CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3validationlambdaproc
Dmitri
Dmitri

Reputation: 2467

Rails validation variable proc

:inclusion => {:in => r = (1..15), :min => r.first, :max => r.last}

This is working code I have. The thing I wanted to make dynamic is the "15" part, e.g

:inclusion => {:in => r = (1..Vehicle.max_passengers), :min => r.first, :max => r.last}

I have defined the following class method:

def self.max_passengers
   15
end

Of course it didn't work. I've tried using Procs and lambdas, but It didn't work properly for me. :( Can someone help me with this one - is it possible ?

Upvotes: 0

Views: 3055

Answers (3)

Matt
Matt

Reputation: 5398

Try this:

inclusion: { in: proc { 1..Vehicle.max_passengers } }

Upvotes: 0

Amir
Amir

Reputation: 1872

You're looking for a custom validation method:

ActiveRecord::Base.class_eval do
  def self.validates_max_passenger(attr_name, r)
    validates attr_name, :inclusion => { :in => r, :min => r.first, :max => r.last } }
  end
end

# later in your class of choice:      
validates_max_passenger :passengers, 1..5

Or, you can try the following with lambda

def self.max_passengers
   1..15
end  


validates :attrib, :inclusion => {:in => lambda { |obj| ClassName.max_passengers } }

Note that you won't need the min/max if you're using :in on range.

Upvotes: 3

Varinder Singh
Varinder Singh

Reputation: 1590

Check if validates_with is of any help.This helper passes the record to a separate class for validation in which you can make your validation criteria dynamic i.e by reading some config or so on. More info on validates_with is available at ruby on rails guide

class Person < ActiveRecord::Base
  validates_with GoodnessValidator
end

class GoodnessValidator < ActiveModel::Validator
  def validate(record)
     # implement your dynamic criteria here                 
  end
end

Upvotes: 0

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