fixes #245

cheroot/makefile.py

@@ -36,13 +36,22 @@ def write(self, b):
             self._flush_unlocked()
             return len(b)
 
+    def _safe_call(self, is_reader, call, *args, **kwargs):
+        """Call the supplied callable with retries, as needed.
+
+        Method to be overridden in subclasses/mix-ins.
+        """
+        return call(*args, **kwargs)
+
     def _flush_unlocked(self):
         self._checkClosed('flush of closed file')
         while self._write_buf:
             try:
                 # ssl sockets only except 'bytes', not bytearrays
                 # so perhaps we should conditionally wrap this for perf?
-                n = self.raw.write(bytes(self._write_buf))
+                n = self._safe_call(
+                    False, self.raw.write, bytes(self._write_buf),
+                )
             except io.BlockingIOError as e:
                 n = e.characters_written
             del self._write_buf[:n]

cheroot/ssl/pyopenssl.py

@@ -150,14 +150,24 @@ def readline(self, size=-1):
             size,
         )
 
-    def sendall(self, *args, **kwargs):
-        """Send whole message to the socket."""
+    def read(self, *args, **kwargs):
+        """Read from the wrapped socket, with retry."""
         return self._safe_call(
-            False,
-            super(SSLFileobjectMixin, self).sendall,
+            True,
+            super(SSLFileobjectMixin, self).read,
             *args, **kwargs
         )
 
+    def sendall(self, *args, **kwargs):
+        """Send whole message to the socket. Unsupported, do not use."""
+        # Not supported due to https://github.com/pyca/pyopenssl/issues/176.
+        # Until that bug is fixed, sendall() may throw SSL.WantWriteError, but
+        # there is no correct way to retry the call because we don't know how
+        # many bytes were already transmitted. We could work around this by
+        # reimplementing sendall() using send(), but we don't actually use
+        # sendall() anywhere.
+        raise NotImplementedError('sendall() is unsupported by pyOpenSSL')
+
     def send(self, *args, **kwargs):
         """Send some part of message to the socket."""
         return self._safe_call(