/ Ruby on Rails
/
method

validates_each

validates_each(*attr_names, &block)
public

Validates each attribute against a block.

class Person
  include ActiveModel::Validations

  attr_accessor :first_name, :last_name

  validates_each :first_name, :last_name, allow_blank: true do |record, attr, value|
    record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
  end
end

Options:

  • :on - Specifies the contexts where this validation is active. Runs in all validation contexts by default nil. You can pass a symbol or an array of symbols. (e.g. on: :create or on: :custom_validation_context or on: [:create, :custom_validation_context])

  • :allow_nil - Skip validation if attribute is nil.

  • :allow_blank - Skip validation if attribute is blank.

  • :if - Specifies a method, proc or string to call to determine if the validation should occur (e.g. if: :allow_validation, or if: Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.

  • :unless - Specifies a method, proc or string to call to determine if the validation should not occur (e.g. unless: :skip_validation, or unless: Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.

2Notes

Re: Validate an optional URL field

w_piekutowski · Aug 8, 20092 thanks

Actually it's easier to use validates_format_of for this task. Please refer to the comments under the doc.

Validate an optional URL field

Mange · Feb 23, 2009

Let's say that you have an optional URL field to one of your models and you want to validate the URL. You can accomplish this by using the URI library:

require 'uri' # Put this at the beginning of your model file

validates_each :url, :allow_blank => true do |record, field, value|
begin
  valid = (URI.parse(value).scheme =~ /https?/)
rescue URI::InvalidURIError
  valid = false
end
record.errors.add field, "not a valid url" unless valid
end

If you want to add even more testing in there, just go ahead. For now, we just check that the link is to a HTTP resource, but you might have other requirements. This will allow stuff like "http://example" since "example" might be a valid intranet domain. If you want to check for a TLD in there, you can do so with a simple regexp.

For more information about the URI library, check out http://apidock.com/ruby/URI/