Add whitelist mode (#11291)

app/models/domain_allow.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: domain_allows
+#
+#  id         :bigint(8)        not null, primary key
+#  domain     :string           default(""), not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class DomainAllow < ApplicationRecord
+  include DomainNormalizable
+
+  validates :domain, presence: true, uniqueness: true
+
+  scope :matches_domain, ->(value) { where(arel_table[:domain].matches("%#{value}%")) }
+
+  class << self
+    def allowed?(domain)
+      !rule_for(domain).nil?
+    end
+
+    def rule_for(domain)
+      return if domain.blank?
+
+      uri = Addressable::URI.new.tap { |u| u.host = domain.gsub(/[\/]/, '') }
+
+      find_by(domain: uri.normalized_host)
+    end
+  end
+end