allow specifying param name in "url" field tag

Author: willnorris

query/encode.go

@@ -19,9 +19,14 @@ func Values(v interface{}) (url.Values, error) {
 	typ := val.Type()
 	for i := 0; i < typ.NumField(); i++ {
 		sf := typ.Field(i)
-		sv := val.Field(i)
 
-		values.Add(sf.Name, fmt.Sprint(sv.Interface()))
+		name := sf.Tag.Get("url")
+		if name == "" {
+			name = sf.Name
+		}
+
+		sv := val.Field(i)
+		values.Add(name, fmt.Sprint(sv.Interface()))
 	}
 
 	return values, nil

query/encode_test.go

@@ -9,7 +9,7 @@ import (
 
 func TestValues(t *testing.T) {
 	s := struct {
-		A string
+		A string `url:"a"`
 		B int
 	}{"abc", 1}
 	v, err := Values(s)
@@ -18,7 +18,7 @@ func TestValues(t *testing.T) {
 	}
 
 	want := url.Values{
-		"A": {"abc"},
+		"a": {"abc"},
 		"B": {"1"},
 	}
 	if !reflect.DeepEqual(want, v) {