rails_call_another_controller_action.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", "6.0.0"
end

require "rack/test"
require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  config.hosts << "example.org"
  config.session_store :cookie_store, key: "cookie_store_key"
  secrets.secret_key_base = "secret_key_base"

  config.logger = Logger.new($stdout)
  Rails.logger  = config.logger

  routes.draw do
    get "/items/:id" => "items#show"
  end
end

class ItemsController < ActionController::Base
  include Rails.application.routes.url_helpers

  def show
    request.params[:item_id] = request.params[:id]
    ac = AnotherController.new
    res = ac.dispatch(:get, request, response)
    item_id = ac.instance_variable_get(:@item_id)
    puts "instance var item_id: #{item_id}"
    render json: { msg: "OK", body: JSON.parse(res[2].body) }, status: 200
  end
end

class AnotherController < ActionController::Base
  include Rails.application.routes.url_helpers
  before_action :set_item_id

  def get
    item = {
      "1" => "hello",
      "2" => "world",
    }[@item_id]

    render json: { item: item }, status: 200
  end
  private
  def set_item_id
    @item_id = params.require(:item_id)
  end
end

require "minitest/autorun"

class BugTest < Minitest::Test
  include Rack::Test::Methods

  def test_returns_success
    get "/items/1"
    assert last_response.ok?
    assert last_response.body == '{"msg":"OK","body":{"item":"hello"}}', last_response.body

    get "/items/2"
    assert last_response.ok?
    assert last_response.body == '{"msg":"OK","body":{"item":"world"}}', last_response.body

    get "/items/3"
    assert last_response.ok?
    assert last_response.body == '{"msg":"OK","body":{"item":null}}', last_response.body
  end

  private
    def app
      Rails.application
    end
end