RequestHeader support set no default ContentType (#1218)

header.go

@@ -59,9 +59,10 @@ type ResponseHeader struct {
 type RequestHeader struct {
 	noCopy noCopy //nolint:unused,structcheck
 
-	disableNormalizing bool
-	noHTTP11           bool
-	connectionClose    bool
+	disableNormalizing   bool
+	noHTTP11             bool
+	connectionClose      bool
+	noDefaultContentType bool
 
 	// These two fields have been moved close to other bool fields
 	// for reducing RequestHeader object size.
@@ -943,9 +944,15 @@ func (h *ResponseHeader) resetSkipNormalize() {
 	h.trailer = h.trailer[:0]
 }
 
+// SetNoDefaultContentType allows you to control if a default Content-Type header will be set (false) or not (true).
+func (h *RequestHeader) SetNoDefaultContentType(noDefaultContentType bool) {
+	h.noDefaultContentType = noDefaultContentType
+}
+
 // Reset clears request header.
 func (h *RequestHeader) Reset() {
 	h.disableNormalizing = false
+	h.SetNoDefaultContentType(false)
 	h.resetSkipNormalize()
 }
 
@@ -2273,7 +2280,7 @@ func (h *RequestHeader) AppendBytes(dst []byte) []byte {
 	}
 
 	contentType := h.ContentType()
-	if len(contentType) == 0 && !h.ignoreBody() {
+	if !h.noDefaultContentType && len(contentType) == 0 && !h.ignoreBody() {
 		contentType = strDefaultContentType
 	}
 	if len(contentType) > 0 {

header_test.go

@@ -1381,6 +1381,33 @@ func TestRequestContentTypeDefaultNotEmpty(t *testing.T) {
 	}
 }
 
+func TestRequestContentTypeNoDefault(t *testing.T) {
+	t.Parallel()
+
+	var h RequestHeader
+	h.SetMethod(MethodDelete)
+	h.SetNoDefaultContentType(true)
+
+	w := &bytes.Buffer{}
+	bw := bufio.NewWriter(w)
+	if err := h.Write(bw); err != nil {
+		t.Fatalf("Unexpected error: %s", err)
+	}
+	if err := bw.Flush(); err != nil {
+		t.Fatalf("Unexpected error: %s", err)
+	}
+
+	var h1 RequestHeader
+	br := bufio.NewReader(w)
+	if err := h1.Read(br); err != nil {
+		t.Fatalf("Unexpected error: %s", err)
+	}
+
+	if string(h1.contentType) != "" {
+		t.Fatalf("unexpected Content-Type %q. Expecting %q", h1.contentType, "")
+	}
+}
+
 func TestResponseDateNoDefaultNotEmpty(t *testing.T) {
 	t.Parallel()