick" boundary.
-	End -= End % Step
+	end -= end % step
 
 	matrix := ast.EvalVectorRange(
 		exprNode.(ast.VectorNode),
-		time.Unix(End-Range, 0),
-		time.Unix(End, 0),
-		time.Duration(Step)*time.Second)
+		time.Unix(end-duration, 0),
+		time.Unix(end, 0),
+		time.Duration(step)*time.Second)
 
 	sort.Sort(matrix)
 	return ast.TypedValueToJSON(matrix, "matrix")