Configurable deserialization + reverse mapping (#10)

* Deserialize all fields.
* Make blocks return hash instead of using fields method.
* Ensure valid payload.
* Make reverse mapping available.

jsonapi-deserializable.gemspec

@@ -14,6 +14,8 @@ Gem::Specification.new do |spec|
   spec.files         = Dir['README.md', 'lib/**/*']
   spec.require_path  = 'lib'
 
+  spec.add_dependency 'jsonapi-parser', '0.1.1.beta3'
+
   spec.add_development_dependency 'rake', '>=0.9'
   spec.add_development_dependency 'rspec', '~>3.4'
   spec.add_development_dependency 'codecov', '~> 0.1'

lib/jsonapi/deserializable/relationship.rb

@@ -1,15 +1,17 @@
-require 'jsonapi/deserializable/relationship_dsl'
+require 'jsonapi/deserializable/relationship/dsl'
+require 'jsonapi/parser/relationship'
 
 module JSONAPI
   module Deserializable
     class Relationship
-      include RelationshipDSL
+      extend DSL
 
       class << self
         attr_accessor :has_one_block, :has_many_block
       end
 
       def self.inherited(klass)
+        super
         klass.has_one_block  = has_one_block
         klass.has_many_block = has_many_block
       end
@@ -19,9 +21,11 @@ module JSONAPI
       end
 
       def initialize(payload)
+        Parser::Relationship.parse!(payload)
         @document = payload
         @data = payload['data']
         deserialize!
+        freeze
       end
 
       def to_hash
@@ -32,31 +36,32 @@ module JSONAPI
       private
 
       def deserialize!
-        @hash = {}
-        return unless @document.key?('data')
+        @hash =
           if @data.is_a?(Array)
-          deserialize_has_many!
+            deserialize_has_many
           elsif @data.nil? || @data.is_a?(Hash)
-          deserialize_has_one!
+            deserialize_has_one
           end
       end
 
-      def deserialize_has_one!
-        return unless self.class.has_one_block
+      def deserialize_has_one
         id = @data && @data['id']
         type = @data && @data['type']
-        instance_exec(@document, id, type, &self.class.has_one_block)
+        if self.class.has_one_block
+          self.class.has_one_block.call(@document, id, type)
+        else
+          { id: id, type: type }
+        end
       end
 
-      def deserialize_has_many!
-        return unless self.class.has_many_block
+      def deserialize_has_many
         ids = @data.map { |ri| ri['id'] }
         types = @data.map { |ri| ri['type'] }
-        instance_exec(@document, ids, types, &self.class.has_many_block)
+        if self.class.has_many_block
+          self.class.has_many_block.call(@document, ids, types)
+        else
+          { ids: ids, types: types }
         end
-
-      def field(hash)
-        @hash.merge!(hash)
       end
     end
   end

lib/jsonapi/deserializable/relationship/dsl.rb

@@ -0,0 +1,15 @@
+module JSONAPI
+  module Deserializable
+    class Relationship
+      module DSL
+        def has_one(&block)
+          self.has_one_block = block
+        end
+
+        def has_many(&block)
+          self.has_many_block = block
+        end
+      end
+    end
+  end
+end

lib/jsonapi/deserializable/relationship_dsl.rb

@@ -1,21 +0,0 @@
-module JSONAPI
-  module Deserializable
-    module RelationshipDSL
-      def self.included(base)
-        base.extend(ClassMethods)
-      end
-
-      module ClassMethods
-        def has_one(&block)
-          block ||= proc { |rel| field relationship: rel }
-          self.has_one_block = block
-        end
-
-        def has_many(&block)
-          block ||= proc { |rel| field relationship: rel }
-          self.has_many_block = block
-        end
-      end
-    end
-  end
-end

lib/jsonapi/deserializable/resource.rb

@@ -1,21 +1,28 @@
-require 'jsonapi/deserializable/resource_dsl'
+require 'jsonapi/deserializable/resource/configuration'
+require 'jsonapi/deserializable/resource/dsl'
+require 'jsonapi/parser/resource'
 
 module JSONAPI
   module Deserializable
     class Resource
-      include ResourceDSL
+      extend DSL
 
       class << self
         attr_accessor :type_block, :id_block, :attr_blocks,
-                      :has_one_rel_blocks, :has_many_rel_blocks
+                      :has_one_rel_blocks, :has_many_rel_blocks,
+                      :configuration
       end
 
+      @class_cache = {}
+
+      self.configuration       = Configuration.new
       self.attr_blocks         = {}
       self.has_one_rel_blocks  = {}
       self.has_many_rel_blocks = {}
 
       def self.inherited(klass)
         super
+        klass.configuration       = configuration.dup
         klass.type_block          = type_block
         klass.id_block            = id_block
         klass.attr_blocks         = attr_blocks.dup
@@ -23,11 +30,20 @@ module JSONAPI
         klass.has_many_rel_blocks = has_many_rel_blocks.dup
       end
 
+      def self.configure
+        yield(configuration)
+      end
+
+      def self.[](name)
+        @class_cache[name] ||= Class.new(self)
+      end
+
       def self.call(payload)
         new(payload).to_h
       end
 
       def initialize(payload)
+        Parser::Resource.parse!(payload)
         @document = payload
         @data = @document['data']
         @type = @data['type']
@@ -35,6 +51,7 @@ module JSONAPI
         @attributes    = @data['attributes'] || {}
         @relationships = @data['relationships'] || {}
         deserialize!
+        freeze
       end
 
       def to_hash
@@ -42,69 +59,97 @@ module JSONAPI
       end
       alias to_h to_hash
 
+      attr_reader :reverse_mapping
+
       private
 
+      def configuration
+        self.class.configuration
+      end
+
+      def register_mappings(keys, path)
+        keys.each do |k|
+          @reverse_mapping[k] = path
+        end
+      end
+
       def deserialize!
-        @hash = {}
-        deserialize_type!
-        deserialize_id!
-        deserialize_attrs!
-        deserialize_rels!
+        @reverse_mapping = {}
+        hashes = [deserialize_type, deserialize_id,
+                  deserialize_attrs, deserialize_rels]
+        @hash = hashes.reduce({}, :merge)
       end
 
-      def deserialize_type!
-        return unless @type && self.class.type_block
-        instance_exec(@type, &self.class.type_block)
+      def deserialize_type
+        block = self.class.type_block || configuration.default_type
+        hash = block.call(@type)
+        register_mappings(hash.keys, '/data/type')
+        hash
       end
 
-      def deserialize_id!
-        return unless @id && self.class.id_block
-        instance_exec(@id, &self.class.id_block)
+      def deserialize_id
+        return {} unless @id
+        block = self.class.id_block || configuration.default_id
+        hash  = block.call(@id)
+        register_mappings(hash.keys, '/data/id')
+        hash
       end
 
-      def deserialize_attrs!
-        self.class.attr_blocks.each do |attr, block|
-          next unless @attributes.key?(attr)
-          instance_exec(@attributes[attr], &block)
-        end
+      def deserialize_attrs
+        @attributes
+          .map { |key, val| deserialize_attr(key, val) }
+          .reduce({}, :merge)
       end
 
-      def deserialize_rels!
-        deserialize_has_one_rels!
-        deserialize_has_many_rels!
+      def deserialize_attr(key, val)
+        hash = if self.class.attr_blocks.key?(key)
+                 self.class.attr_blocks[key].call(val)
+               else
+                 configuration.default_attribute.call(key, val)
+               end
+        register_mappings(hash.keys, "/data/attributes/#{key}")
+        hash
       end
 
-      def deserialize_has_one_rels!
-        self.class.has_one_rel_blocks.each do |key, block|
-          rel = @relationships[key]
-          next unless rel && (rel['data'].nil? || rel['data'].is_a?(Hash))
-          deserialize_has_one_rel!(rel, &block)
-        end
+      def deserialize_rels
+        @relationships
+          .map { |key, val| deserialize_rel(key, val) }
+          .reduce({}, :merge)
       end
 
-      def deserialize_has_one_rel!(rel, &block)
-        id = rel['data'] && rel['data']['id']
-        type = rel['data'] && rel['data']['type']
-        instance_exec(rel, id, type, &block)
+      def deserialize_rel(key, val)
+        hash = if val['data'].is_a?(Array)
+                 deserialize_has_many_rel(key, val)
+               else
+                 deserialize_has_one_rel(key, val)
+               end
+        register_mappings(hash.keys, "/data/relationships/#{key}")
+        hash
       end
 
-      def deserialize_has_many_rels!
-        self.class.has_many_rel_blocks.each do |key, block|
-          rel = @relationships[key]
-          next unless rel && rel['data'].is_a?(Array)
-          deserialize_has_many_rel!(rel, &block)
+      # rubocop: disable Metrics/AbcSize
+      def deserialize_has_one_rel(key, val)
+        id   = val['data'] && val['data']['id']
+        type = val['data'] && val['data']['type']
+        if self.class.has_one_rel_blocks.key?(key)
+          self.class.has_one_rel_blocks[key].call(val, id, type)
+        else
+          configuration.default_has_one.call(key, val, id, type)
         end
       end
+      # rubocop: enable Metrics/AbcSize
 
-      def deserialize_has_many_rel!(rel, &block)
-        ids = rel['data'].map { |ri| ri['id'] }
-        types = rel['data'].map { |ri| ri['type'] }
-        instance_exec(rel, ids, types, &block)
+      # rubocop: disable Metrics/AbcSize
+      def deserialize_has_many_rel(key, val)
+        ids   = val['data'].map { |ri| ri['id'] }
+        types = val['data'].map { |ri| ri['type'] }
+        if self.class.has_many_rel_blocks.key?(key)
+          self.class.has_many_rel_blocks[key].call(val, ids, types)
+        else
+          configuration.default_has_many.call(key, val, ids, types)
         end
-
-      def field(hash)
-        @hash.merge!(hash)
       end
+      # rubocop: enable Metrics/AbcSize
     end
   end
 end

lib/jsonapi/deserializable/resource/configuration.rb

@@ -0,0 +1,28 @@
+module JSONAPI
+  module Deserializable
+    class Resource
+      class Configuration
+        DEFAULT_TYPE_BLOCK = proc { |t| { type: t } }
+        DEFAULT_ID_BLOCK   = proc { |i| { id: i } }
+        DEFAULT_ATTR_BLOCK = proc { |k, v| { k.to_sym => v } }
+        DEFAULT_HAS_ONE_BLOCK = proc do |k, _, i, t|
+          { "#{k}_id".to_sym => i, "#{k}_type".to_sym => t }
+        end
+        DEFAULT_HAS_MANY_BLOCK = proc do |k, _, i, t|
+          { "#{k}_ids".to_sym => i, "#{k}_types".to_sym => t }
+        end
+
+        attr_accessor :default_type, :default_id, :default_attribute,
+                      :default_has_one, :default_has_many
+
+        def initialize
+          self.default_type       = DEFAULT_TYPE_BLOCK
+          self.default_id         = DEFAULT_ID_BLOCK
+          self.default_attribute  = DEFAULT_ATTR_BLOCK
+          self.default_has_one    = DEFAULT_HAS_ONE_BLOCK
+          self.default_has_many   = DEFAULT_HAS_MANY_BLOCK
+        end
+      end
+    end
+  end
+end

lib/jsonapi/deserializable/resource/dsl.rb

@@ -0,0 +1,27 @@
+module JSONAPI
+  module Deserializable
+    class Resource
+      module DSL
+        def type(&block)
+          self.type_block = block
+        end
+
+        def id(&block)
+          self.id_block = block
+        end
+
+        def attribute(key, &block)
+          attr_blocks[key.to_s] = block
+        end
+
+        def has_one(key, &block)
+          has_one_rel_blocks[key.to_s] = block
+        end
+
+        def has_many(key, &block)
+          has_many_rel_blocks[key.to_s] = block
+        end
+      end
+    end
+  end
+end

lib/jsonapi/deserializable/resource_dsl.rb

@@ -1,39 +0,0 @@
-module JSONAPI
-  module Deserializable
-    module ResourceDSL
-      def self.included(base)
-        base.extend(ClassMethods)
-      end
-
-      module ClassMethods
-        def type(&block)
-          block ||= proc { |type| field type: type }
-          self.type_block = block
-        end
-
-        def id(&block)
-          block ||= proc { |id| field id: id }
-          self.id_block = block
-        end
-
-        def attribute(key, options = {}, &block)
-          unless block
-            options[:key] ||= key.to_sym
-            block = proc { |attr| field key => attr }
-          end
-          attr_blocks[key.to_s] = block
-        end
-
-        def has_one(key, &block)
-          block ||= proc { |rel| field key.to_sym => rel }
-          has_one_rel_blocks[key.to_s] = block
-        end
-
-        def has_many(key, &block)
-          block ||= proc { |rel| field key.to_sym => rel }
-          has_many_rel_blocks[key.to_s] = block
-        end
-      end
-    end
-  end
-end

spec/relationship/has_many_spec.rb

@@ -4,9 +4,7 @@ describe JSONAPI::Deserializable::Relationship, '.has_many' do
   let(:deserializable_foo) do
     Class.new(JSONAPI::Deserializable::Relationship) do
       has_many do |rel, ids, types|
-        field foo_ids: ids
-        field foo_types: types
-        field foo_rel: rel
+        { foo_ids: ids, foo_types: types, foo_rel: rel }
       end
     end
   end
@@ -29,12 +27,10 @@ describe JSONAPI::Deserializable::Relationship, '.has_many' do
       expect(actual).to eq(expected)
     end
 
-    it 'defaults to creating a relationship field' do
-      klass = Class.new(JSONAPI::Deserializable::Relationship) do
-        has_many
-      end
+    it 'defaults to creating ids and types fields' do
+      klass = Class.new(JSONAPI::Deserializable::Relationship)
       actual = klass.call(payload)
-      expected = { relationship: payload }
+      expected = { ids: %w(bar baz), types: %w(foo foo) }
 
       expect(actual).to eq(expected)
     end
@@ -51,20 +47,19 @@ describe JSONAPI::Deserializable::Relationship, '.has_many' do
   end
 
   context 'data is absent' do
-    it 'does not create corresponding fields' do
+    it 'raises InvalidDocument' do
       payload = {}
-      actual = deserializable_foo.call(payload)
-      expected = {}
 
-      expect(actual).to eq(expected)
+      expect { deserializable_foo.call(payload) }
+        .to raise_error(JSONAPI::Parser::InvalidDocument)
     end
   end
 
   context 'relationship is not to-many' do
-    it 'does not create corresponding fields' do
+    it 'falls back to default to-one deserialization scheme' do
       payload = { 'data' => nil }
       actual = deserializable_foo.call(payload)
-      expected = {}
+      expected = { id: nil, type: nil }
 
       expect(actual).to eq(expected)
     end

spec/relationship/has_one_spec.rb

@@ -4,9 +4,7 @@ describe JSONAPI::Deserializable::Relationship, '.has_one' do
   let(:deserializable_foo) do
     Class.new(JSONAPI::Deserializable::Relationship) do
       has_one do |rel, id, type|
-        field foo_id: id
-        field foo_type: type
-        field foo_rel: rel
+        { foo_id: id, foo_type: type, foo_rel: rel }
       end
     end
   end
@@ -23,12 +21,10 @@ describe JSONAPI::Deserializable::Relationship, '.has_one' do
       expect(actual).to eq(expected)
     end
 
-    it 'defaults to creating a relationship field' do
-      klass = Class.new(JSONAPI::Deserializable::Relationship) do
-        has_one
-      end
+    it 'defaults to creating id and type fields' do
+      klass = Class.new(JSONAPI::Deserializable::Relationship)
       actual = klass.call(payload)
-      expected = { relationship: payload }
+      expected = { id: 'bar', type: 'foo' }
 
       expect(actual).to eq(expected)
     end
@@ -45,20 +41,19 @@ describe JSONAPI::Deserializable::Relationship, '.has_one' do
   end
 
   context 'data is absent' do
-    it 'does not create corresponding fields' do
+    it 'raises InvalidDocument' do
       payload = {}
-      actual = deserializable_foo.call(payload)
-      expected = {}
 
-      expect(actual).to eq(expected)
+      expect { deserializable_foo.call(payload) }
+        .to raise_error(JSONAPI::Parser::InvalidDocument)
     end
   end
 
   context 'relationship is not to-one' do
-    it 'does not create corresponding fields' do
+    it 'falls back to default has_many deserialization scheme ' do
       payload = { 'data' => [] }
       actual = deserializable_foo.call(payload)
-      expected = {}
+      expected = { ids: [], types: [] }
 
       expect(actual).to eq(expected)
     end

spec/resource/DSL/attribute_spec.rb

@@ -9,21 +9,21 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
       }
     }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
-      attribute(:foo) { |foo| field foo: foo }
+      attribute(:foo) { |foo| Hash[foo: foo] }
     end
     actual = klass.call(payload)
-    expected = { foo: 'bar' }
+    expected = { foo: 'bar', type: 'foo' }
 
     expect(actual).to eq(expected)
   end
 
   it 'does not create corresponding field if attribute is absent' do
-    payload = { 'data' => { 'type' => 'foo' }, 'attributes' => {} }
+    payload = { 'data' => { 'type' => 'foo', 'attributes' => {} } }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
-      attribute(:foo) { |foo| field foo: foo }
+      attribute(:foo) { |foo| Hash[foo: foo] }
     end
     actual = klass.call(payload)
-    expected = {}
+    expected = { type: 'foo' }
 
     expect(actual).to eq(expected)
   end
@@ -31,10 +31,10 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
   it 'does not create corresponding field if no attribute specified' do
     payload = { 'data' => { 'type' => 'foo' } }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
-      attribute(:foo) { |foo| field foo: foo }
+      attribute(:foo) { |foo| Hash[foo: foo] }
     end
     actual = klass.call(payload)
-    expected = {}
+    expected = { type: 'foo' }
 
     expect(actual).to eq(expected)
   end
@@ -46,11 +46,9 @@ describe JSONAPI::Deserializable::Resource, '.attribute' do
         'attributes' => { 'foo' => 'bar' }
       }
     }
-    klass = Class.new(JSONAPI::Deserializable::Resource) do
-      attribute :foo
-    end
+    klass = JSONAPI::Deserializable::Resource
     actual = klass.call(payload)
-    expected = { foo: 'bar' }
+    expected = { foo: 'bar', type: 'foo' }
 
     expect(actual).to eq(expected)
   end

spec/resource/DSL/has_many_spec.rb

@@ -4,9 +4,7 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
   let(:deserializable_foo) do
     Class.new(JSONAPI::Deserializable::Resource) do
       has_many :foo do |rel, ids, types|
-        field foo_ids: ids
-        field foo_types: types
-        field foo_rel: rel
+        Hash[foo_ids: ids, foo_types: types, foo_rel: rel]
       end
     end
   end
@@ -31,17 +29,16 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
     it 'creates corresponding fields' do
       actual = deserializable_foo.call(payload)
       expected = { foo_ids: %w(bar baz), foo_types: %w(foo foo),
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['data']['relationships']['foo'],
+                   type: 'foo' }
 
       expect(actual).to eq(expected)
     end
 
-    it 'defaults to creating a field of the same name' do
-      klass = Class.new(JSONAPI::Deserializable::Resource) do
-        has_many :foo
-      end
+    it 'defaults to creating a #{name}_ids and #{name}_types fields' do
+      klass = JSONAPI::Deserializable::Resource
       actual = klass.call(payload)
-      expected = { foo: payload['data']['relationships']['foo'] }
+      expected = { foo_ids: %w(bar baz), foo_types: %w(foo foo), type: 'foo' }
 
       expect(actual).to eq(expected)
     end
@@ -61,7 +58,8 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
       }
       actual = deserializable_foo.call(payload)
       expected = { foo_ids: [], foo_types: [],
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['data']['relationships']['foo'],
+                   type: 'foo' }
 
       expect(actual).to eq(expected)
     end
@@ -76,7 +74,7 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
         }
       }
       actual = deserializable_foo.call(payload)
-      expected = {}
+      expected = { type: 'foo' }
 
       expect(actual).to eq(expected)
     end
@@ -90,27 +88,7 @@ describe JSONAPI::Deserializable::Resource, '.has_many' do
         }
       }
       actual = deserializable_foo.call(payload)
-      expected = {}
-
-      expect(actual).to eq(expected)
-    end
-  end
-
-  context 'relationship is not to-many' do
-    it 'does not create corresponding fields' do
-      payload = {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {
-            'foo' => {
-              'data' => { 'type' => 'foo', 'id' => 'bar' }
-            }
-          }
-        }
-      }
-
-      actual = deserializable_foo.call(payload)
-      expected = {}
+      expected = { type: 'foo' }
 
       expect(actual).to eq(expected)
     end

spec/resource/DSL/has_one_spec.rb

@@ -4,9 +4,7 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
   let(:deserializable_foo) do
     Class.new(JSONAPI::Deserializable::Resource) do
       has_one :foo do |rel, id, type|
-        field foo_id: id
-        field foo_type: type
-        field foo_rel: rel
+        Hash[foo_id: id, foo_type: type, foo_rel: rel]
       end
     end
   end
@@ -28,23 +26,22 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
     it 'creates corresponding fields' do
       actual = deserializable_foo.call(payload)
       expected = { foo_id: 'bar', foo_type: 'foo',
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['data']['relationships']['foo'],
+                   type: 'foo' }
 
       expect(actual).to eq(expected)
     end
 
-    it 'defaults to creating a field of the same name' do
-      klass = Class.new(JSONAPI::Deserializable::Resource) do
-        has_one :foo
-      end
+    it 'defaults to creating #{name}_id and #{name}_type' do
+      klass = JSONAPI::Deserializable::Resource
       actual = klass.call(payload)
-      expected = { foo: payload['data']['relationships']['foo'] }
+      expected = { foo_id: 'bar', foo_type: 'foo', type: 'foo' }
 
       expect(actual).to eq(expected)
     end
   end
 
-  context 'relationship is nil' do
+  context 'relationship value is nil' do
     it 'creates corresponding fields' do
       payload = {
         'data' => {
@@ -56,9 +53,11 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
           }
         }
       }
+
       actual = deserializable_foo.call(payload)
       expected = { foo_id: nil, foo_type: nil,
-                   foo_rel: payload['data']['relationships']['foo'] }
+                   foo_rel: payload['data']['relationships']['foo'],
+                   type: 'foo' }
 
       expect(actual).to eq(expected)
     end
@@ -73,7 +72,7 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
         }
       }
       actual = deserializable_foo.call(payload)
-      expected = {}
+      expected = { type: 'foo' }
 
       expect(actual).to eq(expected)
     end
@@ -87,26 +86,7 @@ describe JSONAPI::Deserializable::Resource, '.has_one' do
         }
       }
       actual = deserializable_foo.call(payload)
-      expected = {}
-
-      expect(actual).to eq(expected)
-    end
-  end
-
-  context 'relationship is not to-one' do
-    it 'does not create corresponding fields' do
-      payload = {
-        'data' => {
-          'type' => 'foo',
-          'relationships' => {
-            'foo' => {
-              'data' => []
-            }
-          }
-        }
-      }
-      actual = deserializable_foo.call(payload)
-      expected = {}
+      expected = { type: 'foo' }
 
       expect(actual).to eq(expected)
     end

spec/resource/DSL/id_spec.rb

@@ -4,10 +4,10 @@ describe JSONAPI::Deserializable::Resource, '.id' do
   it 'creates corresponding field if id is present' do
     payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
-      id { |i| field id: i }
+      id { |i| Hash[id: i] }
     end
     actual = klass.call(payload)
-    expected = { id: 'bar' }
+    expected = { id: 'bar', type: 'foo' }
 
     expect(actual).to eq(expected)
   end
@@ -15,21 +15,19 @@ describe JSONAPI::Deserializable::Resource, '.id' do
   it 'does not create corresponding field if id is absent' do
     payload = { 'data' => { 'type' => 'foo' } }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
-      id { |i| field id: i }
+      id { |i| Hash[id: i] }
     end
     actual = klass.call(payload)
-    expected = {}
+    expected = { type: 'foo' }
 
     expect(actual).to eq(expected)
   end
 
   it 'defaults to creating an id field' do
     payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
-    klass = Class.new(JSONAPI::Deserializable::Resource) do
-      id
-    end
+    klass = JSONAPI::Deserializable::Resource
     actual = klass.call(payload)
-    expected = { id: 'bar' }
+    expected = { id: 'bar', type: 'foo' }
 
     expect(actual).to eq(expected)
   end

spec/resource/DSL/type_spec.rb

@@ -4,7 +4,7 @@ describe JSONAPI::Deserializable::Resource, '.type' do
   it 'creates corresponding field' do
     payload = { 'data' => { 'type' => 'foo' } }
     klass = Class.new(JSONAPI::Deserializable::Resource) do
-      type { |t| field type: t }
+      type { |t| Hash[type: t] }
     end
     actual = klass.call(payload)
     expected = { type: 'foo' }
@@ -14,9 +14,7 @@ describe JSONAPI::Deserializable::Resource, '.type' do
 
   it 'defaults to creating a type field' do
     payload = { 'data' => { 'type' => 'foo' } }
-    klass = Class.new(JSONAPI::Deserializable::Resource) do
-      type
-    end
+    klass = JSONAPI::Deserializable::Resource
     actual = klass.call(payload)
     expected = { type: 'foo' }
 

spec/resource/configuration_spec.rb

@@ -0,0 +1,108 @@
+require 'spec_helper'
+
+describe JSONAPI::Deserializable::Resource, '.configure' do
+  it 'overrides global default attribute deserialization scheme' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'attributes' => {
+          'foo' => 'bar',
+          'baz' => 'foo'
+        }
+      }
+    }
+    begin
+      JSONAPI::Deserializable::Resource.configure do |cfg|
+        cfg.default_attribute = proc do |key, value|
+          { "custom_#{key}".to_sym => value }
+        end
+      end
+      klass = JSONAPI::Deserializable::Resource
+      actual = klass.call(payload)
+      expected = { custom_foo: 'bar', custom_baz: 'foo', type: 'foo' }
+
+      expect(actual).to eq(expected)
+    ensure
+      JSONAPI::Deserializable::Resource.configuration =
+        JSONAPI::Deserializable::Resource::Configuration.new
+    end
+  end
+
+  it 'overrides default attribute deserialization scheme' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'attributes' => {
+          'foo' => 'bar',
+          'baz' => 'foo'
+        }
+      }
+    }
+    JSONAPI::Deserializable::Resource[:c1].configure do |cfg|
+      cfg.default_attribute = proc do |key, value|
+        { "custom_#{key}".to_sym => value }
+      end
+    end
+    klass = JSONAPI::Deserializable::Resource[:c1]
+    actual = klass.call(payload)
+    expected = { custom_foo: 'bar', custom_baz: 'foo', type: 'foo' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'overrides the default has_many relationship deserialization scheme' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => [{ 'type' => 'bar', 'id' => 'baz' },
+                       { 'type' => 'foo', 'id' => 'bar' }]
+          },
+          'bar' => {
+            'data' => [{ 'type' => 'baz', 'id' => 'foo' },
+                       { 'type' => 'baz', 'id' => 'buz' }]
+          }
+        }
+      }
+    }
+    JSONAPI::Deserializable::Resource[:c1].configure do |cfg|
+      cfg.default_has_many = proc do |name, _value, ids, types|
+        { "custom_#{name}_ids".to_sym => ids,
+          "custom_#{name}_types".to_sym => types }
+      end
+    end
+    klass = JSONAPI::Deserializable::Resource[:c1]
+    actual = klass.call(payload)
+    expected = { custom_foo_ids: %w(baz bar), custom_foo_types: %w(bar foo),
+                 custom_bar_ids: %w(foo buz), custom_bar_types: %w(baz baz),
+                 type: 'foo' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'overrides the default has_one relationship deserialization scheme' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => { 'data' => { 'type' => 'bar', 'id' => 'baz' } },
+          'bar' => { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+        }
+      }
+    }
+    JSONAPI::Deserializable::Resource[:c1].configure do |cfg|
+      cfg.default_has_one = proc do |name, _value, id, type|
+        { "custom_#{name}_id".to_sym => id,
+          "custom_#{name}_type".to_sym => type }
+      end
+    end
+    klass = JSONAPI::Deserializable::Resource[:c1]
+    actual = klass.call(payload)
+    expected = { custom_foo_id: 'baz', custom_foo_type: 'bar',
+                 custom_bar_id: 'bar', custom_bar_type: 'foo',
+                 type: 'foo' }
+
+    expect(actual).to eq(expected)
+  end
+end

spec/resource/reverse_mapping_spec.rb

@@ -0,0 +1,231 @@
+require 'spec_helper'
+
+describe JSONAPI::Deserializable::Resource, '#reverse_mapping' do
+  it 'generates reverse mapping for default type' do
+    payload = { 'data' => { 'type' => 'foo' } }
+    klass = JSONAPI::Deserializable::Resource
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for overriden type' do
+    payload = { 'data' => { 'type' => 'foo' } }
+    klass = Class.new(JSONAPI::Deserializable::Resource) do
+      type { |t| { custom_type: t } }
+    end
+    actual = klass.new(payload).reverse_mapping
+    expected = { custom_type: '/data/type' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for default id' do
+    payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+    klass = JSONAPI::Deserializable::Resource
+    actual = klass.new(payload).reverse_mapping
+    expected = { id: '/data/id', type: '/data/type' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for overriden id' do
+    payload = { 'data' => { 'type' => 'foo', 'id' => 'bar' } }
+    klass = Class.new(JSONAPI::Deserializable::Resource) do
+      id { |i| { custom_id: i } }
+    end
+    actual = klass.new(payload).reverse_mapping
+    expected = { custom_id: '/data/id', type: '/data/type' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for default attributes' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'attributes' => {
+          'foo' => 'bar',
+          'baz' => 'fiz'
+        }
+      }
+    }
+    klass = JSONAPI::Deserializable::Resource
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 foo: '/data/attributes/foo',
+                 baz: '/data/attributes/baz' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for locally overriden attributes' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'attributes' => {
+          'foo' => 'bar',
+          'baz' => 'fiz'
+        }
+      }
+    }
+    klass = Class.new(JSONAPI::Deserializable::Resource) do
+      attribute(:foo) { |foo| { custom_foo: foo } }
+    end
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 custom_foo: '/data/attributes/foo',
+                 baz: '/data/attributes/baz' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for globally overriden attributes' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'attributes' => {
+          'foo' => 'bar',
+          'baz' => 'fiz'
+        }
+      }
+    }
+    klass = Class.new(JSONAPI::Deserializable::Resource) do
+      attribute(:foo) { |foo| { other_foo: foo } }
+    end
+    klass.configure do |config|
+      config.default_attribute = proc do |key, value|
+        { "custom_#{key}".to_sym => value }
+      end
+    end
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 other_foo: '/data/attributes/foo',
+                 custom_baz: '/data/attributes/baz' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for default has_many' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => nil
+          },
+          'baz' => {
+            'data' => nil
+          }
+        }
+      }
+    }
+    klass = JSONAPI::Deserializable::Resource
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 foo_id: '/data/relationships/foo',
+                 foo_type: '/data/relationships/foo',
+                 baz_id: '/data/relationships/baz',
+                 baz_type: '/data/relationships/baz' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for overriden has_one' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => nil
+          },
+          'baz' => {
+            'data' => nil
+          }
+        }
+      }
+    }
+    klass = Class.new(JSONAPI::Deserializable::Resource) do
+      has_one(:foo) do |_val, id, type|
+        { other_foo_id: id,
+          other_foo_type: type }
+      end
+    end
+    klass.configure do |config|
+      config.default_has_one = proc do |key, _val, id, type|
+        { "custom_#{key}_id".to_sym => id,
+          "custom_#{key}_type".to_sym => type }
+      end
+    end
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 other_foo_id: '/data/relationships/foo',
+                 other_foo_type: '/data/relationships/foo',
+                 custom_baz_id: '/data/relationships/baz',
+                 custom_baz_type: '/data/relationships/baz' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for default has_many' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => []
+          },
+          'baz' => {
+            'data' => []
+          }
+        }
+      }
+    }
+    klass = JSONAPI::Deserializable::Resource
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 foo_ids: '/data/relationships/foo',
+                 foo_types: '/data/relationships/foo',
+                 baz_ids: '/data/relationships/baz',
+                 baz_types: '/data/relationships/baz' }
+
+    expect(actual).to eq(expected)
+  end
+
+  it 'generates reverse mapping for overriden has_many' do
+    payload = {
+      'data' => {
+        'type' => 'foo',
+        'relationships' => {
+          'foo' => {
+            'data' => []
+          },
+          'baz' => {
+            'data' => []
+          }
+        }
+      }
+    }
+    klass = Class.new(JSONAPI::Deserializable::Resource) do
+      has_many(:foo) do |_val, ids, types|
+        { other_foo_ids: ids,
+          other_foo_types: types }
+      end
+    end
+    klass.configure do |config|
+      config.default_has_many = proc do |key, _val, ids, types|
+        { "custom_#{key}_ids".to_sym => ids,
+          "custom_#{key}_types".to_sym => types }
+      end
+    end
+    actual = klass.new(payload).reverse_mapping
+    expected = { type: '/data/type',
+                 other_foo_ids: '/data/relationships/foo',
+                 other_foo_types: '/data/relationships/foo',
+                 custom_baz_ids: '/data/relationships/baz',
+                 custom_baz_types: '/data/relationships/baz' }
+
+    expect(actual).to eq(expected)
+  end
+end