Add configuration/hook for meta. (#54)

Author: beauby

Diff for: CHANGELOG.md

@@ -1,5 +1,6 @@
 ### Added
 
+* Default configuration and hooks for the `meta` parameter.
 * Default configuration and hooks for the `cache` parameter.
 * Default configuration and hooks for the `links` parameter.
 * Default configuration and hooks for the `fields` parameter.

Diff for: lib/generators/jsonapi/initializer/templates/initializer.rb

@@ -62,6 +62,10 @@
   # # A lambda/proc that will be eval'd in the controller context.
   # config.jsonapi_links = ->() { {} }
   #
+  # # Set default meta.
+  # # A lambda/proc that will be eval'd in the controller context.
+  # config.jsonapi_meta = ->() { nil }
+  #
   # # Set a default pagination scheme.
   # config.jsonapi_pagination = ->(_) { {} }
 end

Diff for: lib/jsonapi/rails/configuration.rb

@@ -35,6 +35,8 @@ module Configurable
 
       DEFAULT_JSONAPI_LINKS = ->() { {} }
 
+      DEFAULT_JSONAPI_META = ->() { nil }
+
       DEFAULT_JSONAPI_PAGINATION = ->(_) { {} }
 
       DEFAULT_CONFIG = {
@@ -45,6 +47,7 @@ module Configurable
         jsonapi_fields:  DEFAULT_JSONAPI_FIELDS,
         jsonapi_include: DEFAULT_JSONAPI_INCLUDE,
         jsonapi_links:   DEFAULT_JSONAPI_LINKS,
+        jsonapi_meta:    DEFAULT_JSONAPI_META,
         jsonapi_object:  DEFAULT_JSONAPI_OBJECT,
         jsonapi_pagination: DEFAULT_JSONAPI_PAGINATION
       }.freeze

Diff for: lib/jsonapi/rails/controller.rb

@@ -99,7 +99,7 @@ def jsonapi_errors_class
 
       # Hook for the jsonapi object.
       # Overridden by the `jsonapi_object` renderer option.
-      # @return [Hash]
+      # @return [Hash,nil]
       def jsonapi_object
         JSONAPI::Rails.config[:jsonapi_object]
       end
@@ -117,7 +117,7 @@ def jsonapi_cache
       end
 
       # Hook for default fields.
-      # @return [Hash{Symbol=>Array<Symbol>}]
+      # @return [Hash{Symbol=>Array<Symbol>},nil]
       def jsonapi_fields
         instance_exec(&JSONAPI::Rails.config[:jsonapi_fields])
       end
@@ -129,11 +129,17 @@ def jsonapi_include
       end
 
       # Hook for default links.
-      # @return [IncludeDirective]
+      # @return [Hash]
       def jsonapi_links
         instance_exec(&JSONAPI::Rails.config[:jsonapi_links])
       end
 
+      # Hook for default meta.
+      # @return [Hash,nil]
+      def jsonapi_meta
+        instance_exec(&JSONAPI::Rails.config[:jsonapi_meta])
+      end
+
       # Hook for pagination scheme.
       # @return [Hash]
       def jsonapi_pagination(resources)

Diff for: lib/jsonapi/rails/renderer.rb

@@ -32,6 +32,7 @@ def default_options(options, controller, resources)
           opts[:include] ||= controller.jsonapi_include
           opts[:jsonapi] = opts.delete(:jsonapi_object) ||
                            controller.jsonapi_object
+          opts[:meta] ||= controller.jsonapi_meta
         end
       end
       # rubocop:enable Metrics/MethodLength, Metrics/AbcSize

Diff for: spec/controller/meta_spec.rb

@@ -0,0 +1,73 @@
+require 'rails_helper'
+
+describe ActionController::Base, type: :controller do
+  context 'when using default configuration' do
+    controller do
+      def index
+        render jsonapi: nil
+      end
+    end
+
+    subject { JSON.parse(response.body) }
+
+    it 'does not add meta' do
+      get :index
+
+      expect(subject.key?('meta')).to be false
+    end
+  end
+
+  context 'when using a custom configuration' do
+    controller do
+      def index
+        render jsonapi: nil
+      end
+    end
+
+    subject { JSON.parse(response.body) }
+
+    it 'modifies serialized meta' do
+      with_config(jsonapi_meta: ->() { { foo: 'bar' } }) do
+        get :index
+      end
+
+      expect(subject['meta']).to eq('foo' => 'bar')
+    end
+  end
+
+  context 'when customizing jsonapi_meta hook' do
+    controller do
+      def index
+        render jsonapi: nil
+      end
+
+      def jsonapi_meta
+        { foo: 'bar' }
+      end
+    end
+
+    subject { JSON.parse(response.body) }
+
+    it 'modifies serialized meta' do
+      get :index
+
+      expect(subject['meta']).to eq('foo' => 'bar')
+    end
+  end
+
+  context 'when prividing meta renderer option' do
+    controller do
+      def index
+        render jsonapi: nil, meta: { foo: 'bar' }
+      end
+    end
+
+    subject { JSON.parse(response.body) }
+
+    it 'modifies serialized meta' do
+      get :index
+
+      expect(subject['meta']).to eq('foo' => 'bar')
+    end
+  end
+end