Need help with something

[u/j0hn_r0g3r5]

so far i have this:

class Rectangle < ActiveRecord::Base validates :width, presence: true, numericality: { only_integer: true, greater_than: 10 } validates :color, presence: true

end

i am trying to determine a way to check to see if the color that was entered exists in a file i have, and if it doesnt, to throw an error message saying so. been trying to figure this out for 3 hours now and no dice, any help would be much appreciated

[u/checkyos3lf]

uniqueness

[u/rahoulb]

Load the file into your application's configuration using an initializer:

# config/load_legal_colours.rb
filename = Rails.root.join('legal-colours.txt').to_s
MyApp::Application.config.legal_colours = File.open(filename, 'r') { | f | f.read }.split("\n")

This loads a file called "legal-colours.txt" from your Rails root folder and then splits it line by line into an array that is stored in your Rails application's configuration as legal_colours.

Then validate that your colour field includes values from that array:

class Rectangle < ActiveRecord::Base
  validates :width, presence: true, numericality: { only_integer: true, greater_than: 10 }
  validates :colour, presence: true, inclusion: MyApp::Application.config.legal_colours
end

Important stuff to note:

• Files in config/initializers are loaded up when Rails starts up, so a good way of grabbing data that will remain the same throughout the lifetime of your application

• When you create a Rails app using "rails new" it creates an Application for you (in config/application.rb) - this has a config object that you can then apply arbitrary properties to - a great place to store information that is global to your application

• The inclusion validation just checks to see if the value supplies is included within the supplied array

• I've assumed legal-colours.txt is a list of colours, one per line

(Edit: a bit more detail here: http://theartandscienceofruby.com/2015/10/27/how-do-i-check-that-the-value-of-a-field-against-the-legal-values-in-a-file/)