Rails 4 skips cache in Rails.cache.fetch

Question

My code is:

def my_method(path)
    Rails.cache.fetch(path, expires_in: 10.minutes, race_condition_ttl: 10) do
        # Calls Net::HTTP.get_response URI.parse path
        response = My::api.get path

        if response.status == 200
            JSON.parse response.body
        else
            nil # Here I need to prevent cache
        end
    end
end

I will not cache on return nil, but it does. How to prevent caching in this case?

Answer 1

One of the not very elegant ways is to raise the erros.

def my_method(path)
  Rails.cache.fetch(path, expires_in: 10.minutes, race_condition_ttl: 10) do
    # Calls Net::HTTP.get_response URI.parse path
    response = My::api.get path

    raise MyCachePreventingError unless response.status == 200

    JSON.parse response.body
  end
rescue MyCachePreventingError
  nil
end

If anyone has a better way I would like to know

Answer 2

Another alternative ...

def my_method(path)
    out = Rails.cache.fetch(path, expires_in: 10.minutes, race_condition_ttl: 10) do
        # Calls Net::HTTP.get_response URI.parse path
        response = My::api.get path

        if response.status == 200
            JSON.parse response.body
        else
            nil # Here I need to prevent cache
        end
    end
    Rails.cache.delete(path) if out.nil?
end