Refactor preview environment loading (#14)

This allows us to load preview environments in the correct context:
e.g. on staging (where Rails.env.production? and !ENV['SERVE_TEST_UI'].blank?)
the preview should point to https://galc-api.ucblib.org/.

Routing is explicitly not enabled for the new preview controller/routes unless
there is a value for ENV['SERVE_TEST_UI'].

* address code review changes and fix test

* prefer assert_select over a regex parsing the rendered page

* Improve configuration injection; separate preview from AuthController

* ACAB includes rubocop 💎🚔

Author: anarchivist

Gemfile

@@ -36,6 +36,7 @@ end
 group :test do
   gem 'database_cleaner-active_record', '~> 2.0'
   gem 'factory_bot_rails'
+  gem 'rails-controller-testing'
   gem 'rspec', '~> 3.10'
   gem 'rspec_junit_formatter', '~> 0.5'
   gem 'rspec-rails', '~> 5.0'

Gemfile.lock

@@ -218,6 +218,10 @@ GEM
       activesupport (= 7.0.4.3)
       bundler (>= 1.15.0)
       railties (= 7.0.4.3)
+    rails-controller-testing (1.0.5)
+      actionpack (>= 5.0.1.rc1)
+      actionview (>= 5.0.1.rc1)
+      activesupport (>= 5.0.1.rc1)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
@@ -347,6 +351,7 @@ DEPENDENCIES
   puma (~> 5.0)
   rack-cors
   rails (~> 7.0.4)
+  rails-controller-testing
   ransack (~> 2.6)
   rspec (~> 3.10)
   rspec-rails (~> 5.0)

app/controllers/auth_controller.rb

@@ -3,16 +3,6 @@
 class AuthController < ApplicationController
   ERR_TICKET_MISMATCH = 'Ticket from callback URL parameter does not match credential from OmniAuth hash'.freeze
 
-  # Debug UI for staging, 404 Not Found for production
-  def index
-    raise Error::NotFoundError if ENV['SERVE_TEST_UI'].blank?
-
-    # TODO: Something more elegant
-    # Hack to get around the fact that API-only apps don't include an HTML renderer
-    pathname = Rails.root.join('public', 'index.html')
-    render xml: File.read(pathname), content_type: 'text/html'
-  end
-
   def callback
     logger.debug({ msg: 'Received omniauth callback', omniauth: auth_hash, params: params.to_unsafe_h })
 

app/controllers/preview/application_controller.rb

@@ -0,0 +1,3 @@
+module Preview
+  class ApplicationController < ActionController::Base; end
+end

app/controllers/preview/preview_controller.rb

@@ -0,0 +1,8 @@
+module Preview
+  class PreviewController < Preview::ApplicationController
+
+    def index
+      @api_url = ENV['GALC_API_URL'] || 'http://localhost:3000'
+    end
+  end
+end

public/index.html app/views/preview/preview/index.html.erbpublic/index.html renamed to app/views/preview/preview/index.html.erb

@@ -16,7 +16,7 @@
     <main>
         <div class="layout-content">
             <div class="region region-content">
-                <div id="galc-app" data-api-base-url="http://localhost:3000" class="block-views"></div>
+                <div id="galc-app" data-api-base-url="<%= @api_url %>" class="block-views"></div>
             </div>
         </div>
     </main>

config/routes.rb

@@ -1,10 +1,15 @@
 Rails.application.routes.draw do
-  root to: 'auth#index'
 
   direct(:login) { '/auth/calnet' } # convenience to provide login_url helper
   get '/logout', to: 'auth#logout', as: :logout
   get '/auth/:provider/callback', to: 'auth#callback', as: :omniauth_callback
 
+  scope module: 'preview' do
+    constraints(->(_) { ENV['SERVE_TEST_UI'].present? }) do
+      root to: 'preview#index', as: :preview
+    end
+  end
+
   defaults format: :jsonapi do
     constraints(->(req) { req.format == :jsonapi }) do
       resources :closures

docker-compose.yml

@@ -8,6 +8,7 @@ services:
       - db
     environment:
       - SERVE_TEST_UI=${SERVE_TEST_UI:-true}
+      - GALC_API_URL=${GALC_API_URL:-http://localhost:3000}
     init: true
     networks:
       default:

spec/requests/auth_spec.rb

@@ -39,22 +39,6 @@
   # ------------------------------------------------------------
   # Tests
 
-  describe 'GET /' do
-    it 'returns 404 Not Found' do
-      allow(ENV).to receive(:[]).with('SERVE_TEST_UI').and_return(nil)
-      get root_path
-      expect(response).to have_http_status(:not_found)
-    end
-
-    it 'serves a test UI in staging' do
-      allow(ENV).to receive(:[]).with('SERVE_TEST_UI').and_return(true)
-
-      get root_path
-      expect(response).to have_http_status(:ok)
-      expect(response.content_type).to start_with('text/html')
-    end
-  end
-
   describe 'GET /auth/calnet' do
     # See https://github.com/omniauth/omniauth/wiki/Resolving-CVE-2015-9284
     it 'is disallowed' do

spec/requests/preview/preview_spec.rb

@@ -0,0 +1,32 @@
+require 'rails_helper'
+
+RSpec.describe Preview::PreviewController, type: :request do
+  describe 'GET /' do
+    context 'with the preview environment enabled' do
+      before do
+        allow(ENV).to receive(:[]).with('SERVE_TEST_UI').and_return(true)
+      end
+
+      it 'shows a test UI in when SERVE_TEST_UI is true' do
+        allow(ENV).to receive(:[]).with('GALC_API_URL').and_return('https://galc.biz')
+        get preview_path
+        expect(response).to have_http_status(:ok)
+        expect(response.content_type).to start_with('text/html')
+      end
+
+      context 'sets the API URL correctly' do
+        it 'sets the url when GALC_API_URL is present' do
+          allow(ENV).to receive(:[]).with('GALC_API_URL').and_return('https://galc.biz')
+          get preview_path
+          expect(assigns(:api_url)).to eq('https://galc.biz')
+        end
+
+        it 'sets the API URL when GALC_API_URL is not present' do
+          allow(ENV).to receive(:[]).with('GALC_API_URL').and_return(nil)
+          get preview_path
+          expect(assigns(:api_url)).to eq('http://localhost:3000')
+        end
+      end
+    end
+  end
+end