Customise message for validates_uniqueness_of

I am trying to convert an integer to a DAYNAME in my validation message

validates_uniqueness_of :day, scope: :store, :message => “already has a target for #{Date::DAYNAMES[self.day]}.”

``

This does not seem to work, I cannot access the day value.

The following displays the correct value

validates_uniqueness_of :day, scope: :store, :message => “already has a target for %{value}.”

``

This throws an error:

validates_uniqueness_of :day, scope: :store, :message => “already has a target for #{Date::DAYNAMES[%{value}]}.”

``

Any help would be Amazing!

Using double quotes with #{} will definitely not do what you want; the interpolation will be attempted at class-load time, not when the string is needed.

The value passed to :message is handed off to I18n.translate, so the docs for that may be some help.

It may be easier (and clearer) to just define a custom validation function that does what you want.

–Matt Jones

This is along the lines of what Matt is referring to.

class DayValidator < ActiveRecord::Validator
def validate()
if YOUR_TEST_FOR_INVALIDITY(record.day)
date = Date::DAYNAMES[record.day]
record.errors[:day] << “already has a target #{date}”
end
end
end

class YourClass < ActiveRecord::Base
validates_with DayValidator
end

``