slack-sni-problem

require "net/http"
require "websocket"

store = OpenSSL::X509::Store.new
store.set_default_paths

ctx = OpenSSL::SSL::SSLContext.new(:TLSv1_2_client)
ctx.set_params(verify_mode: OpenSSL::SSL::VERIFY_PEER)
ctx.cert_store = store
sock = OpenSSL::SSL::SSLSocket.open(
  'wss-backup.slack.com',
  443,
  context: ctx
)
########
######## Apparently setting this hostname here is super important, as it's a hint for SNI.
######## In the output of this script look for 404 vs 101 depending on uncommenitng this or commenting it.
######## Also, I'm using Ruby 2.7.4.
########
sock.hostname = 'wss-primary.slack.com'
sock.sync = true
puts sock.state
sock.connect
handshake = WebSocket::Handshake::Client.new(
  url: 'wss://wss-backup.slack.com/websocket/r8VGtIZfIbt0u98IKuhBgs2_jpbkns1ySzL14za4A8J0Y9ZdBIZgDHtC6UNS5HjkzQKOLBgwJNdx4xBFyrbm8-errf2_mnLz7u674L8s9He9PlQhnlyPQ2UJWz2G1uAoTZcM4y5hudtSuG36/2'
)
handshake_str = handshake.to_s
sock.write(handshake_str)
loop do
  got = sock.gets
  puts got
  handshake << got
  break if handshake.finished?
end
puts handshake.inspect