Add polymorfic associations

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Change log
 
+## master
+- [PR #61](https://github.com/DmitryTsepelev/store_model/pull/61) Add polymorfic associations ([@HolyWalley]())
+
 ## 0.7.0 (2019-11-19)
 
 - [PR #48](https://github.com/DmitryTsepelev/store_model/pull/46) Support merging errors for ArrayType ([@bostanio]())

lib/active_model/validations/store_model_validator.rb

@@ -21,9 +21,9 @@ def validate_each(record, attribute, value)
         end
 
         case record.type_for_attribute(attribute).type
-        when :json
+        when :json, :polymorphic
           call_json_strategy(attribute, record.errors, value)
-        when :array
+        when :array, :polymorphic_array
           call_array_strategy(attribute, record.errors, value)
         end
       end

lib/store_model.rb

@@ -10,5 +10,10 @@ class << self
     def config
       @config ||= Configuration.new
     end
+
+    # @return instance [Types::OneOf]
+    def one_of(&block)
+      Types::OneOf.new(&block)
+    end
   end
 end

lib/store_model/types.rb

@@ -1,12 +1,19 @@
 # frozen_string_literal: true
 
+require "store_model/types/base_single_type"
+require "store_model/types/base_array_type"
 require "store_model/types/json_type"
 require "store_model/types/array_type"
 require "store_model/types/enum_type"
+require "store_model/types/polymorphic_helper"
+require "store_model/types/polymorphic_type"
+require "store_model/types/polymorphic_array_type"
+require "store_model/types/one_of"
 
 module StoreModel
   # Contains all custom types.
   module Types
     class CastError < StandardError; end
+    class ExpandWrapperError < StandardError; end
   end
 end

lib/store_model/types/array_type.rb

@@ -6,7 +6,7 @@ module StoreModel
   module Types
     # Implements ActiveModel::Type::Value type for handling an array of
     # StoreModel::Model
-    class ArrayType < ActiveModel::Type::Value
+    class ArrayType < BaseArrayType
       # Initializes type for model class
       #
       # @param model_klass [StoreModel::Model] model class to handle
@@ -23,55 +23,7 @@ def type
         :array
       end
 
-      # Casts +value+ from DB or user to StoreModel::Model instance
-      #
-      # @param value [Object] a value to cast
-      #
-      # @return StoreModel::Model
-      def cast_value(value)
-        case value
-        when String then decode_and_initialize(value)
-        when Array then ensure_model_class(value)
-        when nil then value
-        else
-          raise StoreModel::Types::CastError,
-                "failed casting #{value.inspect}, only String or Array instances are allowed"
-        end
-      end
-
-      # Casts a value from the ruby type to a type that the database knows how
-      # to understand.
-      #
-      # @param value [Object] value to serialize
-      #
-      # @return [String] serialized value
-      def serialize(value)
-        case value
-        when Array
-          ActiveSupport::JSON.encode(value)
-        else
-          super
-        end
-      end
-
-      # Determines whether the mutable value has been modified since it was read
-      #
-      # @param raw_old_value [Object] old value
-      # @param new_value [Object] new value
-      #
-      # @return [Boolean]
-      def changed_in_place?(raw_old_value, new_value)
-        cast_value(raw_old_value) != new_value
-      end
-
-      private
-
-      # rubocop:disable Style/RescueModifier
-      def decode_and_initialize(array_value)
-        decoded = ActiveSupport::JSON.decode(array_value) rescue []
-        decoded.map { |attributes| cast_model_type_value(attributes) }
-      end
-      # rubocop:enable Style/RescueModifier
+      protected
 
       def ensure_model_class(array)
         array.map do |object|
@@ -86,6 +38,11 @@ def cast_model_type_value(value)
       def model_klass_type
         @model_klass_type ||= @model_klass.to_type
       end
+
+      def raise_cast_error(value)
+        raise StoreModel::Types::CastError,
+              "failed casting #{value.inspect}, only String or Array instances are allowed"
+      end
     end
   end
 end

lib/store_model/types/base_array_type.rb

@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+require "active_model"
+
+module StoreModel
+  module Types
+    # Implements ActiveModel::Type::Value type for handling an array of
+    # StoreModel::Model
+    class BaseArrayType < ActiveModel::Type::Value
+      # Returns type
+      #
+      # @return [Symbol]
+      def type
+        raise NotImplementedError
+      end
+
+      # Casts +value+ from DB or user to StoreModel::Model instance
+      #
+      # @param value [Object] a value to cast
+      #
+      # @return StoreModel::Model
+      def cast_value(value)
+        case value
+        when String then decode_and_initialize(value)
+        when Array then ensure_model_class(value)
+        when nil then value
+        else
+          raise_cast_error(value)
+        end
+      end
+
+      # Casts a value from the ruby type to a type that the database knows how
+      # to understand.
+      #
+      # @param value [Object] value to serialize
+      #
+      # @return [String] serialized value
+      def serialize(value)
+        case value
+        when Array
+          ActiveSupport::JSON.encode(value)
+        else
+          super
+        end
+      end
+
+      # Determines whether the mutable value has been modified since it was read
+      #
+      # @param raw_old_value [Object] old value
+      # @param new_value [Object] new value
+      #
+      # @return [Boolean]
+      def changed_in_place?(raw_old_value, new_value)
+        cast_value(raw_old_value) != new_value
+      end
+
+      protected
+
+      def ensure_model_class(array)
+        raise NotImplementedError
+      end
+
+      def cast_model_type_value(value)
+        raise NotImplementedError
+      end
+
+      def raise_cast_error(value)
+        raise NotImplementedError
+      end
+
+      private
+
+      # rubocop:disable Style/RescueModifier
+      def decode_and_initialize(array_value)
+        decoded = ActiveSupport::JSON.decode(array_value) rescue []
+        decoded.map { |attributes| cast_model_type_value(attributes) }
+      end
+      # rubocop:enable Style/RescueModifier
+    end
+  end
+end

lib/store_model/types/base_single_type.rb

@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+require "active_model"
+
+module StoreModel
+  module Types
+    # Implements ActiveModel::Type::Value type for handling an instance of StoreModel::Model
+    class BaseSingleType < ActiveModel::Type::Value
+      # Returns type
+      #
+      # @return [Symbol]
+      def type
+        raise NotImplementedError
+      end
+
+      # Casts +value+ from DB or user to StoreModel::Model instance
+      #
+      # @param value [Object] a value to cast
+      #
+      # @return StoreModel::Model
+      def cast_value(value)
+        raise NotImplementedError
+      end
+
+      # Determines whether the mutable value has been modified since it was read
+      #
+      # @param raw_old_value [Object] old value
+      # @param new_value [Object] new value
+      #
+      # @return [Boolean]
+      def changed_in_place?(raw_old_value, new_value)
+        cast_value(raw_old_value) != new_value
+      end
+
+      protected
+
+      def raise_cast_error(value)
+        raise NotImplementedError
+      end
+
+      def model_instance(value)
+        raise NotImplementedError
+      end
+
+      private
+
+      # rubocop:disable Style/RescueModifier
+      def decode_and_initialize(value)
+        decoded = ActiveSupport::JSON.decode(value) rescue nil
+        model_instance(decoded) unless decoded.nil?
+      rescue ActiveModel::UnknownAttributeError => e
+        handle_unknown_attribute(decoded, e)
+      end
+      # rubocop:enable Style/RescueModifier
+
+      def handle_unknown_attribute(value, exception)
+        attribute = exception.attribute.to_sym
+        value_symbolized = value.symbolize_keys
+
+        cast_value(value_symbolized.except(attribute)).tap do |configuration|
+          configuration.unknown_attributes[attribute.to_s] = value_symbolized[attribute]
+        end
+      end
+    end
+  end
+end

lib/store_model/types/json_type.rb

@@ -5,7 +5,7 @@
 module StoreModel
   module Types
     # Implements ActiveModel::Type::Value type for handling an instance of StoreModel::Model
-    class JsonType < ActiveModel::Type::Value
+    class JsonType < BaseSingleType
       # Initializes type for model class
       #
       # @param model_klass [StoreModel::Model] model class to handle
@@ -30,7 +30,7 @@ def type
       def cast_value(value)
         case value
         when String then decode_and_initialize(value)
-        when Hash then @model_klass.new(value)
+        when Hash then model_instance(value)
         when @model_klass, nil then value
         else raise_cast_error(value)
         end
@@ -53,40 +53,16 @@ def serialize(value)
         end
       end
 
-      # Determines whether the mutable value has been modified since it was read
-      #
-      # @param raw_old_value [Object] old value
-      # @param new_value [Object] new value
-      #
-      # @return [Boolean]
-      def changed_in_place?(raw_old_value, new_value)
-        cast_value(raw_old_value) != new_value
-      end
-
       private
 
-      # rubocop:disable Style/RescueModifier
-      def decode_and_initialize(value)
-        decoded = ActiveSupport::JSON.decode(value) rescue nil
-        @model_klass.new(decoded) unless decoded.nil?
-      rescue ActiveModel::UnknownAttributeError => e
-        handle_unknown_attribute(decoded, e)
-      end
-      # rubocop:enable Style/RescueModifier
-
       def raise_cast_error(value)
         raise StoreModel::Types::CastError,
               "failed casting #{value.inspect}, only String, " \
               "Hash or #{@model_klass.name} instances are allowed"
       end
 
-      def handle_unknown_attribute(value, exception)
-        attribute = exception.attribute.to_sym
-        value_symbolized = value.symbolize_keys
-
-        cast_value(value_symbolized.except(attribute)).tap do |configuration|
-          configuration.unknown_attributes[attribute.to_s] = value_symbolized[attribute]
-        end
+      def model_instance(value)
+        @model_klass.new(value)
       end
     end
   end

lib/store_model/types/one_of.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "active_model"
+
+module StoreModel
+  module Types
+    # Implements ActiveModel::Type::Value type for handling an array of
+    # StoreModel::Model
+    class OneOf
+      def initialize(&block)
+        @block = block
+      end
+
+      def to_type
+        Types::PolymorphicType.new(@block)
+      end
+
+      def to_array_type
+        Types::PolymorphicArrayType.new(@block)
+      end
+    end
+  end
+end