WebSocket connections fail when NATS server is configured with TLS verification.

[allanbank]

When using a WesSocket URI to connect to the NATS server and the server is configured to verify client TLS connections via the NATS protocol the server sends the tls_required=true flag as part of the initial INFO message.

That results in the WebSocketTransport's connect_tls(...) method getting called with the hostname instead of the full URL. That gets passed to the to the aiohttp library and eventually results in a exception like:

aiohttp.client_exceptions.InvalidURL: localhost

This can be reproduced with the following patch:

diff --git a/tests/utils.py b/tests/utils.py
index 711e6f5..cd00a65 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -477,7 +477,7 @@ class SingleWebSocketTLSServerTestCase(unittest.TestCase):
         )
 
         server = NATSD(
-            port=4222, config_file=get_config_file("conf/ws_tls.conf")
+            port=4222, tls=True, config_file=get_config_file("conf/ws_tls.conf")
         )
         self.server_pool.append(server)
         for natsd in self.server_pool:

The fundamental issue is that for the WebSocket connections the TLS upgrade is not supported and should not be attempted.

I think there are two potential solutions:

1. Update the Client. _process_connect_init(self) to not do the tls_required processing on ws or wss connections.
2. Update the WebSocketTransport to detect the second connect[_tls]() call and ignore it if already connected via TLS or throw an exception if not connected via TLS.

I am partial to the second option and will work on a pull request to implement that but I am happy to be pointed in a different direction.