OnlyCat Ruby API client proof-of-concept.

only_cat_api_example.rb

# OnlyCat API Ruby proof-of-concept.
# By Henrik Nyh <https://henrik.nyh.se> 2025-03-16 under the MIT License.
#
# Based on https://community.home-assistant.io/t/home-assistant-integration-for-onlycat-catflap/814906.

require "bundler/inline"
require "json"

gemfile do
  source "https://rubygems.org"
  gem "websocket-eventmachine-client"
end

GATEWAY_URI = "wss://gateway.onlycat.com/socket.io/?platform=script&device=ruby-test-script&EIO=4&transport=websocket"
TOKEN_PATH = "~/.onlycat_token"

begin
  TOKEN = File.read(File.expand_path(TOKEN_PATH)).chop
rescue Errno::ENOENT
  abort "Error: Find your OnlyCat 'Device Token' on the Account tab of the app, and put it in `#{TOKEN_PATH}`."
end

EM.run do
  ws = WebSocket::EventMachine::Client.connect(uri: GATEWAY_URI)

  ws_send = ->(number, data = nil) {
    msg = "#{number}#{data&.to_json}"
    puts "-> #{msg}"
    ws.send(msg)
  }

  stop = ->(_) {
    puts "Terminating connection."
    EventMachine.stop
  }
  trap("TERM", &stop)
  trap("INT", &stop)

  ws.onopen do
    puts "Connected."
  end

  ws.onmessage do |msg, type|
    puts "<- #{msg}"

    case msg
    when /\A0\D/
      puts "(time to auth)"
      ws_send.(40, token: TOKEN)
    when /\A2\z/
      puts "(ping)"
      ws_send.(3)
      puts "(pong)"
    end
  end

  ws.onerror do |error|
    puts "WS error: #{error}"
  end

  ws.onclose do |code, reason|
    puts "Disconnected. Status code: #{code}; reason: #{reason.inspect}"
  end

  EventMachine.add_timer 5, -> {
    puts "Getting devices."
    ws_send.(420, [ "getDevices", { subscribe: false } ])
  }
end