pg_bigmを使った検索を有効にする

.github/workflows/_check.yaml

@@ -41,9 +41,11 @@ jobs:
       IMAGEMAGICK_SRC: 7.1.0-50.tar.gz
       SLACK_API_TOKEN: xoxb-dummy
       SLACK_MESSAGE_CHANNEL: '#test'
+    permissions:
+      packages: read
     services:
       db:
-        image: postgres:12.14
+        image: ghcr.io/codeforjapan/postgresql_bigm:12-latest
         ports:
           - 5432:5432
         env:

app/models/decidim/searchable_resource.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "pg_search"
+
+module Decidim
+  # A Searchable Resource.
+  # This is a model to a PgSearch table that indexes all searchable resources.
+  # This table is used to perform textual searches.
+  #
+  # Main attributes are:
+  # - locale: One entry per locale is required, so each resource will be indexed once per locale.
+  # - content_a: The most relevant textual content.
+  # - content_b: The second most relevant textual content.
+  # - content_c: The third most relevant textual content.
+  # - content_d: The less relevant textual content.
+  # - datetime:  The timestamp that places this resource in the line of time. Used as second criteria (first is text relevance) for sorting.
+  #
+  class SearchableResource < ApplicationRecord
+    include PgSearch::Model
+
+    belongs_to :organization,
+               foreign_key: "decidim_organization_id",
+               class_name: "Decidim::Organization"
+    belongs_to :scope,
+               foreign_key: "decidim_scope_id",
+               class_name: "Decidim::Scope",
+               optional: true
+    belongs_to :resource, polymorphic: true
+    belongs_to :decidim_participatory_space, polymorphic: true, optional: true
+
+    validates :locale, uniqueness: { scope: [:decidim_organization_id, :resource_type, :resource_id] } # rubocop:disable Rails/UniqueValidationWithoutIndex
+
+    pg_search_scope :global_search,
+                    against: { content_a: "A", content_b: "B", content_c: "C", content_d: "D" },
+                    ranked_by: ":bigram",
+                    using: :bigram
+  end
+end

app/packs/stylesheets/decidim/decidim_application.scss

@@ -9,6 +9,5 @@
 @import "./cfj/buttons";
 @import "./cfj/comment_content";
 @import "./cfj/forms";
-@import "./cfj/search";
 @import "./cfj/media_print";
 @import "./cfj/ql_html_editor";

config/initializers/pg_search_override.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "pg_search"
+
+Rails.application.config.to_prepare do
+  ## define `PgSearch::Features::Bigram` to use pg_bigm extension
+  module PgSearch
+    module Features
+      class Bigram < Feature
+        def conditions
+          if options[:threshold]
+            Arel::Nodes::Grouping.new(
+              similarity.gteq(options[:threshold])
+            )
+          else
+            Arel::Nodes::Grouping.new(
+              Arel::Nodes::InfixOperation.new(
+                infix_operator,
+                normalized_document,
+                normalized_query_for_like
+              )
+            )
+          end
+        end
+
+        def rank
+          Arel::Nodes::Grouping.new(similarity)
+        end
+
+        private
+
+        def similarity_function
+          "bigm_similarity"
+        end
+
+        def infix_operator
+          "like"
+        end
+
+        def similarity
+          Arel::Nodes::NamedFunction.new(
+            similarity_function,
+            [
+              normalized_query,
+              normalized_document
+            ]
+          )
+        end
+
+        def normalized_document
+          Arel::Nodes::Grouping.new(Arel.sql(normalize(document)))
+        end
+
+        def normalized_query_for_like
+          sanitized_query = connection.quote(query)
+          Arel.sql("likequery(#{normalize(sanitized_query)})")
+        end
+
+        def normalized_query
+          sanitized_query = connection.quote(query)
+          Arel.sql(normalize(sanitized_query))
+        end
+      end
+    end
+  end
+
+  ## override `PgSearch::ScopeOptions::FEATURE_CLASSES`
+  PgSearch::ScopeOptions::FEATURE_CLASSES = {
+    dmetaphone: PgSearch::Features::DMetaphone,
+    tsearch: PgSearch::Features::TSearch,
+    trigram: PgSearch::Features::Trigram,
+    bigram: PgSearch::Features::Bigram
+  }.freeze
+end

config/routes.rb

@@ -4,7 +4,6 @@
 Rails.application.routes.draw do
   # Redirect to Metadecidim Japan
   get "/", to: redirect("https://meta.diycities.jp/"), constraints: { host: "www.diycities.jp" }
-  get "/search", to: redirect("/")
 
   mount Decidim::Core::Engine => "/"
   # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html

db/migrate/20240713180919_enable_pg_bigm_extension.rb

@@ -0,0 +1,9 @@
+class EnablePgBigmExtension < ActiveRecord::Migration[6.1]
+  def up
+    enable_extension 'pg_bigm'
+  end
+
+  def down
+    disable_extension 'pg_bigm'
+  end
+end

docs/UPGRADE.md

@@ -71,6 +71,10 @@ Decidim本体のバージョンを更新する際、特に注意が必要な内
 
   https://github.com/codeforjapan/decidim-cfj/pull/415 で追加されたファイル。ディベートでconclusionsに空文字列を許すための修正。
 
+* `app/models/decidim/searchable_resource.rb`
+
+  https://github.com/codeforjapan/decidim-cfj/pull/615 で追加したファイル。pg_searchのfeatureとしてbigram(`pg_bigm`)に対応させるためのもの。
+
 * `app/uploaders/decidim/cw/application_uploader.rb`
 
   https://github.com/decidim/decidim/issues/6720 や https://github.com/codeforjapan/decidim-cfj/issues/101 などの対応のために導入。