Rails controller strategy pattern via controller.instance_eval

example_controller_strategy_pattern.rb

class MyController < ApplicationController
  # ...
  def search_all
    return unless (@search_phrase = search_phrase_or_redirect)

    doc_types = %w[Episode ForumPost Series]
    notification_payload = { action: "search_all", search_phrase: @search_phrase,
                             doc_types: doc_types, pagy_limit: RESULT_PAGE_SIZE }

    ActiveSupport::Notifications.instrument('search_render', notification_payload) do
      Current.search_strategy.search_all(self, @search_phrase, doc_types, RESULT_PAGE_SIZE)
    end
  end
  # ...
end



class MyStrategy
  # ... 
  def search_all(controller, search_phrase, doc_types, limit)
    doc_search_results = find_docs(search_phrase, doc_types)

    controller.instance_eval do
      @pagy, @search_results = pagy(doc_search_results, limit: limit)
      render "my_strategy/search_results", locals: { search_phrase: @search_phrase, search_results: @search_results, pagy: @pagy }
    end
  end
  # ...
end

class MyController < ApplicationController
  # ...
  def search_all
    return unless (@search_phrase = search_phrase_or_redirect)

    doc_types = %w[Episode ForumPost Series]
    notification_payload = { action: "search_all", search_phrase: @search_phrase,
                             doc_types: doc_types, pagy_limit: RESULT_PAGE_SIZE }

    ActiveSupport::Notifications.instrument('search_render', notification_payload) do
      results, path = Current.search_strategy.search_all(self, @search_phrase, doc_types)
      @pagy, @search_results = pagy(results, limit: RESULT_PAGE_SIZE)
      render "#{path}/search_results", locals: { search_phrase: @search_phrase, search_results: @search_results, pagy: @pagy }
    end
  end
  # ...
end


class MyStrategy
  # ... 
  def search_all(search_phrase, doc_types)
     [find_docs(search_phrase, doc_types), SOMETHING_THAT_SAYS_WHICH_PATH]
  end
  # ...
end