Set default URL host

Setting the default host resolves:

    Missing host to link to! Please provide the :host parameter, set
    default_url_options[:host], or set :only_path to true

Configuring RSpec to use the default host resolves:

    Expected response to be a redirect to <http://test.host/…>
    but was a redirect to <http://localhost/…>.

config/environments/development.rb

@@ -54,8 +54,10 @@ Rails.application.configure do
   # Annotate rendered view with file names.
   # config.action_view.annotate_rendered_view_with_filenames = true
 
-  # Set the detault url for action mailer
-  config.action_mailer.default_url_options = { host: ENV.fetch('OSEM_HOSTNAME', 'localhost:3000') }
+  # Provide a default host for URLs
+  Rails.application.routes.default_url_options[:host] = ENV.fetch('OSEM_HOSTNAME', 'localhost:3000')
+  config.action_controller.default_url_options = Rails.application.routes.default_url_options
+  config.action_mailer.default_url_options = Rails.application.routes.default_url_options
 
   # Access all mails sent at http://localhost:3000/letter_opener
   config.action_mailer.delivery_method = :letter_opener

config/environments/production.rb

@@ -73,7 +73,12 @@ Rails.application.configure do
     config.logger    = ActiveSupport::TaggedLogging.new(logger)
   end
 
-  config.action_mailer.default_url_options = { host: ENV.fetch('OSEM_HOSTNAME', 'localhost:3000') }
+  # Provide a default host for URLs
+  Rails.application.routes.default_url_options[:host] = ENV.fetch('OSEM_HOSTNAME', 'localhost:3000')
+  config.action_controller.default_url_options = Rails.application.routes.default_url_options
+  config.action_mailer.default_url_options = Rails.application.routes.default_url_options
+
+  # Configure outgoing mail
   config.action_mailer.smtp_settings = {
     address:              ENV.fetch('OSEM_SMTP_ADDRESS', 'localhost'),
     port:                 ENV.fetch('OSEM_SMTP_PORT', 25),

config/environments/test.rb

@@ -43,8 +43,12 @@ Rails.application.configure do
   # Tell Active Support which deprecation messages to disallow.
   config.active_support.disallowed_deprecation_warnings = []
 
-  # Set the detault url for action mailer
-  config.action_mailer.default_url_options = { host: 'localhost:3000' }
+  # Provide a default host for URLs
+  Rails.application.routes.default_url_options[:host] = 'localhost:3000'
+  config.action_controller.default_url_options = Rails.application.routes.default_url_options
+  config.action_mailer.default_url_options = Rails.application.routes.default_url_options
+
+  # Configure outgoing mail
   config.action_mailer.delivery_method = :test
 
   config.after_initialize do