Unable to close websocket from the on_message handler

[AlexandriaOL]

Description

I am unable to close a socket from the message handler

Steps to Reproduce

require "kemal"

ws "/" do |sock, context|
  sock.on_message do |message|
    puts message
    sock.close HTTP::WebSocket::CloseCode::NormalClosure
  end
  
  sock.on_close do
    puts "Waah"
  end
end

Kemal.run

Expected behavior:

It should close the websocket after a message is recieved

Actual behavior:

The websocket stays open and can continue sending messages

Reproduces how often:

continually

Versions

aster@hephaestus:redacted$ crystal --version
Crystal 1.2.1 [4e6c0f26e] (2021-10-21)

LLVM: 10.0.0
Default target: x86_64-unknown-linux-gnu

[a-alhusaini]

Is this actually an issue in Kemal or Crystal's HTTP::WebSocketHandler?

[a-alhusaini]

on_close is only triggerred if a websocket connection is closed from the othe side. Since your server is the one that closed it. The on_close handler will never get triggerred.

If the client were to close the connection. on_close would be triggerred on the server side.

[straight-shoota]

To clarify: on_close listens for a WebSocket close event. This is a specific event that must be explicitly sent from the other end. It's not implicit when for example the underlying connection closes.