backpressure_throttling

🔄 Implementing Backpressure Control in Channels

Prevent message flooding and protect clients by implementing rate-limiting within your channel. Use a sliding window counter stored in Redis to throttle excessive broadcasts per connection.

# app/channels/application_cable/connection.rb
module ApplicationCable
  class Connection < ActionCable::Connection::Base
    identified_by :current_user, :throttle_key

    def connect
      self.current_user = find_verified_user
      self.throttle_key = "ws:#{current_user.id}:throttle"
    end
  end
end

# app/channels/chat_channel.rb
class ChatChannel < ApplicationCable::Channel
  MAX_RATE = 5  # messages per 10 seconds

  def speak(data)
    count = Redis.current.incr(throttle_key)
    Redis.current.expire(throttle_key, 10) if count == 1
    if count <= MAX_RATE
      ActionCable.server.broadcast('chat', data)
    else
      transmit(error: 'Rate limit exceeded')
    end
  end
end

This backpressure mechanism drops or rejects messages beyond your threshold, ensuring stability under high load.