Add honeypot fields and minimum fill-out time for sign-up form (#15276)

* Add honeypot fields to limit non-specialized spam

Add two honeypot fields: a fake website input and a fake password confirmation
one. The label/placeholder/aria-label tells not to fill them, and they are
hidden in CSS, so legitimate users should not fall into these.

This should cut down on some non-Mastodon-specific spambots.

* Require a 3 seconds delay before submitting the registration form

* Fix tests

* Move registration form time check to model validation

* Give people a chance to clear the honeypot fields

* Refactor honeypot translation strings

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/app/validators/registration_form_time_validator.rb b/app/validators/registration_form_time_validator.rb
new file mode 100644
index 000000000..ba7c7e6c6
--- /dev/null
+++ b/app/validators/registration_form_time_validator.rb
@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class RegistrationFormTimeValidator < ActiveModel::Validator
+  REGISTRATION_FORM_MIN_TIME = 3.seconds.freeze
+
+  def validate(user)
+    user.errors.add(:base, I18n.t('auth.too_fast')) if user.registration_form_time.present? && user.registration_form_time > REGISTRATION_FORM_MIN_TIME.ago
+  end
+end