delay sending headers in scgi server when possible

1 files changed, 4 insertions, 3 deletions

diff --git a/wsgitools/scgi.py b/wsgitools/scgi.py
index c12a296..51349a0 100644
--- a/wsgitools/scgi.py
+++ b/wsgitools/scgi.py
@@ -54,8 +54,9 @@ class SCGIConnection(asyncore.dispatcher):
 
     def _wsgi_write(self, data):
         assert self.state >= SCGIConnection.REQ
-        self._try_send_headers()
-        self.outbuff += data
+        if data:
+            self._try_send_headers()
+            self.outbuff += data
 
     def readable(self):
         """asyncore interface"""
@@ -144,9 +145,9 @@ class SCGIConnection(asyncore.dispatcher):
         assert self.state >= SCGIConnection.REQ
         if len(self.outbuff) < self.BLOCK_SIZE:
             for data in self.wsgihandler:
-                self._try_send_headers()
                 self.outbuff += data
                 if len(self.outbuff) >= self.BLOCK_SIZE:
+                    self._try_send_headers()
                     break
             if len(self.outbuff) == 0:
                 if hasattr(self.wsgihandler, "close"):