# module ActiveModel::SecurePassword::ClassMethods

### Public Instance Methods

has_secure_password(options = {}) click to toggle source

Adds methods to set and authenticate against a BCrypt password. This mechanism requires you to have a `password_digest` attribute.

The following validations are added automatically:

- Password must be present on creation

- Password length should be less than or equal to 72 characters

- Confirmation of password (using a `password_confirmation` attribute)

If password confirmation validation is not needed, simply leave out the value for `password_confirmation` (i.e. don't provide a form field for it). When this attribute has a `nil` value, the validation will not be triggered.

For further customizability, it is possible to suppress the default validations by passing `validations: false` as an argument.

Add bcrypt (~> 3.1.7) to Gemfile to use has_secure_password:

    gem 'bcrypt', '~> 3.1.7'

Example using Active Record (which automatically includes ActiveModel::SecurePassword):

    # Schema: User(name:string, password_digest:string)
    class User < ActiveRecord::Base
      has_secure_password
    end

    user = User.new(name: 'david', password: '', password_confirmation: 'nomatch')
    user.save                                                       # => false, password required
    user.password = 'mUc3m00RsqyRe'
    user.save                                                       # => false, confirmation doesn't match
    user.password_confirmation = 'mUc3m00RsqyRe'
    user.save                                                       # => true
    user.authenticate('notright')                                   # => false
    user.authenticate('mUc3m00RsqyRe')                              # => user
    User.find_by(name: 'david').try(:authenticate, 'notright')      # => false
    User.find_by(name: 'david').try(:authenticate, 'mUc3m00RsqyRe') # => user

    # File lib/active_model/secure_password.rb, line 53
    def has_secure_password(options = {})
      # Load bcrypt gem only when has_secure_password is used.
      # This is to avoid ActiveModel (and by extension the entire framework)
      # being dependent on a binary library.
      begin
        require "bcrypt"
      rescue LoadError
        $stderr.puts "You don't have bcrypt installed in your application. Please add it to your Gemfile and run bundle install"
        raise
      end

      include InstanceMethodsOnActivation

      if options.fetch(:validations, true)
        include ActiveModel::Validations

        # This ensures the model has a password by checking whether the password_digest
        # is present, so that this works with both new and existing records. However,
        # when there is an error, the message is added to the password attribute instead
        # so that the error message will make sense to the end-user.
        validate do |record|
          record.errors.add(:password, :blank) unless record.password_digest.present?
        end

        validates_length_of :password, maximum: ActiveModel::SecurePassword::MAX_PASSWORD_LENGTH_ALLOWED
        validates_confirmation_of :password, allow_blank: true
      end
    end