module ActiveRecord::Scoping::Default::ClassMethods

Public Instance Methods

default_scopes?(all_queries: false) click to toggle source

Checks if the model has any default scopes. If all_queries is set to true, the method will check if there are any default_scopes for the model where all_queries is true.

# File lib/active_record/scoping/default.rb, line 62
def default_scopes?(all_queries: false)
  if all_queries
    self.default_scopes.any?(&:all_queries)
  else
    self.default_scopes.any?
  end
end
unscoped(&block) click to toggle source

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

class Post < ActiveRecord::Base
  belongs_to :user

  def self.default_scope
    where(published: true)
  end
end

class User < ActiveRecord::Base
  has_many :posts
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"
User.find(1).posts                        # Fires "SELECT * FROM posts WHERE published = true AND posts.user_id = 1"
User.find(1).posts.unscoped               # 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 50
def unscoped(&block)
  block_given? ? relation.scoping(&block) : relation
end

Private Instance Methods

build_default_scope(relation = relation(), all_queries: nil) click to toggle source
# File lib/active_record/scoping/default.rb, line 145
def build_default_scope(relation = relation(), all_queries: nil)
  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 |combined_scope, scope_obj|
        if execute_scope?(all_queries, scope_obj)
          scope = scope_obj.scope.respond_to?(:to_proc) ? scope_obj.scope : scope_obj.scope.method(:call)

          combined_scope.instance_exec(&scope) || combined_scope
        else
          combined_scope
        end
      end
    end
  end
end
default_scope(scope = nil, all_queries: 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 or deleting a record.

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

To apply a default_scope when updating or deleting a record, add all_queries: true:

class Article < ActiveRecord::Base
  default_scope -> { where(blog_id: 1) }, all_queries: true
end

Applying a default scope to all queries will ensure that records are always queried by the additional conditions. Note that only where clauses apply, as it does not make sense to add order to queries that return a single object by primary key.

Article.find(1).destroy
# DELETE ... FROM `articles` where ID = 1 AND blog_id = 1;

(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 129
def default_scope(scope = nil, all_queries: 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

  default_scope = DefaultScope.new(scope, all_queries)

  self.default_scopes += [default_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 192
def evaluate_default_scope
  return if ignore_default_scope?

  begin
    self.ignore_default_scope = true
    yield
  ensure
    self.ignore_default_scope = false
  end
end
execute_scope?(all_queries, default_scope_obj) click to toggle source

If all_queries is nil, only execute on select and insert queries.

If all_queries is true, check if the default_scope object has all_queries set, then execute on all queries; select, insert, update, delete, and reload.

# File lib/active_record/scoping/default.rb, line 177
def execute_scope?(all_queries, default_scope_obj)
  all_queries.nil? || all_queries && default_scope_obj.all_queries
end
ignore_default_scope=(ignore) click to toggle source
# File lib/active_record/scoping/default.rb, line 185
def ignore_default_scope=(ignore)
  ScopeRegistry.set_ignore_default_scope(base_class, ignore)
end
ignore_default_scope?() click to toggle source
# File lib/active_record/scoping/default.rb, line 181
def ignore_default_scope?
  ScopeRegistry.ignore_default_scope(base_class)
end