From 88d47a1d9f331cb21301863239524e48ea629469 Mon Sep 17 00:00:00 2001
From: Misko Lee <misko.lee@bindo.com>
Date: Thu, 26 Oct 2017 23:25:08 +0800
Subject: [PATCH] 1. allow parse form before call binding.Bind()

---
 binding.go | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/binding.go b/binding.go
index 21d14a2..1f7677b 100644
--- a/binding.go
+++ b/binding.go
@@ -113,19 +113,22 @@ var multipartFormBinder requestBinder = defaultMultipartFormBinder
 func defaultMultipartFormBinder(req *http.Request, userStruct FieldMapper) Errors {
 	var errs Errors
 
-	multipartReader, err := req.MultipartReader()
-	if err != nil {
-		errs.Add([]string{}, DeserializationError, err.Error())
-		return errs
-	}
+	if req.MultipartForm == nil {
 
-	form, parseErr := multipartReader.ReadForm(MaxMemory)
-	if parseErr != nil {
-		errs.Add([]string{}, DeserializationError, parseErr.Error())
-		return errs
-	}
+		multipartReader, err := req.MultipartReader()
+		if err != nil {
+			errs.Add([]string{}, DeserializationError, err.Error())
+			return errs
+		}
 
-	req.MultipartForm = form
+		form, parseErr := multipartReader.ReadForm(MaxMemory)
+		if parseErr != nil {
+			errs.Add([]string{}, DeserializationError, parseErr.Error())
+			return errs
+		}
+
+		req.MultipartForm = form
+	}
 
 	return bindForm(req, userStruct, req.MultipartForm.Value, req.MultipartForm.File)
 }