FIX: validate automatic membership email domains

app/models/group.rb

@@ -21,6 +21,7 @@ class Group < ActiveRecord::Base
 
   validate :name_format_validator
   validates_uniqueness_of :name, case_sensitive: false
+  validate :automatic_membership_email_domains_format_validator
 
   AUTO_GROUPS = {
     :everyone => 0,
@@ -290,6 +291,18 @@ class Group < ActiveRecord::Base
       UsernameValidator.perform_validation(self, 'name')
     end
 
+    def automatic_membership_email_domains_format_validator
+      return if self.automatic_membership_email_domains.blank?
+
+      domains = self.automatic_membership_email_domains.split("|")
+      domains.each do |domain|
+        domain.sub!(/^https?:\/\//, '')
+        domain.sub!(/\/.*$/, '')
+        self.errors.add :base, (I18n.t('groups.errors.invalid_domain', domain: domain)) unless domain =~ /\A[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?\Z/i
+      end
+      self.automatic_membership_email_domains = domains.join("|")
+    end
+
     # hack around AR
     def destroy_deletions
       if @deletions

config/locales/server.en.yml

@@ -196,6 +196,7 @@ en:
     errors:
       can_not_modify_automatic: "You can not modify an automatic group"
       member_already_exist: "'%{username}' is already a member of this group."
+      invalid_domain: "'%{domain}' is not a valid domain."
     default_names:
       everyone: "everyone"
       admins: "admins"

spec/models/group_spec.rb

@@ -33,6 +33,16 @@ describe Group do
       group.name = 'This_Is_A_Name'
       expect(group.valid?).to eq false
     end
+
+    it "is invalid for poorly formatted domains" do
+      group.automatic_membership_email_domains = "wikipedia.org|*@example.com"
+      expect(group.valid?).to eq false
+    end
+
+    it "is valid for proper domains" do
+      group.automatic_membership_email_domains = "discourse.org|wikipedia.org"
+      expect(group.valid?).to eq true
+    end
   end
 
   def real_admins