Skip HTTP inbound PlainHTTP mode

common/protocol/http/sniff.go

@@ -60,6 +60,12 @@ func beginWithHTTPMethod(b []byte) error {
 
 func SniffHTTP(b []byte, c context.Context) (*SniffHeader, error) {
 	content := session.ContentFromContext(c)
+	ShouldSniffAttr := true
+	// If content.Attributes have information, that means it comes from HTTP inbound PlainHTTP mode.
+	// It will set sttributes, so skip it.
+	if len(content.Attributes) != 0 || content == nil {
+		ShouldSniffAttr = false
+	}
 	if err := beginWithHTTPMethod(b); err != nil {
 		return nil, err
 	}
@@ -80,7 +86,7 @@ func SniffHTTP(b []byte, c context.Context) (*SniffHeader, error) {
 		}
 		key := strings.ToLower(string(parts[0]))
 		value := string(bytes.TrimSpace(parts[1]))
-		if content != nil {
+		if ShouldSniffAttr {
 			content.SetAttribute(key, value) // Put header in attribute
 		}
 		if key == "host" {
@@ -95,7 +101,7 @@ func SniffHTTP(b []byte, c context.Context) (*SniffHeader, error) {
 	// Parse request line
 	// Request line is like this
 	// "GET /homo/114514 HTTP/1.1"
-	if len(headers) > 0 && content != nil {
+	if len(headers) > 0 && ShouldSniffAttr {
 		RequestLineParts := bytes.Split(headers[0], []byte{' '})
 		if len(RequestLineParts) == 3 {
 			content.SetAttribute(":method", string(RequestLineParts[0]))