Rails: how to require at least one field not to be blank

问题

I know I can require a field by adding validates_presence_of :field to the model. However, how do I require at least one field to be mandatory, while not requiring any particular field?

thanks in advance

-- Deb

回答1:

You can use:

validate :any_present?

def any_present?
  if %w(field1 field2 field3).all?{|attr| self[attr].blank?}
    errors.add :base, "Error message"
  end
end

EDIT: updated from original answer for Rails 3+ as per comment.

But you have to provide field names manually. You could get all content columns of a model with Model.content_columns.map(&:name), but it will include created_at and updated_at columns too, and that is probably not what you want.

回答2:

Here's a reusable version:

class AnyPresenceValidator < ActiveModel::Validator
  def validate(record)
    unless options[:fields].any?{|attr| record[attr].present?}
      record.errors.add(:base, :blank)
    end
  end
end

You can use it in your model with:

validates_with AnyPresenceValidator, fields: %w(field1 field2 field3)

回答3:

Add a validate method to your model:

def validate
  if field1.blank? and field2.blank? and field3.blank? # ...
    errors.add_to_base("You must fill in at least one field")
  end
end

回答4:

I believe something like the following may work

class MyModel < ActiveRecord::Base
   validate do |my_model|
      my_model.my_validation
   end

   def my_validation      
      errors.add_to_base("Your error message") if self.blank? 
      #or self.attributes.blank? - not sure
   end
end

回答5:

Going further with @Votya's correct answer, here is a way to retrieve all columns besides created_at and updated_at (and optionally, any others you want to throw out):

# Get all column names as an array and reject the ones we don't want
Model.content_columns.map(&:name).reject {|i| i =~ /(created|updated)_at/}

For example:

 1.9.3p327 :012 > Client.content_columns.map(&:name).reject {|i| i =~ /(created|updated)_at/}
 => ["primary_email", "name"]

来源：https://stackoverflow.com/questions/2823628/rails-how-to-require-at-least-one-field-not-to-be-blank

标签

ruby-on-rails

validation

models