From 26746df1cf8669547b8a2cf3e3cea837a06a4a58 Mon Sep 17 00:00:00 2001
From: David Gauchard <gauchard@laas.fr>
Date: Wed, 15 Dec 2021 13:43:37 +0100
Subject: [PATCH] httpClient: prevent empty user-agent in header

---
 libraries/ESP8266HTTPClient/src/ESP8266HTTPClient.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libraries/ESP8266HTTPClient/src/ESP8266HTTPClient.cpp b/libraries/ESP8266HTTPClient/src/ESP8266HTTPClient.cpp
index 7c52ed8486..2987e2601d 100644
--- a/libraries/ESP8266HTTPClient/src/ESP8266HTTPClient.cpp
+++ b/libraries/ESP8266HTTPClient/src/ESP8266HTTPClient.cpp
@@ -929,8 +929,10 @@ bool HTTPClient::sendHeader(const char * type)
         header += ':';
         header += String(_port);
     }
-    header += F("\r\nUser-Agent: ");
-    header += _userAgent;
+    if (_userAgent.length()) {
+        header += F("\r\nUser-Agent: ");
+        header += _userAgent;
+    }
 
     if (!_useHTTP10) {
         header += F("\r\nAccept-Encoding: identity;q=1,chunked;q=0.1,*;q=0");