From 9ef9b6f90d02d7c0e2dbdef3ed4f38748271b6d4 Mon Sep 17 00:00:00 2001
From: Mohan Raj <praem1990@gmail.com>
Date: Fri, 22 Sep 2023 11:29:54 +0530
Subject: [PATCH] Set ContentLength=0 when body is nil and setContentLength is
 true (#698)

---
 client_test.go | 11 +++++++++++
 middleware.go  |  8 ++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/client_test.go b/client_test.go
index da098fbc..4a27ecf2 100644
--- a/client_test.go
+++ b/client_test.go
@@ -488,6 +488,17 @@ func TestClientOptions(t *testing.T) {
 	assertEqual(t, client.closeConnection, true)
 }
 
+func TestContentLengthWhenBodyIsNil(t *testing.T) {
+	client := dc()
+
+	client.SetPreRequestHook(func(c *Client, r *http.Request) error {
+		assertEqual(t, "0", r.Header.Get(hdrContentLengthKey))
+		return nil
+	})
+
+	client.R().SetContentLength(true).SetBody(nil).Get("http://localhost")
+}
+
 func TestClientPreRequestHook(t *testing.T) {
 	client := dc()
 	client.SetPreRequestHook(func(c *Client, r *http.Request) error {
diff --git a/middleware.go b/middleware.go
index 9b19c463..2b33b134 100644
--- a/middleware.go
+++ b/middleware.go
@@ -166,8 +166,12 @@ func parseRequestBody(c *Client, r *Request) (err error) {
 
 CL:
 	// by default resty won't set content length, you can if you want to :)
-	if (c.setContentLength || r.setContentLength) && r.bodyBuf != nil {
-		r.Header.Set(hdrContentLengthKey, fmt.Sprintf("%d", r.bodyBuf.Len()))
+	if c.setContentLength || r.setContentLength {
+		if r.bodyBuf == nil {
+			r.Header.Set(hdrContentLengthKey, "0")
+		} else {
+			r.Header.Set(hdrContentLengthKey, fmt.Sprintf("%d", r.bodyBuf.Len()))
+		}
 	}
 
 	return