Module: Recliner::Validations::ClassMethods

Defined in:
lib/recliner/validations/uniqueness.rb

Instance Method Summary collapse

Instance Method Details

#validates_uniqueness_of(*attr_names) ⇒ Object

Validates whether the value of the specified attributes are unique across the system. Useful for making sure that only one user can be named “davidhh”.

class Person < Recliner::Document
  validates_uniqueness_of :user_name, :scope => :account_id
end

It can also validate whether the value of the specified attributes are unique based on multiple scope parameters. For example, making sure that a teacher can only be on the schedule once per semester for a particular class.

class TeacherSchedule < Recliner::Document
  validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
end

When the document is created, a check is performed to make sure that no document exists in the database with the given value for the specified attribute (that maps to a property). When the document is updated, the same check is made but disregarding the document itself.

Configuration options:

  • :message - Specifies a custom error message (default is: “has already been taken”).

  • :scope - One or more properties by which to limit the scope of the uniqueness constraint.

  • :allow_nil - If set to true, skips this validation if the attribute is nil (default is false).

  • :allow_blank - If set to true, skips this validation if the attribute is blank (default is false).

  • :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.



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# File 'lib/recliner/validations/uniqueness.rb', line 32

def validates_uniqueness_of(*attr_names)
  configuration = attr_names.extract_options!

  keys = {}

  attr_names.each do |attr_name|
    if configuration[:view]
      keys[attr_name] = views[configuration[:view]][:key]
    else
      keys[attr_name] = [attr_name]
      keys[attr_name] += Array(configuration[:scope]) if configuration[:scope]
      view _validates_uniqueness_of_view_name(keys[attr_name]), :key => keys[attr_name], :select => :_id
    end
  end

  validates_each(attr_names, configuration) do |document, attr_name, value|
    view = configuration[:view] ? configuration[:view] : _validates_uniqueness_of_view_name(keys[attr_name])
    
    if keys[attr_name].is_a?(Array)
      values = keys[attr_name].map { |k| document.read_attribute(k).to_couch }
    else
      values = document.read_attribute(keys[attr_name]).to_couch
    end
    
    ids = send(view, values).map { |result| result['_id'] }
    
    unless ids.empty? || ids.all? { |id| id == document.id }
      document.errors.add(attr_name, :taken, :default => configuration[:message], :value => value)
    end
  end
end