scope determined by model function call

rubyonrails-talk
1

Hi All,

I can work around this if it isn't possible, but I am looking to create a scope for a model which returns records based on the result of a model function.

Essentially, I have the following:

class contract   has_many contract_statuses

  def current_status(date)     ....   end end

class contract_status   belongs_to :contract   belongs_to :status end

class status   has_many :contract_statuses end

The contract_statuses are there to track the status of a contract over time with the latest being the current status for a particular contract. A 'status' simply has a 'name' field.

In my contract model, i have a current_status function which returns the contract_status record that was relevant as a particular time, given a date parameter.

The scope I would like would be something like contracts.active, where active relates to the name of the current status. Ideally, I would like to get the status through the current_status method of the contract, but I've not been able to find a way to do this in a scope.....

Is this possible?

2

Don't suppose anyone has any thoughts regarding this?

Thanks

Paul

3

I probably wouldn’t go as far as you have in breaking status out into a separate model. I’d keep it as an attribute of contract and use ActiveModel::Dirty along with an ActiveRecord after_save callback to handle updates into a contract_status_changes table.

Alternately, you could use something like AASM to implement a finite state machine and add rows to the history table using events / transitions.