caching_method_missing_responses

🧠 Caching Dynamic Method Results Safely

For expensive dynamic lookups, implement a cache inside method_missing to memoize results. Invalidate or expire entries carefully to avoid stale data. This pattern works well for on‑the‑fly computation of attributes from remote services or large data sources.

class RemoteAttributeFetcher
  def initialize(client)
    @client = client
    @cache  = {}
  end

  def method_missing(name, *_args)
    return super unless name.to_s.start_with?('fetch_')

    @cache[name] ||= begin
      attribute = name.to_s.sub('fetch_', '')
      @client.get(attribute)  # potentially slow network call
    end
  end

  def respond_to_missing?(name, include_private = false)
    name.to_s.start_with?('fetch_') || super
  end

  def clear_cache(method_name = nil)
    if method_name
      @cache.delete(method_name)
    else
      @cache.clear
    end
  end
end

fetcher = RemoteAttributeFetcher.new(api_client)
fetcher.fetch_price   # cached on first call
fetcher.clear_cache(:fetch_price)
fetcher.fetch_price   # refetched from service