diff --git a/lib/pulsar/client/transport/standard.py b/lib/pulsar/client/transport/standard.py
index 999ecce5af9..9a5c46372e4 100644
--- a/lib/pulsar/client/transport/standard.py
+++ b/lib/pulsar/client/transport/standard.py
@@ -24,11 +24,13 @@ class Urllib2Transport(object):
         input = None
         try:
             if input_path:
-                if getsize(input_path):
+                size = getsize(input_path)
+                if size:
                     input = open(input_path, 'rb')
                     data = mmap.mmap(input.fileno(), 0, access=mmap.ACCESS_READ)
                 else:
                     data = b""
+                request.add_header('Content-Length', str(size))
             response = self._url_open(request, data)
         finally:
             if input: