Adds support for models using compound primary keys

lib/identity_cache/cached/attribute.rb

@@ -19,7 +19,14 @@ def initialize(model, attribute_or_proc, alias_name, key_fields, unique)
  end
 
  def attribute
- @attribute ||= @attribute_proc.call.to_sym
+ @attribute ||= begin
+ res = @attribute_proc.call
+ if res.is_a?(Array)
+ res.map(&:to_sym)
+ else
+ res.to_sym
+ end
+ end
  end
 
  def fetch(db_key)
@@ -59,7 +66,11 @@ def cache_key(index_key)
  def load_one_from_db(key)
  query = model.reorder(nil).where(load_from_db_where_conditions(key))
  query = query.limit(1) if unique
- results = query.pluck(attribute)
+ results = if attribute.is_a?(Array)
+ query.pluck(*attribute)
+ else
+ query.pluck(attribute)
+ end
  unique ? results.first : results
  end
 
@@ -138,10 +149,15 @@ def field_types
 
  def cache_key_prefix
  @cache_key_prefix ||= begin
+ attribute_key_prefix = if attribute.is_a?(Array)
+ attribute.join("/")
+ else
+ attribute.to_s
+ end
  unique_indicator = unique ? "" : "s"
  "attr#{unique_indicator}" \
  ":#{model.base_class.name}" \
- ":#{attribute}" \
+ ":#{attribute_key_prefix}" \
  ":#{key_fields.join("/")}:"
  end
  end

test/custom_primary_keys_test.rb

@@ -10,11 +10,23 @@ def setup
  @parent_record = CustomParentRecord.create!(parent_primary_key: 1)
  @child_record_1 = CustomChildRecord.create!(custom_parent_record: @parent_record, child_primary_key: 1)
  @child_record_2 = CustomChildRecord.create!(custom_parent_record: @parent_record, child_primary_key: 2)
+
+ CompositePrimaryKeyRecord.cache_has_many(:custom_child_records)
+ CPKReference.cache_belongs_to(:composite_primary_key_record)
+ @composite_record = CompositePrimaryKeyRecord.create!(key_part_one: 1, key_part_two: 2)
+ @cpk_reference = CPKReference.create!(composite_primary_key_record: @composite_record)
  end
 
  def test_fetch_parent
  assert_nothing_raised do
  CustomParentRecord.fetch(@parent_record.parent_primary_key)
  end
  end
+
+ def test_fetch_composite_primary_key_record
+ assert_nothing_raised do
+ cpk_record = CompositePrimaryKeyRecord.fetch([@composite_record.key_part_one, @composite_record.key_part_two])
+ refute_nil cpk_record
+ end
+ end
 end

test/helpers/active_record_objects.rb

@@ -50,6 +50,8 @@ def teardown_models
  Object.send(:remove_const, "Deeply")
  Object.send(:remove_const, "CustomParentRecord")
  Object.send(:remove_const, "CustomChildRecord")
+ Object.send(:remove_const, "CompositePrimaryKeyRecord")
+ Object.send(:remove_const, "CPKReference")
  IdentityCache.const_get(:ParentModelExpiration).send(:lazy_hooks).clear
  end
 end

test/helpers/models.rb

@@ -96,3 +96,14 @@ class CustomChildRecord < ActiveRecord::Base
  belongs_to :custom_parent_record, foreign_key: :parent_id
  self.primary_key = "child_primary_key"
 end
+
+class CompositePrimaryKeyRecord < ActiveRecord::Base
+ include IdentityCache
+ has_many :cpk_references, foreign_key: [:key_part_one, :key_part_two]
+ self.primary_key = [:key_part_one, :key_part_two]
+end
+
+class CPKReference < ActiveRecord::Base
+ include IdentityCache
+ belongs_to :composite_primary_key_record, foreign_key: [:key_part_one, :key_part_two]
+end