What is the best way to add a check for accepting terms of use in a rails app?
I can't seem to get validates_acceptance_of working quite right. I added a bool to my user model (was that necessary?). And then have a checkbox that returns either true/false.
I feel like I'm just making a silly little mistake. Any ideas?
This is a working solution for Rails-6.1 (I18n) + Devise-4.8.0 + SimpleForm. No need to add a column in the "users" table in DB.
View
<% label_str = t('read_html', mylink: link_to(t('terms'), '/a/b/c')) %>
<%= f.input :terms_of_service, label: label_str, as: :boolean, checked: false %>
Or, if you use Indo-European languages only, you can make it a little more simple, like:
label_str = (t('agree_html')+link_to(t('terms'), '/a/b/c')+'.').html_safe
/app/models/user.rb
attr_accessor :terms_of_service
validates_acceptance_of :terms_of_service, on: :create
validates_presence_of :terms_of_service, on: :create
/app/controllers/application_controller.rb
Devise::ParameterSanitizer::DEFAULT_PERMITTED_ATTRIBUTES[:sign_up] << :terms_of_service
# see /vendor/bundle/ruby/*/gems/devise-*/lib/devise/parameter_sanitizer.rb
In the User model, on: create guarantees it is read only in creation. If you need to reevaluate the condition in updating, too, specify it accordingly, like on: %i(create update).
In the User model, I add validates_presence_of to play safe. The reason is, validates_acceptance_of will not be executed when the parameter terms_of_service is nil, in which case validates_presence_of will catch it and set an error. Admittedly, if the data are always submitted via the web-interface you have built AND your implementation is working perfectly, the value should be always either true or false and never be nil. So, validates_presence_of should not be necessary in this sense. It does no harm, though (except you'd need to be a little careful in manual user creation, bypassing the web-interface, such as from the Console).
The last one is neccesary for use with Devise for the same reason as in the answer by @vladCovaliov; that is, to prevent Devise from sanitizing your custom parameter, which is not a column in the database table. The one-liner in the example above can be stated in any files as long as you are sure it is read at the run-time and after Devise Ruby code. application_controller.rb is one of the sure places (though I guess there is a better-fitting place). Make sure the sentence is put out of the class ApplicationController block.