Fixes #1517

proxy/raw_websocket.py

@@ -225,20 +225,21 @@ class RawWebSocket:
         return None
 
     async def close(self):
-        if self._closed:
-            return
-        self._closed = True
         try:
-            self.writer.write(
-                self._build_frame(self.OP_CLOSE, b'', mask=True))
-            await self.writer.drain()
-        except Exception:
-            pass
-        try:
-            self.writer.close()
-            await self.writer.wait_closed()
-        except Exception:
-            pass
+            if not self._closed:
+                self._closed = True
+                try:
+                    self.writer.write(
+                        self._build_frame(self.OP_CLOSE, b'', mask=True))
+                    await self.writer.drain()
+                except Exception:
+                    pass
+        finally:
+            try:
+                self.writer.close()
+                await self.writer.wait_closed()
+            except Exception:
+                pass
 
     _WS_CLOSE_REASONS = {
         1000: 'normal', 1001: 'going_away', 1002: 'protocol_error',