_pg_searchable.md

This is a quick-n-dirty ActiveRecord module to quickly add full-text capabilities to a PostgreSQL table wihtout too much overhead.

Author: Ryan McGeary : http://github.com/rmm5t
License: MIT : https://rmm5t.mit-license.org/

pg_searchable.rb

# TL;DR: A poor-man's full-text search.
#
# This module employs a mechanism by which we can easily add left outer joins
# to queries (typically for full-text-like searches that need to dig into
# specific associations).
#
# One way to do this is to just use ActiveRecord's `eager_load` as part of a
# default scope, but this triggers multiple left outer joins for every single
# query, regardless of whether a search is being performed.
#
# These related associations are often displayed as part of any generic query,
# so a default scope that `includes` the associations often boosts performance
# and eliminates N+1 query problems.
#
# This module gives the best of both worlds. It makes it easy to set up a
# default scope using `includes`, but also provides a mechanism to easily
# perform an `eager_load` when necessary (using this module's custom
# `searching` criteria method). This works because combining `includes` with
# `references` gives the same behavior as `eager_load`.
#
# Usage:
#
#     class Company < ActiveRecord::Base
#       include PgSearchable
#       self.searchable_includes = [:contacts, :assets]
#       self.searchable_text     = %w[companies.name contacts.name assets.name]
#       self.searchable_literals = %w[contacts.email]
#     end
#
#     Company.search("john doe acme")
#     Company.search("john@acme")
#
# Author:  Ryan McGeary : http://github.com/rmm5t
# License: MIT          : https://rmm5t.mit-license.org/
module PgSearchable
  extend ActiveSupport::Concern

  included do
    mattr_accessor :searchable_includes
    mattr_accessor :searchable_text,     default: ["''"]
    mattr_accessor :searchable_literals, default: ["''"]
  end

  class_methods do
    def searching(*args)
      query = where(*args)
      if searchable_includes.present?
        query = query.includes(*searchable_includes)
        query = query.references(*searchable_includes) if args.compact.present?
      end
      query
    end

    def search(query)
      return searching(nil) if query.blank?
      text     = "array_to_string(Array[#{searchable_text.join(', ')}], ' ')"
      literals = "array_to_string(Array[#{searchable_literals.join(', ')}],  ' ')"
      searching("(#{text}) @@ :q OR (#{literals}) ilike :word", q: query, word: "%#{query}%")
    end
  end
end