Added a permission form that supports destroy and id. Fixes #67

app/forms/hydra_editor/form.rb

@@ -1,6 +1,9 @@
 module HydraEditor
   module Form
+    extend ActiveSupport::Autoload
+    autoload :Permissions
     extend ActiveSupport::Concern
+
     include Hydra::Presenter
     included do
       class_attribute :required_fields
@@ -50,7 +53,6 @@ def build_permitted_params
             permitted << term
           end
         end
-        permitted << { permissions_attributes: [:type, :name, :access] }
         permitted
       end
     end

app/forms/hydra_editor/form/permissions.rb

@@ -0,0 +1,23 @@
+module HydraEditor
+  module Form
+    module Permissions
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+
+        def build_permitted_params
+          permitted = super
+          permitted << { permissions_attributes: [:type, :name, :access, :id, :_destroy] }
+          permitted
+        end
+      end
+
+      # This is required so that fields_for will draw a nested form.
+      # See ActionView::Helpers#nested_attributes_association?
+      #   https://github.com/rails/rails/blob/a04c0619617118433db6e01b67d5d082eaaa0189/actionview/lib/action_view/helpers/form_helper.rb#L1890
+      def permissions_attributes= attributes
+        model.permissions_attributes= attributes
+      end
+    end
+  end
+end

spec/forms/hydra_editor_form_permissions_spec.rb

@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe HydraEditor::Form::Permissions do
+  class TestModel < ActiveFedora::Base
+    property :title, predicate: ::RDF::DC.title
+    property :creator, predicate: ::RDF::DC.creator, multiple: false
+  end
+
+  class TestForm
+    include HydraEditor::Form
+    include HydraEditor::Form::Permissions
+    self.model_class = TestModel
+    # Terms is the list of fields displayed by app/views/records/_form.html.erb
+    self.terms = [:title, :creator]
+  end
+
+  describe "model_attributes" do
+    let(:params) { ActionController::Parameters.new(title: [''], creator: 'bob', description: ['huh'], permissions_attributes: {'0' => { id: '123', _destroy: 'true' }}) }
+    subject { TestForm.model_attributes(params) }
+
+    it { is_expected.to eq('creator' => 'bob', 'title' => [],
+                           'permissions_attributes' => { '0' => { 'id' => '123', '_destroy' => 'true' } }) }
+  end
+
+  describe "permissions_attributes=" do
+    subject { TestForm.new(TestModel.new) }
+    it "should respond to permissions_attributes=" do
+      expect(subject).to respond_to(:permissions_attributes=)
+    end
+  end
+end

spec/forms/hydra_editor_form_spec.rb

@@ -16,6 +16,13 @@ class TestForm
   describe "class methods" do
     subject { TestForm.model_name }
     it { is_expected.to eq 'TestModel' }
+
+    describe "model_attributes" do
+      let(:params) { ActionController::Parameters.new(title: [''], creator: 'bob', description: ['huh']) }
+      subject { TestForm.model_attributes(params) }
+
+      it { is_expected.to eq('creator' => 'bob', 'title' => []) }
+    end
   end
 
   let(:object) { TestModel.new(title: ['foo', 'bar'], creator: 'baz') }