From e7f3a0ebbe2ba473054762b0dc05309380004aea Mon Sep 17 00:00:00 2001
From: Stuart Innes <37293383+obashistu@users.noreply.github.com>
Date: Sun, 18 Nov 2018 19:27:57 +0000
Subject: [PATCH] Update json.go

Current it is not possible to tell the default JSON binder to use DisallowUnknownFields (supported by jsoniter and default Go json decoder). Use package variable EnableDecoderKnownFieldsOnly as a switch.
---
 binding/json.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/binding/json.go b/binding/json.go
index 310922c1..da92cb9d 100644
--- a/binding/json.go
+++ b/binding/json.go
@@ -17,6 +17,10 @@ import (
 // interface{} as a Number instead of as a float64.
 var EnableDecoderUseNumber = false
 
+// EnableDecoderKnownFieldsOnly is used to toggle DisallowUnknownFields
+// which is disabled by default
+var EnableDecoderKnownFieldsOnly = false
+
 type jsonBinding struct{}
 
 func (jsonBinding) Name() string {
@@ -36,6 +40,9 @@ func decodeJSON(r io.Reader, obj interface{}) error {
 	if EnableDecoderUseNumber {
 		decoder.UseNumber()
 	}
+	if EnableDecoderKnownFieldsOnly {
+		decoder.DisallowUnknownFields()
+	}
 	if err := decoder.Decode(obj); err != nil {
 		return err
 	}