Question

I have a class I’ve extended from ActiveRecord::Base…

class Profile < ActiveRecord::Base

and I collect the records from it like so…

records = @profile.all

which works fine, but it doesn’t seem that I can successfully Update the attributes. I don’t want to save them back to the database, just modify them before I export them as JSON. My question is, why can’t I update these? I’m doing the following (converting date formats before exporting):

        records.collect! { |record|
        unless record.term_start_date.nil?
            record.term_start_date = Date.parse(record.term_start_date.to_s).strftime('%Y,%m,%d')
        end

        unless record.term_end_date.nil? 
            record.term_end_date = Date.parse(record.term_end_date.to_s).strftime('%Y,%m,%d') 
        end

        record
    }

At first I had just been doing this in a do each loop, but tried collect! to see if it would fix things, but no difference. What am I missing?

P.S. – I tried this in irb on one record and got the same results.

Answer 1

I suggest a different way to solve the problem, that keeps the logic encapsulated in the class itself.

Override the as_json instance method in your Profile class.

def as_json(options={})
  attrs = super(options)

  unless attrs['term_start_date'].nil?
    attrs['term_start_date'] = Date.parse(attrs['term_start_date'].to_s).strftime('%Y,%m,%d')
  end

  unless attrs['term_end_date'].nil? 
    attrs['term_end_date'] = Date.parse(attrs['term_end_date'].to_s).strftime('%Y,%m,%d') 
  end

  attrs
end

Now when you render the records to json, they’ll automatically use this logic to generate the intermediate hash. You also don’t run the risk of accidentally saving the formatted dates to the database.

You can also set up your own custom option name in the case that you don’t want the formatting logic.

This blog post explains in more detail.