Trying to convert a String to Array before saving to database Rails

Question

So I'm trying to convert a string that I get from a hidden_field to an array before I save it to the database and I'm having no luck. My Active record datatype is:

add_column :contractors, :regions, :text, array: true

My model looks like this

class Contractor < ActiveRecord::Base
  before_validation :make_array

private
    def make_array
        self.regions = self.regions.split(',')
    end
end

and I'm getting the value from a hidden field

<%= f.hidden_field :regions, value: "1,2,3" %>

It seems if I have array: true on database column self.regions is an empty array when the callback runs. If I remove array:true the string is converted to an array with the callback but it won't save to the database (can't cast Array to text). I've tried adding serialize: :regions but I get this error:

ERROR:  array value must start with "{" or dimension information.

I've also tried sending an array from the hidden field with no luck.

Any ideas what I am doing wrong?

Ahmad Sherif · Accepted Answer · 2014-09-13 22:35:57Z

1

Rails (or ActiveRecord) is trying to cast the value assigned to regions (from a controller perhaps) to an array, which results in an empty array given the input. A quick-n-dirty solution is to do the split before assigning the value, like from a controller. Another one is to use an attr_accessor to store the region ids, then use its value in your model callback, like this

# the model
class Contractor < ActiveRecord::Base
   attr_accessor :region_ids # Rails 4? whitelist it in the controller. Rails 3? Whitelist it here using attr_accessible
   # ... the rest
   def make_array
     self.regions = region_ids.split(',')
   end
end

// the view
<%= f.hidden_field :region_ids, value: "1,2,3" %>

answered Sep 13, 2014 at 22:35

Ahmad Sherif

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1 Comment

Bw00d Over a year ago

Thanks for the suggestion. Sounds like having my regions be objects is smarter way to go, and I may eventually do that. I just wanted to see if I could just turn a string from an input field into an array.

The Lazy Log · Accepted Answer · 2014-09-14 03:33:25Z

0

I would suggest using serialize option in this case so that you can easily convert a string into array without worrying too much about other things. You can read more here: http://thelazylog.com/posts/using-serialize-option-in-ruby-on-rails

answered Sep 14, 2014 at 3:33

The Lazy Log

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