aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/scoping/default.rb
blob: b35fec792026ac57fcbd62d9e2c00c05d7e40ee5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
require 'active_support/concern'
require 'active_support/deprecation'

module ActiveRecord
  module Scoping
    module Default
      extend ActiveSupport::Concern

      included do
        # Stores the default scope for the class
        class_attribute :default_scopes, instance_writer: false
        self.default_scopes = []
      end

      module ClassMethods
        # Returns a scope for the model without the default_scope.
        #
        #   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"
        #
        # This method also accepts a block. All queries inside the block will
        # not use the default_scope:
        #
        #   Post.unscoped {
        #     Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
        #   }
        #
        # It is recommended that you use the block form of unscoped because
        # chaining unscoped with <tt>scope</tt> does not work. Assuming that
        # <tt>published</tt> is a <tt>scope</tt>, the following two statements
        # are equal: the <tt>default_scope</tt> is applied on both.
        #
        #   Post.unscoped.published
        #   Post.published
        def unscoped
          block_given? ? relation.scoping { yield } : relation
        end

        def before_remove_const #:nodoc:
          self.current_scope = nil
        end

        protected

        # 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 <tt>default_scope</tt> 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 <tt>call</tt> to the <tt>default_scope</tt>
        # macro, and it will be called when building the default scope.)
        #
        # If you use multiple <tt>default_scope</tt> 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 <tt>default_scope</tt> 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
        def default_scope(scope = nil)
          scope = Proc.new if block_given?

          if scope.is_a?(Relation) || !scope.respond_to?(:call)
            ActiveSupport::Deprecation.warn(
              "Calling #default_scope without a block is deprecated. 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 = default_scopes + [scope]
        end

        def build_default_scope #:nodoc:
          if !Base.is_a?(method(:default_scope).owner)
            # The user has defined their own default scope method, so call that
            evaluate_default_scope { default_scope }
          elsif default_scopes.any?
            evaluate_default_scope do
              default_scopes.inject(relation) do |default_scope, scope|
                if !scope.is_a?(Relation) && scope.respond_to?(:call)
                  default_scope.merge(unscoped { scope.call })
                else
                  default_scope.merge(scope)
                end
              end
            end
          end
        end

        def ignore_default_scope? #:nodoc:
          Thread.current["#{self}_ignore_default_scope"]
        end

        def ignore_default_scope=(ignore) #:nodoc:
          Thread.current["#{self}_ignore_default_scope"] = ignore
        end

        # 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...
        def evaluate_default_scope
          return if ignore_default_scope?

          begin
            self.ignore_default_scope = true
            yield
          ensure
            self.ignore_default_scope = false
          end
        end

      end
    end
  end
end