aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/relation/predicate_builder.rb
blob: b59ff912feff232955cdd80bfd7dcad8a8e0395b (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
# frozen_string_literal: true

module ActiveRecord
  class PredicateBuilder # :nodoc:
    delegate :resolve_column_aliases, to: :table

    def initialize(table)
      @table = table
      @handlers = []

      register_handler(BasicObject, BasicObjectHandler.new(self))
      register_handler(Base, BaseHandler.new(self))
      register_handler(Range, RangeHandler.new(self))
      register_handler(Relation, RelationHandler.new)
      register_handler(Array, ArrayHandler.new(self))
      register_handler(Set, ArrayHandler.new(self))
    end

    def build_from_hash(attributes)
      attributes = convert_dot_notation_to_hash(attributes)
      expand_from_hash(attributes)
    end

    def self.references(attributes)
      attributes.map do |key, value|
        if value.is_a?(Hash)
          key
        else
          key = key.to_s
          key.split(".").first if key.include?(".")
        end
      end.compact
    end

    # Define how a class is converted to Arel nodes when passed to +where+.
    # The handler can be any object that responds to +call+, and will be used
    # for any value that +===+ the class given. For example:
    #
    #     MyCustomDateRange = Struct.new(:start, :end)
    #     handler = proc do |column, range|
    #       Arel::Nodes::Between.new(column,
    #         Arel::Nodes::And.new([range.start, range.end])
    #       )
    #     end
    #     ActiveRecord::PredicateBuilder.new("users").register_handler(MyCustomDateRange, handler)
    def register_handler(klass, handler)
      @handlers.unshift([klass, handler])
    end

    def build(attribute, value)
      if table.type(attribute.name).force_equality?(value)
        bind = build_bind_attribute(attribute.name, value)
        attribute.eq(bind)
      else
        handler_for(value).call(attribute, value)
      end
    end

    def build_bind_attribute(column_name, value)
      attr = Relation::QueryAttribute.new(column_name.to_s, value, table.type(column_name))
      Arel::Nodes::BindParam.new(attr)
    end

    protected
      def expand_from_hash(attributes)
        return ["1=0"] if attributes.empty?

        attributes.flat_map do |key, value|
          if value.is_a?(Hash) && !table.has_column?(key)
            associated_predicate_builder(key).expand_from_hash(value)
          elsif table.associated_with?(key)
            # Find the foreign key when using queries such as:
            # Post.where(author: author)
            #
            # For polymorphic relationships, find the foreign key and type:
            # PriceEstimate.where(estimate_of: treasure)
            associated_table = table.associated_table(key)
            if associated_table.polymorphic_association?
              case value.is_a?(Array) ? value.first : value
              when Base, Relation
                value = [value] unless value.is_a?(Array)
                klass = PolymorphicArrayValue
              end
            end

            klass ||= AssociationQueryValue
            queries = klass.new(associated_table, value).queries.map do |query|
              expand_from_hash(query).reduce(&:and)
            end
            queries.reduce(&:or)
          elsif table.aggregated_with?(key)
            mapping = table.reflect_on_aggregation(key).mapping
            queries = Array.wrap(value).map do |object|
              mapping.map do |field_attr, aggregate_attr|
                if mapping.size == 1 && !object.respond_to?(aggregate_attr)
                  build(table.arel_attribute(field_attr), object)
                else
                  build(table.arel_attribute(field_attr), object.send(aggregate_attr))
                end
              end.reduce(&:and)
            end
            queries.reduce(&:or)
          else
            build(table.arel_attribute(key), value)
          end
        end
      end

    private
      attr_reader :table

      def associated_predicate_builder(association_name)
        self.class.new(table.associated_table(association_name))
      end

      def convert_dot_notation_to_hash(attributes)
        dot_notation = attributes.select do |k, v|
          k.include?(".") && !v.is_a?(Hash)
        end

        dot_notation.each_key do |key|
          table_name, column_name = key.split(".")
          value = attributes.delete(key)
          attributes[table_name] ||= {}

          attributes[table_name] = attributes[table_name].merge(column_name => value)
        end

        attributes
      end

      def handler_for(object)
        @handlers.detect { |klass, _| klass === object }.last
      end
  end
end

require "active_record/relation/predicate_builder/array_handler"
require "active_record/relation/predicate_builder/base_handler"
require "active_record/relation/predicate_builder/basic_object_handler"
require "active_record/relation/predicate_builder/range_handler"
require "active_record/relation/predicate_builder/relation_handler"

require "active_record/relation/predicate_builder/association_query_value"
require "active_record/relation/predicate_builder/polymorphic_array_value"