resource.rb in alba-1.4.0

- old
+ new

@@ -6,11 +6,11 @@
 module Alba
   # This module represents what should be serialized
   module Resource
     # @!parse include InstanceMethods
     # @!parse extend ClassMethods
-    DSLS = {_attributes: {}, _key: nil, _transform_key_function: nil, _transforming_root_key: false, _on_error: nil}.freeze
+    DSLS = {_attributes: {}, _key: nil, _key_for_collection: nil, _meta: nil, _transform_key_function: nil, _transforming_root_key: false, _on_error: nil}.freeze # rubocop:disable Layout/LineLength
     private_constant :DSLS
 
     WITHIN_DEFAULT = Object.new.freeze
     private_constant :WITHIN_DEFAULT
 
@@ -31,25 +31,33 @@
     module InstanceMethods
       attr_reader :object, :params
 
       # @param object [Object] the object to be serialized
       # @param params [Hash] user-given Hash for arbitrary data
-      # @param within [Hash] determines what associations to be serialized. If not set, it serializes all associations.
+      # @param within [Object, nil, false, true] determines what associations to be serialized. If not set, it serializes all associations.
       def initialize(object, params: {}, within: WITHIN_DEFAULT)
         @object = object
         @params = params.freeze
         @within = within
         DSLS.each_key { |name| instance_variable_set("@#{name}", self.class.public_send(name)) }
       end
 
       # Serialize object into JSON string
       #
-      # @param key [Symbol]
+      # @param key [Symbol, nil, true] DEPRECATED, use root_key instead
+      # @param root_key [Symbol, nil, true]
+      # @param meta [Hash] metadata for this seialization
       # @return [String] serialized JSON string
-      def serialize(key: nil)
-        key = key.nil? ? _key : key
-        hash = key && key != '' ? {key.to_s => serializable_hash} : serializable_hash
+      def serialize(key: nil, root_key: nil, meta: {})
+        warn '`key` option to `serialize` method is deprecated, use `root_key` instead.' if key
+        key = key.nil? && root_key.nil? ? fetch_key : root_key || key
+        hash = if key && key != ''
+                 h = {key.to_s => serializable_hash}
+                 hash_with_metadata(h, meta)
+               else
+                 serializable_hash
+               end
         Alba.encoder.call(hash)
       end
 
       # A Hash for serialization
       #
@@ -59,21 +67,35 @@
       end
       alias to_hash serializable_hash
 
       private
 
+      def hash_with_metadata(hash, meta)
+        base = @_meta ? instance_eval(&@_meta) : {}
+        metadata = base.merge(meta)
+        hash[:meta] = metadata unless metadata.empty?
+        hash
+      end
+
+      def fetch_key
+        collection? ? _key_for_collection : _key
+      end
+
+      def _key_for_collection
+        return @_key_for_collection.to_s unless @_key_for_collection == true && Alba.inferring
+
+        key = resource_name.pluralize
+        transforming_root_key? ? transform_key(key) : key
+      end
+
       # @return [String]
       def _key
         return @_key.to_s unless @_key == true && Alba.inferring
 
-        transforming_root_key? ? transform_key(key_from_resource_name) : key_from_resource_name
+        transforming_root_key? ? transform_key(resource_name) : resource_name
       end
 
-      def key_from_resource_name
-        collection? ? resource_name.pluralize : resource_name
-      end
-
       def resource_name
         self.class.name.demodulize.delete_suffix('Resource').underscore
       end
 
       def transforming_root_key?
@@ -103,34 +125,27 @@
       end
 
       def conditional_attribute(object, key, attribute)
         condition = attribute.last
         arity = condition.arity
+        # We can return early to skip fetch_attribute
         return [] if arity <= 1 && !instance_exec(object, &condition)
 
         fetched_attribute = fetch_attribute(object, attribute.first)
-        attr = if attribute.first.is_a?(Alba::Association)
-                 attribute.first.object
-               else
-                 fetched_attribute
-               end
+        attr = attribute.first.is_a?(Alba::Association) ? attribute.first.object : fetched_attribute
         return [] if arity >= 2 && !instance_exec(object, attr, &condition)
 
         [key, fetched_attribute]
       end
 
       def handle_error(error, object, key, attribute)
         on_error = @_on_error || Alba._on_error
         case on_error
-        when :raise, nil
-          raise
-        when :nullify
-          [key, nil]
-        when :ignore
-          []
-        when Proc
-          on_error.call(error, object, key, attribute, self.class)
+        when :raise, nil then raise
+        when :nullify then [key, nil]
+        when :ignore then []
+        when Proc then on_error.call(error, object, key, attribute, self.class)
         else
           raise ::Alba::Error, "Unknown on_error: #{on_error.inspect}"
         end
       end
 
@@ -141,38 +156,31 @@
         @_transform_key_function.call(key.to_s)
       end
 
       def fetch_attribute(object, attribute)
         case attribute
-        when Symbol
-          object.public_send attribute
-        when Proc
-          instance_exec(object, &attribute)
-        when Alba::One, Alba::Many
-          within = check_within(attribute.name.to_sym)
-          return unless within
-
-          attribute.to_hash(object, params: params, within: within)
-        when TypedAttribute
-          attribute.value(object)
+        when Symbol then object.public_send attribute
+        when Proc then instance_exec(object, &attribute)
+        when Alba::One, Alba::Many then yield_if_within(attribute.name.to_sym) { |within| attribute.to_hash(object, params: params, within: within) }
+        when TypedAttribute then attribute.value(object)
         else
           raise ::Alba::Error, "Unsupported type of attribute: #{attribute.class}"
         end
       end
 
+      def yield_if_within(association_name)
+        within = check_within(association_name)
+        yield(within) if within
+      end
+
       def check_within(association_name)
         case @within
-        when WITHIN_DEFAULT # Default value, doesn't check within tree
-          WITHIN_DEFAULT
-        when Hash # Traverse within tree
-          @within.fetch(association_name, nil)
-        when Array # within tree ends with Array
-          @within.find { |item| item.to_sym == association_name }
-        when Symbol # within tree could end with Symbol
-          @within == association_name
-        when nil, true, false # In these cases, Alba stops serialization here.
-          false
+        when WITHIN_DEFAULT then WITHIN_DEFAULT # Default value, doesn't check within tree
+        when Hash then @within.fetch(association_name, nil) # Traverse within tree
+        when Array then @within.find { |item| item.to_sym == association_name }
+        when Symbol then @within == association_name
+        when nil, true, false then false # Stop here
         else
           raise Alba::Error, "Unknown type for within option: #{@within.class}"
         end
       end
 
@@ -189,15 +197,20 @@
       def inherited(subclass)
         super
         DSLS.each_key { |name| subclass.instance_variable_set("@#{name}", instance_variable_get("@#{name}").clone) }
       end
 
+      # Defining methods for DSLs and disable parameter number check since for users' benefits increasing params is fine
+      # rubocop:disable Metrics/ParameterLists
+
       # Set multiple attributes at once
       #
       # @param attrs [Array<String, Symbol>]
-      # @param if [Boolean] condition to decide if it should render these attributes
-      # @param attrs_with_types [Hash] attributes with name in its key and type and optional type converter in its value
+      # @param if [Proc] condition to decide if it should serialize these attributes
+      # @param attrs_with_types [Hash<[Symbol, String], [Array<Symbol, Proc>, Symbol]>]
+      #   attributes with name in its key and type and optional type converter in its value
+      # @return [void]
       def attributes(*attrs, if: nil, **attrs_with_types) # rubocop:disable Naming/MethodParameterName
         if_value = binding.local_variable_get(:if)
         assign_attributes(attrs, if_value)
         assign_attributes_with_types(attrs_with_types, if_value)
       end
@@ -222,43 +235,49 @@
       private :assign_attributes_with_types
 
       # Set an attribute with the given block
       #
       # @param name [String, Symbol] key name
-      # @param options [Hash] option hash including `if` that is a  condition to render
+      # @param options [Hash<Symbol, Proc>]
+      # @option options [Proc] if a condition to decide if this attribute should be serialized
       # @param block [Block] the block called during serialization
       # @raise [ArgumentError] if block is absent
+      # @return [void]
       def attribute(name, **options, &block)
         raise ArgumentError, 'No block given in attribute method' unless block
 
         @_attributes[name.to_sym] = options[:if] ? [block, options[:if]] : block
       end
 
       # Set One association
       #
-      # @param name [String, Symbol]
-      # @param condition [Proc]
-      # @param resource [Class<Alba::Resource>]
-      # @param key [String, Symbol] used as key when given
-      # @param options [Hash] option hash including `if` that is a  condition to render
+      # @param name [String, Symbol] name of the association, used as key when `key` param doesn't exist
+      # @param condition [Proc, nil] a Proc to modify the association
+      # @param resource [Class<Alba::Resource>, String, nil] representing resource for this association
+      # @param key [String, Symbol, nil] used as key when given
+      # @param options [Hash<Symbol, Proc>]
+      # @option options [Proc] if a condition to decide if this association should be serialized
       # @param block [Block]
+      # @return [void]
       # @see Alba::One#initialize
       def one(name, condition = nil, resource: nil, key: nil, **options, &block)
         nesting = self.name&.rpartition('::')&.first
         one = One.new(name: name, condition: condition, resource: resource, nesting: nesting, &block)
         @_attributes[key&.to_sym || name.to_sym] = options[:if] ? [one, options[:if]] : one
       end
       alias has_one one
 
       # Set Many association
       #
-      # @param name [String, Symbol]
-      # @param condition [Proc]
-      # @param resource [Class<Alba::Resource>]
-      # @param key [String, Symbol] used as key when given
-      # @param options [Hash] option hash including `if` that is a  condition to render
+      # @param name [String, Symbol] name of the association, used as key when `key` param doesn't exist
+      # @param condition [Proc, nil] a Proc to filter the collection
+      # @param resource [Class<Alba::Resource>, String, nil] representing resource for this association
+      # @param key [String, Symbol, nil] used as key when given
+      # @param options [Hash<Symbol, Proc>]
+      # @option options [Proc] if a condition to decide if this association should be serialized
       # @param block [Block]
+      # @return [void]
       # @see Alba::Many#initialize
       def many(name, condition = nil, resource: nil, key: nil, **options, &block)
         nesting = self.name&.rpartition('::')&.first
         many = Many.new(name: name, condition: condition, resource: resource, nesting: nesting, &block)
         @_attributes[key&.to_sym || name.to_sym] = options[:if] ? [many, options[:if]] : many
@@ -266,20 +285,46 @@
       alias has_many many
 
       # Set key
       #
       # @param key [String, Symbol]
+      # @deprecated Use {#root_key} instead
       def key(key)
+        warn '[DEPRECATION] `key` is deprecated, use `root_key` instead.'
         @_key = key.respond_to?(:to_sym) ? key.to_sym : key
       end
 
+      # Set root key
+      #
+      # @param key [String, Symbol]
+      # @param key_for_collection [String, Symbol]
+      # @raise [NoMethodError] when key doesn't respond to `to_sym` method
+      def root_key(key, key_for_collection = nil)
+        @_key = key.to_sym
+        @_key_for_collection = key_for_collection&.to_sym
+      end
+
       # Set key to true
       #
+      # @deprecated Use {#root_key!} instead
       def key!
+        warn '[DEPRECATION] `key!` is deprecated, use `root_key!` instead.'
         @_key = true
+        @_key_for_collection = true
       end
 
+      # Set root key to true
+      def root_key!
+        @_key = true
+        @_key_for_collection = true
+      end
+
+      # Set metadata
+      def meta(&block)
+        @_meta = block
+      end
+
       # Delete attributes
       # Use this DSL in child class to ignore certain attributes
       #
       # @param attributes [Array<String, Symbol>]
       def ignoring(*attributes)
@@ -296,17 +341,20 @@
         @_transform_key_function = KeyTransformFactory.create(type.to_sym)
         @_transforming_root_key = root
       end
 
       # Set error handler
+      # If this is set it's used as a error handler overriding global one
       #
-      # @param [Symbol] handler
-      # @param [Block]
+      # @param handler [Symbol] `:raise`, `:ignore` or `:nullify`
+      # @param block [Block]
       def on_error(handler = nil, &block)
         raise ArgumentError, 'You cannot specify error handler with both Symbol and block' if handler && block
         raise ArgumentError, 'You must specify error handler with either Symbol or block' unless handler || block
 
         @_on_error = handler || block
       end
+
+      # rubocop:enable Metrics/ParameterLists
     end
   end
 end