diff --git a/mercurial/hgweb/server.py b/mercurial/hgweb/server.py
--- a/mercurial/hgweb/server.py
+++ b/mercurial/hgweb/server.py
@@ -257,8 +257,10 @@
 
     def setup(self):
         self.connection = self.request
-        self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
-        self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)
+        fo = getattr(socket, '_fileobject',
+                     lambda s, mode, bufsize: s.makefile(mode, bufsize))
+        self.rfile = fo(self.request, r"rb", self.rbufsize)
+        self.wfile = fo(self.request, r"wb", self.wbufsize)
 
 try:
     import threading