feat(binding): support custom struct tag (#2720)

* feat(binding): support custom struct tag

Add function `binding.MapFormWithTag` (#2719)

* doc: add 'bind form-data with custom struct tag'

Add 'Bind form-data request with custom struct and custom tag' section (#2719)

* test(binding): add test for MapFromWithTag

binding/form_mapping.go

@@ -34,6 +34,10 @@ func mapForm(ptr interface{}, form map[string][]string) error {
 	return mapFormByTag(ptr, form, "form")
 }
 
+func MapFormWithTag(ptr interface{}, form map[string][]string, tag string) error {
+	return mapFormByTag(ptr, form, tag)
+}
+
 var emptyField = reflect.StructField{}
 
 func mapFormByTag(ptr interface{}, form map[string][]string, tag string) error {

binding/form_mapping_test.go

@@ -145,6 +145,15 @@ func TestMappingForm(t *testing.T) {
 	assert.Equal(t, int(6), s.F)
 }
 
+func TestMapFormWithTag(t *testing.T) {
+	var s struct {
+		F int `externalTag:"field"`
+	}
+	err := MapFormWithTag(&s, map[string][]string{"field": {"6"}}, "externalTag")
+	assert.NoError(t, err)
+	assert.Equal(t, int(6), s.F)
+}
+
 func TestMappingTime(t *testing.T) {
 	var s struct {
 		Time      time.Time