Enhance Highlight Customization using the columns Option

README.md

@@ -840,6 +840,37 @@ See the
 [documentation](https://www.postgresql.org/docs/current/static/textsearch-controls.html)
 for details on the meaning of each option.
 
+Use the `columns` option to create `pg_search_<custom_name>_highlight` with the necessary columns.
+
+
+```ruby
+class Person < ActiveRecord::Base
+ include PgSearch::Model
+ pg_search_scope :search,
+ against: [:portrait, :bio],
+ using: {
+ tsearch: {
+ highlight: {
+ columns: {
+ first: :portrait,
+ second: [:portrait, :bio]
+ }
+ }
+ }
+ }
+end
+
+Person.create!(
+ :portrait => "He's driven by an innate curiosity to discover every corner of Alberta.",
+ :bio => "Born in rural Alberta, where the buffalo roam."
+)
+
+first_match = Person.search("Alberta").with_pg_search_highlight.first
+first_match.pg_search_first_highlight => "He's driven by an innate curiosity to discover every corner of <b>Alberta</b>."
+first_match.pg_search_second_highlight => "He's driven by an innate curiosity to discover every corner of <b>Alberta</b>. Born in rural <b>Alberta</b>, where the buffalo roam."
+```
+
+
 #### :dmetaphone (Double Metaphone soundalike search)
 
 [Double Metaphone](http://en.wikipedia.org/wiki/Double_Metaphone) is an

lib/pg_search.rb

@@ -67,6 +67,20 @@ def message
  "to access the pg_search_highlight attribute on returned records"
  end
  end
+
+ class PgSearchHighlightCustomColumnsNotSelected < StandardError
+ attr_reader :attribute
+
+ def initialize(attribute)
+ @attribute = attribute
+ end
+
+ def message
+ "You must chain .with_pg_search_highlight after the pg_search_scope " \
+ "and define highlight: { columns: } option in pg_search_scope " \
+ "to access the #{attribute} attribute on returned records"
+ end
+ end
 end
 
 require "pg_search/railtie" if defined?(Rails::Railtie)

lib/pg_search/features/feature.rb

@@ -10,6 +10,8 @@ def self.valid_options
  %i[only sort_only]
  end
 
+ attr_reader :options
+
  delegate :connection, :quoted_table_name, to: :@model
 
  def initialize(query, options, all_columns, model, normalizer)
@@ -22,7 +24,7 @@ def initialize(query, options, all_columns, model, normalizer)
 
  private
 
- attr_reader :query, :options, :all_columns, :model, :normalizer
+ attr_reader :query, :all_columns, :model, :normalizer
 
  def document
  columns.map(&:to_sql).join(" || ' ' || ")

lib/pg_search/features/tsearch.rb

@@ -20,21 +20,33 @@ def rank
  arel_wrap(tsearch_rank)
  end
 
- def highlight
- arel_wrap(ts_headline)
+ def highlight(hl_columns = [])
+ arel_wrap(ts_headline(hl_columns))
  end
 
  private
 
- def ts_headline
+ def ts_headline(hl_columns)
  Arel::Nodes::NamedFunction.new("ts_headline", [
  dictionary,
- arel_wrap(document),
+ arel_wrap(document(hl_columns)),
  arel_wrap(tsquery),
  Arel::Nodes.build_quoted(ts_headline_options)
  ]).to_sql
  end
 
+ def document(hl_columns)
+ selected_columns(hl_columns).map(&:to_sql).join(" || ' ' || ")
+ end
+
+ def selected_columns(hl_columns)
+ return columns if hl_columns.blank?
+
+ columns.select do |column|
+ Array.wrap(hl_columns).map(&:to_s).include? column.name
+ end
+ end
+
  def ts_headline_options
  return "" unless options[:highlight].is_a?(Hash)
 

lib/pg_search/model.rb

@@ -38,6 +38,10 @@ def method_missing(symbol, *args)
  raise PgSearchHighlightNotSelected unless respond_to?(:pg_search_highlight)
 
  read_attribute(:pg_search_highlight)
+ when /^pg_search_(.+)_highlight$/
+ raise PgSearchHighlightCustomColumnsNotSelected.new(symbol) unless respond_to?(symbol)
+
+ read_attribute(symbol)
  else
  super
  end

lib/pg_search/scope_options.rb

@@ -38,11 +38,27 @@ def tsearch
  def with_pg_search_highlight
  scope = self
  scope = scope.select("#{table_name}.*") unless scope.select_values.any?
- scope.select("(#{highlight}) AS pg_search_highlight")
+ add_highlight_columns(scope)
  end
 
- def highlight
- tsearch.highlight.to_sql
+ def add_highlight_columns(scope)
+ if highlight_columns.present?
+ highlight_columns.each do |name, cols|
+ scope = scope.select("(#{highlight(cols)}) AS pg_search_#{name}_highlight")
+ end
+
+ scope
+ else
+ scope.select("(#{highlight}) AS pg_search_highlight")
+ end
+ end
+
+ def highlight(columns = [])
+ tsearch.highlight(columns).to_sql
+ end
+
+ def highlight_columns
+ tsearch.options.dig(:highlight, :columns)
  end
  end
 

spec/integration/pg_search_spec.rb

@@ -706,6 +706,40 @@
  expect(result.pg_search_highlight).to eq(%(<mark class="highlight">Let</mark> text<delim class="my_delim"><mark class="highlight">Let</mark> text))
  end
  end
+
+ context "with highlighting columns options" do
+ before do
+ ModelWithPgSearch.create!(
+ title: "The cat reads under the tree.",
+ content: "He hides behind a tree with colorful leaves."
+ )
+
+ ModelWithPgSearch.pg_search_scope :search_content,
+ against: %i[title content],
+ using: {
+ tsearch: {
+ highlight: {
+ columns: {
+ first: :title,
+ second: %i[title content]
+ }
+ }
+ }
+ }
+ end
+
+ it "adds a #pg_search_first_highlight method to each returned model record" do
+ result = ModelWithPgSearch.search_content("tree").with_pg_search_highlight.first
+
+ expect(result.pg_search_first_highlight).to eq(%(The cat reads under the <b>tree</b>.))
+ end
+
+ it "adds a #pg_search_second_highlight method to each returned model record" do
+ result = ModelWithPgSearch.search_content("tree").with_pg_search_highlight.first
+
+ expect(result.pg_search_second_highlight).to eq(%(The cat reads under the <b>tree</b>. He hides behind a <b>tree</b> with colorful leaves.))
+ end
+ end
  end
 
  describe "ranking" do