"WebSocket protocol error: httparse error: invalid token" when connect from ngrok tcp tunnel.

[Atlinx]

When I tried using an ngrok tcp tunnel to point towards a tokio-tungstenite websocket server on my localhost, I get an "httparse error: invalid token" error. Does anyone know why this is happening?

[daniel-abramov]

Sounds like an invalid header line or something. This error originates from the httparse dependency that parses the HTTP. And here is the error, i.e. I think a simple example with httparse would fail for the same reason, so maybe you could check what you're getting from the server that makes it fail.

[Atlinx]

I've made a simple tcp server to listen for websocket connections, but the initial message sent to the server seems to be garbled.

Here's a request I got on this test TCP server via ngrok:

Opened connection from 127.0.0.1:64160
  Got string: ▬♥☺☻.☺☻*♥♥u�h��&�►�2�v51�↨��d:�♣0���◄ 0��x�R��Y�x� �↓/(�}S;?F'�������� ZZ‼☺‼☻‼♥�+�/�,�0̨̩�‼�¶��/5☺☺ ☺���Di♣♥☻h2↨‼◄0.tcp.ngrok.io#�☺☺-☻☺☺+♠JJ♥♦♥♥

[�7!�ۅ���+↓�W�h↓Х ,?���▼�♣5♥AB��v�A��↔l&↨↑H∟�d�@=m�)�fJ$v̜��FO��qČ�}z��݂�=)S��E����↕�0Ά���→:�↓���?s��G޺�G�W�R�nm[ [r�����:
�F���]0C��'q��d,�'�9����2��7}Q�#�__Q☺◄��o"&�1C�A�����<���f@�♠c��{♣w��Ft
↕►♦♦♦☺♣♣♣♠♠☺↕►
       http/1.1♥☻☻

☻☺J☺

Could this maybe have something to do with connecting with secure websockets (wss://) over ngrok?

[daniel-abramov]

This certainly depends on the configuration of the ngrok. I think without an additional configuration it would indeed expect non-encrypted traffic. So it depends on which endpoints you're exposing.

[Atlinx]

I'm running a tcp tunnel through ngrok without tls (using ngrok tcp 9000, however I have to connect to the tcp endpoint using wss:// because unsecure websockets are not allowed when content is loaded from secure sites. I think if I tried using an http tunnel ngrok should translate the encrypted traffic to unencrypted traffic. But I'll need to pass a header to bypass the browser warning.

[agalakhov]

The "Got string" message looks like TLS encryption. Can it be that the client expects unencrypted HTTP headers while the server sends encrypted ones? In this case you would get a httparse error message just like you actually got. How exactly do you connect?