Add support for Blacklight hit-highlighting in the full-text field

app/assets/javascripts/application.js

@@ -26,6 +26,7 @@
 //= require blacklight_gallery
 //= require blacklight_heatmaps
 //= require blacklight_oembed
+//= require full_text_collapse
 //= require index_status_typeahead
 //= require nested_related_items
 //= require openseadragon
@@ -37,4 +38,3 @@
 // For blacklight_range_limit built-in JS, if you don't want it you don't need
 // this:
 //= require 'blacklight_range_limit'
-

app/assets/javascripts/full_text_collapse.js

@@ -0,0 +1,21 @@
+Blacklight.onLoad(function(){
+  var uniqueId = (function() {
+  		var uuid = 0;
+
+  		return function(el) {
+        el.id = 'ui-id-' + ( ++uuid );
+  		};
+  	} )();
+
+  $('dd.blacklight-full_text_tesimv').addClass('collapse').each(function() {
+    $(this).attr('id', uniqueId(this));
+  });
+
+  $('dt.blacklight-full_text_tesimv').each(function() {
+    $(this).text($(this).text().replace(/:$/, ''));
+    $(this).attr('data-toggle', 'collapse');
+    $(this).attr('data-target', '#' + $(this).next('dd').attr('id'));
+  });
+
+  $('dd.blacklight-full_text_tesimv').collapse({ toggle: false });
+});

app/assets/stylesheets/base.scss

@@ -12,3 +12,4 @@
 @import "viewers";
 @import "modules/view_metadata";
 @import "modules/related_item";
+@import "modules/full_text_highlight";

app/assets/stylesheets/modules/full_text_highlight.scss

@@ -0,0 +1,32 @@
+dt.blacklight-full_text_tesimv {
+  @extend .h4;
+  cursor: pointer;
+  display: inline-block;
+  float: none;
+  text-align: initial;
+  width: auto;
+  // collapse carets shamelessly stolen from blacklight facets
+  &[data-toggle="collapse"]::after {
+    // symbol for "opening" panels
+    content: "\e114";
+    float: right;
+    font-family: "Glyphicons Halflings";
+    font-size: 0.8em;
+    line-height: normal;
+    padding-left: 2ch;
+  }
+
+  &.collapsed:after {
+    // symbol for "collapsed" panels
+    content: "\e080";
+  }
+}
+
+dd.blacklight-full_text_tesimv {
+  float: none;
+  margin-left: 0;
+
+  em {
+    font-weight: bold;
+  }
+}

app/controllers/catalog_controller.rb

@@ -24,7 +24,13 @@ class CatalogController < ApplicationController
     ## Default parameters to send to solr for all search-like requests. See also SolrHelper#solr_search_params
     config.default_solr_params = {
       qt: 'search',
-      fl: '*'
+      fl: '*',
+      hl: true,
+      'hl.fl' => 'full_text_tesimv',
+      'hl.snippets' => 5,
+      'hl.fragsize' => 240,
+      'hl.mergeContiguous' => true,
+      'hl.useFastVectorHighlighter' => true
     }
 
     config.default_autocomplete_solr_params = {
@@ -208,6 +214,15 @@ class CatalogController < ApplicationController
     config.add_index_field 'manuscript_number_tesim', label: 'Manuscript number'
     config.add_index_field 'range_labels_tesim', label: 'Section'
     config.add_index_field 'related_document_id_ssim', label: 'Manuscript', helper_method: :manuscript_link
+    config.add_index_field(
+      'full_text_tesimv',
+      if: lambda do |context, field_config, document|
+        full_text_highlight_exists_in_response?(context, field_config, document)
+      end,
+      label: 'Preview matches in document text',
+      highlight: true,
+      helper_method: :render_fulltext_highlight
+    )
     # "fielded" search configuration. Used by pulldown among other places.
     # For supported keys in hash, see rdoc for Blacklight::SearchFields
     #
@@ -352,4 +367,13 @@ def metadata
   def start_new_search_session?
     super && params[:format] != 'json'
   end
+
+  class << self
+    def full_text_highlight_exists_in_response?(context, config, document)
+      response = context.instance_variable_get(:@response)
+      document_highlight = response['highlighting'][document['id']]
+      return true if document_highlight.present? && document_highlight[config.key].present?
+      false
+    end
+  end
 end

app/helpers/application_helper.rb

@@ -25,6 +25,15 @@ def iiif_drag_n_drop(manifest, width: '40px')
     end
   end
 
+  def render_fulltext_highlight(args)
+    return if args[:value].blank?
+    safe_join(args[:value].map do |val|
+      content_tag('p') do
+        val
+      end
+    end, '')
+  end
+
   ##
   # Renders a viewer for an object with understanding of the context. In the
   # context of spotlight/catalog render the configured viewer. In other contexts

spec/features/full_text_highlight_spec.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.feature 'Full text highlighting' do
+  let(:exhibit) { create(:exhibit) }
+  let(:dor_harvester) { DorHarvester.new(druid_list: druid, exhibit: exhibit) }
+
+  before do
+    allow(Spotlight::Engine.config).to receive(:filter_resources_by_exhibit).and_return(false)
+    visit spotlight.search_exhibit_catalog_path(exhibit, q: 'structure')
+  end
+
+  it 'shows the full-text hightlight field and provides a toggle', js: true do
+    expect(page).to have_css('dt', text: 'Preview matches in document text')
+
+    expect(page).not_to have_css('dd p', text: 'about need for data structures capable of storing', visible: true)
+    page.find('dt', text: 'Preview matches in document text').click
+    expect(page).to have_css('dd p', text: 'about need for data structures capable of storing', visible: true)
+  end
+end