Add serialization helpers

 - Added `index` attribute type that automatically generates a link list compatible with media_types-serialization.
 - Added support for `collection` to automatically look up a previously defined schema when passing a view.

Author: thexa4

CHANGELOG.md

@@ -4,6 +4,8 @@
 
  - Add ability to define multiple versions using one block.
  - Added ability to mark certain attributes as optional when validating with `loose: true` and required otherwise.
+ - Added `index` attribute type that automatically generates a link list compatible with media_types-serialization.
+ - Added support for `collection` to automatically look up a previously defined schema when passing a view.
 
 ## 2.1.1
 

lib/media_types/errors.rb

@@ -15,5 +15,11 @@ def initialize(mod:)
         super(format('Unable to change key type expectation for %<mod>s since its current expectation is already used', mod: mod.name))
       end
     end
+
+    class CollectionDefinitionNotFound < StandardError
+      def initialize(current, target)
+        super(format('Unable to use %<target>s as a collection inside %<current>s, no such schema has been defined.', current: current, target: target))
+      end
+    end
   end
 end

lib/media_types/scheme.rb

@@ -94,11 +94,13 @@ class Scheme
     #
     # @see MissingValidation
     #
-    def initialize(allow_empty: false, expected_type: ::Object, &block)
+    def initialize(allow_empty: false, expected_type: ::Object, current_type: nil, registry: nil, &block)
       self.rules = Rules.new(allow_empty: allow_empty, expected_type: expected_type)
       self.type_attributes = {}
       self.fixtures = []
       self.asserted_sane = false
+      @registry = registry
+      @current_type = current_type
 
       instance_exec(&block) if block_given?
     end
@@ -270,7 +272,7 @@ def any(scheme = nil, expected_type: ::Hash, allow_empty: false, &block)
         return rules.default = Attribute.new(scheme)
       end
 
-      rules.default = Scheme.new(allow_empty: allow_empty, expected_type: expected_type, &block)
+      rules.default = Scheme.new(allow_empty: allow_empty, expected_type: expected_type, registry: @registry, current_type: @current_type, &block)
     end
 
     ##
@@ -348,10 +350,20 @@ def not_strict
     #   MyMedia.valid?({ foo: [{ required: 'test', number: 42 }, { required: 'other', number: 0 }] })
     #   # => true
     #
-    def collection(key, scheme = nil, allow_empty: false, expected_type: ::Array, optional: false, &block)
+    def collection(key, scheme = nil, view: nil, allow_empty: false, expected_type: ::Array, optional: false, &block)
       raise ConflictingTypeDefinitionError, 'You cannot apply a block to a non-hash typed collection, either remove the type or the block' if scheme != ::Hash && block_given? && !scheme.nil?
 
       unless block_given?
+        if scheme.nil?
+          dependent_key = @current_type.as_key.dup
+          dependent_key[1] = view
+
+          unless @registry.has_key? dependent_key
+            raise Errors::CollectionDefinitionNotFound.new(@current_type.override_suffix('json').to_s, @current_type.view(view).override_suffix('json').to_s)
+          end
+          scheme = @registry[dependent_key]
+        end
+
         return rules.add(
           key,
           EnumerationOfType.new(
@@ -363,7 +375,16 @@ def collection(key, scheme = nil, allow_empty: false, expected_type: ::Array, op
         )
       end
 
-      rules.add(key, Scheme.new(allow_empty: allow_empty, expected_type: expected_type, &block), optional: optional)
+      rules.add(key, Scheme.new(allow_empty: allow_empty, expected_type: expected_type, registry: @registry, current_type: @current_type, &block), optional: optional)
+    end
+
+    ##
+    # Expect an index of links
+    #
+    def index(optional: false)
+      collection(:_links, optional: optional) do
+        link :_self  
+      end
     end
 
     ##

lib/media_types/validations.rb

@@ -25,7 +25,7 @@ class Validations
     # @see Constructable
     # @see Scheme
     #
-    def initialize(media_type, registry = {}, scheme = Scheme.new, &block)
+    def initialize(media_type, registry = {}, scheme = Scheme.new(registry: registry, current_type: media_type), &block)
       self.media_type = media_type
       self.registry = registry.merge!(media_type.as_key => scheme)
       self.scheme = scheme

test/media_types/dsl/collection_test.rb

@@ -305,6 +305,33 @@ def self.organisation
         end
       end
 
+      
+      class IndexCollectionType
+        include MediaTypes::Dsl
+
+        def self.organisation
+          'acme'
+        end
+
+        use_name 'index_test'
+
+        validations do
+          version 1 do
+            attribute :bar, Numeric
+          end
+
+          view :index do
+            version 1 do
+              collection :_embedded
+            end
+          end
+        end
+      end
+
+      def test_index_collections
+        assert IndexCollectionType.view(:index).version(1).validate!({ _embedded: [{ bar: 42 }] }), 'Expected input to be valid'
+      end
+
     end
   end
 end