Merge pull request #2690 from projectblacklight/7.x-base-component

Extract a base component for blacklight

app/components/blacklight/constraint_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class ConstraintComponent < ::ViewComponent::Base
+  class ConstraintComponent < Blacklight::Component
     with_collection_parameter :facet_item_presenter
 
     def initialize(facet_item_presenter:, classes: 'filter', layout: Blacklight::ConstraintLayoutComponent)

app/components/blacklight/constraint_layout_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class ConstraintLayoutComponent < ::ViewComponent::Base
+  class ConstraintLayoutComponent < Blacklight::Component
     def initialize(value:, label: nil, remove_path: nil, classes: nil, search_state: nil)
       @value = value
       @label = label

app/components/blacklight/constraints_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class ConstraintsComponent < ::ViewComponent::Base
+  class ConstraintsComponent < Blacklight::Component
     include Blacklight::ContentAreasShim
 
     renders_many :query_constraints_area

app/components/blacklight/document/action_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render a bookmark widget to bookmark / unbookmark a document
-    class ActionComponent < ::ViewComponent::Base
+    class ActionComponent < Blacklight::Component
       with_collection_parameter :action
 
       # @param [Blacklight::Document] document

app/components/blacklight/document/actions_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render a bookmark widget to bookmark / unbookmark a document
-    class ActionsComponent < ::ViewComponent::Base
+    class ActionsComponent < Blacklight::Component
       renders_many :actions, (lambda do |action:, component: nil, **kwargs|
         component ||= action.component || Blacklight::Document::ActionComponent
         component.new(action: action, document: @document, options: @options, url_opts: @url_opts, link_classes: @link_classes, **kwargs)

app/components/blacklight/document/bookmark_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render a bookmark widget to bookmark / unbookmark a document
-    class BookmarkComponent < ::ViewComponent::Base
+    class BookmarkComponent < Blacklight::Component
       # @param [Blacklight::Document] document
       # @param [Boolean] checked
       # @param [Object] bookmark_path the rails route to use for bookmarks

app/components/blacklight/document/citation_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render citations for the document
-    class CitationComponent < ::ViewComponent::Base
+    class CitationComponent < Blacklight::Component
       DEFAULT_FORMATS = {
         'blacklight.citation.mla': :export_as_mla_citation_txt,
         'blacklight.citation.apa': :export_as_apa_citation_txt,

app/components/blacklight/document/group_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render the 'more like this' results from the response
-    class GroupComponent < ::ViewComponent::Base
+    class GroupComponent < Blacklight::Component
       with_collection_parameter :group
 
       # @param [Blacklight::Solr::Response::Group] group

app/components/blacklight/document/more_like_this_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render the 'more like this' results from the response
-    class MoreLikeThisComponent < ::ViewComponent::Base
+    class MoreLikeThisComponent < Blacklight::Component
       with_collection_parameter :document
 
       # @param [Blacklight::Document] document

app/components/blacklight/document/thumbnail_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Document
     # Render the thumbnail for the document
-    class ThumbnailComponent < ::ViewComponent::Base
+    class ThumbnailComponent < Blacklight::Component
       with_collection_parameter :presenter
 
       # @param [Blacklight::DocumentPresenter] presenter

app/components/blacklight/document_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class DocumentComponent < ::ViewComponent::Base
+  class DocumentComponent < Blacklight::Component
     include Blacklight::ContentAreasShim
 
     # Content appearing before the document

app/components/blacklight/document_metadata_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class DocumentMetadataComponent < ::ViewComponent::Base
+  class DocumentMetadataComponent < Blacklight::Component
     renders_many :fields, (lambda do |component: nil, **kwargs|
       (component || Blacklight::MetadataFieldComponent).new(**kwargs)
     end)

app/components/blacklight/document_title_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class DocumentTitleComponent < ::ViewComponent::Base
+  class DocumentTitleComponent < Blacklight::Component
     renders_many :before_title
     renders_many :after_title
     renders_many :actions

app/components/blacklight/facet_field_checkboxes_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldCheckboxesComponent < ::ViewComponent::Base
+  class FacetFieldCheckboxesComponent < Blacklight::Component
     def initialize(facet_field:, layout: nil)
       @facet_field = facet_field
       @layout = layout == false ? FacetFieldNoLayoutComponent : Blacklight::FacetFieldComponent

app/components/blacklight/facet_field_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldComponent < ::ViewComponent::Base
+  class FacetFieldComponent < Blacklight::Component
     include Blacklight::ContentAreasShim
 
     renders_one :label

app/components/blacklight/facet_field_filter_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldFilterComponent < ::ViewComponent::Base
+  class FacetFieldFilterComponent < Blacklight::Component
     def initialize(facet_field:)
       @facet_field = facet_field
     end

app/components/blacklight/facet_field_inclusive_constraint_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldInclusiveConstraintComponent < ::ViewComponent::Base
+  class FacetFieldInclusiveConstraintComponent < Blacklight::Component
     with_collection_parameter :facet_field
 
     def initialize(facet_field:, values: nil)

app/components/blacklight/facet_field_list_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldListComponent < ::ViewComponent::Base
+  class FacetFieldListComponent < Blacklight::Component
     def initialize(facet_field:, layout: nil)
       @facet_field = facet_field
       @layout = layout == false ? FacetFieldNoLayoutComponent : Blacklight::FacetFieldComponent

app/components/blacklight/facet_field_no_layout_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldNoLayoutComponent < ::ViewComponent::Base
+  class FacetFieldNoLayoutComponent < Blacklight::Component
     include Blacklight::ContentAreasShim
 
     renders_one :label

app/components/blacklight/facet_field_pagination_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetFieldPaginationComponent < ::ViewComponent::Base
+  class FacetFieldPaginationComponent < Blacklight::Component
     def initialize(facet_field:)
       @facet_field = facet_field
     end

app/components/blacklight/facet_item_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class FacetItemComponent < ::ViewComponent::Base
+  class FacetItemComponent < Blacklight::Component
     extend Deprecation
 
     with_collection_parameter :facet_item

app/components/blacklight/facet_item_pivot_component.rb

@@ -2,7 +2,7 @@
 
 module Blacklight
   # Render facet items and any subtree
-  class FacetItemPivotComponent < ::ViewComponent::Base
+  class FacetItemPivotComponent < Blacklight::Component
     # Somewhat arbitrary number; the only important thing is that
     # it is bigger than the number of leaf nodes in any collapsing
     # pivot facet on the page.

app/components/blacklight/hidden_search_state_component.rb

@@ -4,7 +4,7 @@ module Blacklight
   # Writes out zero or more <input type="hidden"> elements, completely
   # representing a hash passed in using Rails-style request parameters
   # for hashes nested with arrays and other hashes.
-  class HiddenSearchStateComponent < ::ViewComponent::Base
+  class HiddenSearchStateComponent < Blacklight::Component
     # @param [Hash] params
     def initialize(params:)
       Deprecation.warn(self, "Passing page as a parameter to HiddenSearchStateComponent is deprecated and will not be supported in Blacklight 8") if params.key?(:page)

app/components/blacklight/metadata_field_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class MetadataFieldComponent < ::ViewComponent::Base
+  class MetadataFieldComponent < Blacklight::Component
     with_collection_parameter :field
 
     # @param field [Blacklight::FieldPresenter]

app/components/blacklight/metadata_field_layout_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class MetadataFieldLayoutComponent < ::ViewComponent::Base
+  class MetadataFieldLayoutComponent < Blacklight::Component
     include Blacklight::ContentAreasShim
 
     with_collection_parameter :field

app/components/blacklight/response/facet_group_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Response
     # Render a group of facet fields
-    class FacetGroupComponent < ::ViewComponent::Base
+    class FacetGroupComponent < Blacklight::Component
       # @param [Blacklight::Response] response
       # @param [Array<String>] fields facet fields to render
       # @param [String] title the title of the facet group section

app/components/blacklight/response/pagination_component.rb

@@ -3,7 +3,7 @@
 module Blacklight
   module Response
     # Render a pagination widget for search results
-    class PaginationComponent < ::ViewComponent::Base
+    class PaginationComponent < Blacklight::Component
       # @param [Blacklight::Response] response
       # @param [Hash] html html options for the pagination container
       def initialize(response:, html: {}, **pagination_args)

app/components/blacklight/search_bar_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class SearchBarComponent < ::ViewComponent::Base
+  class SearchBarComponent < Blacklight::Component
     include Blacklight::ContentAreasShim
 
     renders_one :append

app/components/blacklight/search_context_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class SearchContextComponent < ::ViewComponent::Base
+  class SearchContextComponent < Blacklight::Component
     with_collection_parameter :search_context
 
     def initialize(search_context:, search_session:)

app/components/blacklight/start_over_button_component.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 module Blacklight
-  class StartOverButtonComponent < ::ViewComponent::Base
+  class StartOverButtonComponent < Blacklight::Component
     def call
       link_to t('blacklight.search.start_over'), start_over_path, class: 'catalog_startOverLink btn btn-primary'
     end

lib/blacklight.rb

@@ -7,6 +7,7 @@
 
 module Blacklight
   autoload :AbstractRepository, 'blacklight/abstract_repository'
+  autoload :Component, 'blacklight/component'
   autoload :Configuration, 'blacklight/configuration'
   autoload :Exceptions,  'blacklight/exceptions'
   autoload :Parameters,  'blacklight/parameters'

lib/blacklight/component.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Blacklight
+  class Component < ViewComponent::Base
+    class << self
+      # rubocop:disable Naming/MemoizedInstanceVariableName
+      def compiler
+        @__vc_compiler ||= EngineCompiler.new(self)
+      end
+      # rubocop:enable Naming/MemoizedInstanceVariableName
+    end
+
+    class EngineCompiler < ::ViewComponent::Compiler
+      # ViewComponent::Compiler locates and caches templates from sidecar files to the component source file.
+      # While this is sensible in a Rails application, it prevents component templates defined in an Engine
+      # from being overridden by an installing application without subclassing the component, which may also
+      # require modifying any partials rendering the component. This subclass of compiler overrides the template
+      # location algorithm to take the sidecar file names from the Engine, but look to see if a file of the
+      # same name existing in the installing application (ie, under Rails.root). If the latter exists, this
+      # compiler will cache that template instead of the engine-defined file; if not, the compiler will fall
+      # back to the engine-defined file.
+      def templates
+        @templates ||= begin
+          extensions = ActionView::Template.template_handler_extensions
+
+          component_class._sidecar_files(extensions).each_with_object([]) do |path, memo|
+            pieces = File.basename(path).split(".")
+            app_path = "#{Rails.root}/#{path.slice(path.index(component_class.view_component_path)..-1)}"
+
+            memo << {
+              path: File.exist?(app_path) ? app_path : path,
+              variant: pieces.second.split("+").second&.to_sym,
+              handler: pieces.last
+            }
+          end
+        end
+      end
+    end
+  end
+end

spec/lib/blacklight/component_spec.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+RSpec.describe Blacklight::Component do
+  let(:component_class) { Blacklight::DocumentTitleComponent }
+
+  context "subclassed" do
+    it "returns our Compiler implementation" do
+      expect(component_class.ancestors).to include described_class
+      expect(component_class.compiler).to be_a Blacklight::Component::EngineCompiler
+    end
+  end
+
+  describe Blacklight::Component::EngineCompiler do
+    subject(:compiler) { described_class.new(component_class) }
+
+    let(:original_compiler) { ViewComponent::Compiler.new(component_class) }
+    let(:original_path) { original_compiler.send(:templates).first[:path] }
+    let(:resolved_path) { compiler.templates.first[:path] }
+
+    context "without overrides" do
+      it "links to engine template" do
+        expect(resolved_path).not_to include(".internal_test_app")
+        expect(resolved_path).to eql(original_path)
+      end
+    end
+
+    context "with overrides" do
+      let(:path_match) do
+        Regexp.new(Regexp.escape(File.join(".internal_test_app", component_class.view_component_path)))
+      end
+
+      before do
+        allow(File).to receive(:exist?).and_call_original
+        allow(File).to receive(:exist?).with(path_match).and_return(true)
+      end
+
+      it "links to application template" do
+        expect(resolved_path).to include(".internal_test_app")
+        expect(resolved_path).not_to eql(original_path)
+      end
+    end
+  end
+end