How to validate form fields without a model?

Question

Ruby on Rails

But since there is no model, I don't even know how to implement it. Here is the controller code:
class ZamsController < ApplicationController
def index
@clue = params[:name] + "." + params[:city] + "." + params[:phone1] + "." + params[:email]
ZamsMailer.zayavka(@clue).deliver
redirect_to root_path, success: 'Request sent successfully!'
end
end
Is there any other way to implement validation?

Answer 1

Read about the FormObject pattern
https://robots.thoughtbot.com/activemodel-form-objects