Problem with ZnWebSocket and closed connections

Davide Varvello varvello at
Thu Feb 20 13:08:43 EST 2020

Hi guys!
I've a problem with websockets, I'm quite a noob on the subject and I'm
doing some tests with them.

I run the echo websocket this way:

ZnServer startDefaultOn: 8000.
ZnServer default delegate: (ZnWebSocketDelegate handler:
ZnWebSocketEchoHandler new).

I tested it with with the chrome extension
that emulates a websocket client. If I point to the url ws://localhost:8000
everyting is fine
I want to test the websocket server via ngrok ( and if I
point the client to the ngrok url (i.e. ws:// that maps
localhost:8000) it happens a connection-closed after a while and I can't
understand the cause, is there a timeout somewhere?

I know that it is something related to Pharo (and not to ngrok) because if I
implement a simple echo websocket served via websocketd
( the connection stays always active even if through

Can you help me please?

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