module ActiveRecord::Scoping::Default::ClassMethods

Public Instance Methods

unscoped() { || ... } click to toggle source

Returns a scope for the model without the previously set scopes.

class Post < ActiveRecord::Base
  def self.default_scope
    where(published: true)
  end
end

Post.all                                  # Fires "SELECT * FROM posts WHERE published = true"
Post.unscoped.all                         # Fires "SELECT * FROM posts"
Post.where(published: false).unscoped.all # Fires "SELECT * FROM posts"

This method also accepts a block. All queries inside the block will not use the previously set scopes.

Post.unscoped {
  Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
}
# File lib/active_record/scoping/default.rb, line 33
def unscoped
  block_given? ? relation.scoping { yield } : relation
end

Private Instance Methods

build_default_scope(relation = relation()) click to toggle source
# File lib/active_record/scoping/default.rb, line 102
def build_default_scope(relation = relation())
  return if abstract_class?

  if default_scope_override.nil?
    self.default_scope_override = !Base.is_a?(method(:default_scope).owner)
  end

  if default_scope_override
    # The user has defined their own default scope method, so call that
    evaluate_default_scope do
      relation.scoping { default_scope }
    end
  elsif default_scopes.any?
    evaluate_default_scope do
      default_scopes.inject(relation) do |default_scope, scope|
        scope = scope.respond_to?(:to_proc) ? scope : scope.method(:call)
        default_scope.instance_exec(&scope) || default_scope
      end
    end
  end
end
default_scope(scope = nil, &block) click to toggle source

Use this macro in your model to set a default scope for all operations on the model.

class Article < ActiveRecord::Base
  default_scope { where(published: true) }
end

Article.all # => SELECT * FROM articles WHERE published = true

The default_scope is also applied while creating/building a record. It is not applied while updating a record.

Article.new.published    # => true
Article.create.published # => true

(You can also pass any object which responds to call to the default_scope macro, and it will be called when building the default scope.)

If you use multiple default_scope declarations in your model then they will be merged together:

class Article < ActiveRecord::Base
  default_scope { where(published: true) }
  default_scope { where(rating: 'G') }
end

Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'

This is also the case with inheritance and module includes where the parent or module defines a default_scope and the child or including class defines a second one.

If you need to do more complex things with a default scope, you can alternatively define it as a class method:

class Article < ActiveRecord::Base
  def self.default_scope
    # Should return a scope, you can call 'super' here etc.
  end
end
# File lib/active_record/scoping/default.rb, line 88
def default_scope(scope = nil, &block) # :doc:
  scope = block if block_given?

  if scope.is_a?(Relation) || !scope.respond_to?(:call)
    raise ArgumentError,
      "Support for calling #default_scope without a block is removed. For example instead " \
      "of `default_scope where(color: 'red')`, please use " \
      "`default_scope { where(color: 'red') }`. (Alternatively you can just redefine " \
      "self.default_scope.)"
  end

  self.default_scopes += [scope]
end
evaluate_default_scope() { || ... } click to toggle source

The ignore_default_scope flag is used to prevent an infinite recursion situation where a default scope references a scope which has a default scope which references a scope…

# File lib/active_record/scoping/default.rb, line 135
def evaluate_default_scope
  return if ignore_default_scope?

  begin
    self.ignore_default_scope = true
    yield
  ensure
    self.ignore_default_scope = false
  end
end
ignore_default_scope=(ignore) click to toggle source
# File lib/active_record/scoping/default.rb, line 128
def ignore_default_scope=(ignore)
  ScopeRegistry.set_value_for(:ignore_default_scope, base_class, ignore)
end
ignore_default_scope?() click to toggle source
# File lib/active_record/scoping/default.rb, line 124
def ignore_default_scope?
  ScopeRegistry.value_for(:ignore_default_scope, base_class)
end