chore: extract whitelabel detection into middleware

app/controllers/admin/application_controller.rb

@@ -6,7 +6,6 @@
 # you're free to overwrite the RESTful controller actions.
 module Admin
   class ApplicationController < Administrate::ApplicationController
-    include WhitelabelDetection
     include UserHandling
     include LocaleDetection
     include TimeZoneDetection
@@ -26,7 +25,6 @@ class ApplicationController < Administrate::ApplicationController
     private
 
     def setup
-      switch_label
       switch_locale
       switch_time_zone
     end

app/controllers/application_controller.rb

@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 class ApplicationController < ActionController::Base
-  include WhitelabelDetection
   include LocaleDetection
   include TimeZoneDetection
   include UserHandling
@@ -23,7 +22,6 @@ class ApplicationController < ActionController::Base
   protected
 
   def setup
-    switch_label
     switch_locale
     switch_time_zone
   end

app/controllers/super_admin/application_controller.rb

@@ -6,7 +6,6 @@
 # you're free to overwrite the RESTful controller actions.
 module SuperAdmin
   class ApplicationController < Administrate::ApplicationController
-    include WhitelabelDetection
     include UserHandling
     include LocaleDetection
     include TimeZoneDetection
@@ -26,7 +25,6 @@ class ApplicationController < Administrate::ApplicationController
     private
 
     def setup
-      switch_label
       switch_locale
       switch_time_zone
     end

app/lib/whitelabel_detection_middleware.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class WhitelabelDetectionMiddleware
+  def initialize(app)
+    @app = app
+  end
+
+  def call(env)
+    Whitelabel.reset!
+    request = ActionDispatch::Request.new(env)
+    Whitelabel.label = detect_label(request)
+    @app.call(env)
+  end
+
+  private
+
+  def detect_label(request)
+    Whitelabel.label_for(request.subdomains.first).tap { |label| return label unless label.nil? }
+
+    Whitelabel.labels.find do |label|
+      label.domains&.any? do |custom_domain|
+        return label if request.host =~ /#{custom_domain}/
+      end
+    end
+
+    Whitelabel.labels.first
+  end
+end

config/initializers/whitelabel.rb

@@ -1,3 +1,5 @@
 Usergroup.initialize!
 
 I18n.extend WhitelabelTranslation
+
+Rails.application.config.middleware.insert_before OmniAuth::Builder, WhitelabelDetectionMiddleware

spec/lib/whitelabel_detection_middleware_spec.rb

@@ -0,0 +1,29 @@
+require 'spec_helper'
+require 'whitelabel_detection_middleware'
+
+describe WhitelabelDetectionMiddleware do
+  subject(:middleware) { described_class.new(dummy_app) }
+
+  let(:dummy_app) { ->(_env) { response } }
+  let(:host) { 'localhost' }
+  let(:rack_env) { { 'HTTP_HOST' => host } }
+  let(:response) { [418, { 'Content-Type' => 'text/plain' }, ['418 No coffee here.']] }
+
+  before { middleware.call(rack_env) }
+
+  {
+    'hamburg.onruby.de' => 'hamburg',
+    'onruby.eu' => 'hamburg',
+    'dresdenrb.onruby.de' => 'dresdenrb',
+    'tallinn.ruby.ee' => 'tallinn_rug',
+    'www.rug-b.de' => 'berlin',
+  }.each do |host, label|
+    context "with host '#{host}'" do
+      let(:host) { host }
+
+      it "uses Whitelabel '#{label}'" do
+        expect(Whitelabel[:label_id]).to eq(label)
+      end
+    end
+  end
+end