From 5d1f4c1c62ec3612fb9d9b951f7a8c458dd44e26 Mon Sep 17 00:00:00 2001
From: Takato Fukui <50371596+eyasy1217@users.noreply.github.com>
Date: Wed, 24 Jan 2024 10:23:37 +0900
Subject: [PATCH] Parse request body when using X-HTTP-Method-Override header
 (#3918)

---
 runtime/mux.go      |  2 +-
 runtime/mux_test.go | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/runtime/mux.go b/runtime/mux.go
index 628e1fde1cb..ed9a7e4387d 100644
--- a/runtime/mux.go
+++ b/runtime/mux.go
@@ -341,13 +341,13 @@ func (s *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if override := r.Header.Get("X-HTTP-Method-Override"); override != "" && s.isPathLengthFallback(r) {
-		r.Method = strings.ToUpper(override)
 		if err := r.ParseForm(); err != nil {
 			_, outboundMarshaler := MarshalerForRequest(s, r)
 			sterr := status.Error(codes.InvalidArgument, err.Error())
 			s.errorHandler(ctx, s, outboundMarshaler, w, r, sterr)
 			return
 		}
+		r.Method = strings.ToUpper(override)
 	}
 
 	var pathComponents []string
diff --git a/runtime/mux_test.go b/runtime/mux_test.go
index 62dd7f40fd0..298f68c814f 100644
--- a/runtime/mux_test.go
+++ b/runtime/mux_test.go
@@ -607,6 +607,19 @@ func TestMuxServeHTTP(t *testing.T) {
 	}
 }
 
+func TestServeHTTP_WithMethodOverrideAndFormParsing(t *testing.T) {
+	r := httptest.NewRequest("POST", "/foo", strings.NewReader("bar=hoge"))
+	r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	r.Header.Set("X-HTTP-Method-Override", "GET")
+	w := httptest.NewRecorder()
+
+	runtime.NewServeMux().ServeHTTP(w, r)
+
+	if r.FormValue("bar") != "hoge" {
+		t.Error("form is not parsed")
+	}
+}
+
 var defaultHeaderMatcherTests = []struct {
 	name     string
 	in       string