module ActiveRecord
class PredicateBuilder # :nodoc:
@handlers = []
autoload :RelationHandler, 'active_record/relation/predicate_builder/relation_handler'
autoload :ArrayHandler, 'active_record/relation/predicate_builder/array_handler'
def initialize(klass, table)
@klass = klass
@table = table
end
def resolve_column_aliases(hash)
hash = hash.dup
hash.keys.grep(Symbol) do |key|
if klass.attribute_alias? key
hash[klass.attribute_alias(key)] = hash.delete key
end
end
hash
end
def build_from_hash(attributes)
attributes = convert_dot_notation_to_hash(attributes.stringify_keys)
expand_from_hash(attributes)
end
def expand(column, value)
queries = []
# 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)
if klass && reflection = klass._reflect_on_association(column)
if reflection.polymorphic? && base_class = polymorphic_base_class_from_value(value)
queries << self.class.build(table[reflection.foreign_type], base_class.name)
end
column = reflection.foreign_key
end
queries << self.class.build(table[column], value)
queries
end
def polymorphic_base_class_from_value(value)
case value
when Relation
value.klass.base_class
when Array
val = value.compact.first
val.class.base_class if val.is_a?(Base)
when Base
value.class.base_class
end
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.register_handler(MyCustomDateRange, handler)
def self.register_handler(klass, handler)
@handlers.unshift([klass, handler])
end
register_handler(BasicObject, ->(attribute, value) { attribute.eq(value) })
register_handler(Class, ->(attribute, value) { deprecate_class_handler; attribute.eq(value.name) })
register_handler(Base, ->(attribute, value) { attribute.eq(value.id) })
register_handler(Range, ->(attribute, value) { attribute.between(value) })
register_handler(Relation, RelationHandler.new)
register_handler(Array, ArrayHandler.new)
def self.build(attribute, value)
handler_for(value).call(attribute, value)
end
def self.handler_for(object)
@handlers.detect { |klass, _| klass === object }.last
end
private_class_method :handler_for
def self.deprecate_class_handler
ActiveSupport::Deprecation.warn(<<-MSG.squish)
Passing a class as a value in an Active Record query is deprecated and
will be removed. Pass a string instead.
MSG
end
protected
attr_reader :klass, :table
def expand_from_hash(attributes)
return ["1=0"] if attributes.empty?
attributes.flat_map do |key, value|
if value.is_a?(Hash)
arel_table = Arel::Table.new(key)
association = klass._reflect_on_association(key)
builder = self.class.new(association && association.klass, arel_table)
builder.expand_from_hash(value)
else
expand(key, value)
end
end
end
private
def convert_dot_notation_to_hash(attributes)
dot_notation = attributes.keys.select { |s| s.include?(".") }
dot_notation.each 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
end
end