Rails ActiveModel::Model Example, an alternative to ActiveRecord when you don't need the DB

contact_request.rb

# NOTE: this a partial copy of some working code from a working Rails app
# *However* it hasn't been tested on it's own, shown here as an example of
# using ActiveModel::Model as an alternative to ActiveRecord when you don't 
# need the DB

class ContactRequest
  include ActiveModel::Model

  def self.define_sanitized_attr(attr)
    define_method(attr) do
      instance_variable_get("@#{attr}")
    end
    define_method("#{attr}=") do |val|
      val = ActionView::Base.full_sanitizer.sanitize(val)
      instance_variable_set("@#{attr}", val)
    end
  end

  
  ATTRS = %i[name email email_confirmation phone message country_code].freeze
  ATTRS.each do |attr|
    define_sanitized_attr attr
  end

  
  def self.contact_request_from_params(params)
    contact_request = ContactRequest.new
    Rails.logger.info("contact_request has following instance variables #{contact_request.instance_variables}")
    ATTRS.each do |attr_name|
      prop_name = "@#{attr_name}".to_sym
      Rails.logger.info("setting attribute #{attr_name} to prop #{prop_name} = value #{params[attr_name]}")
      contact_request.instance_variable_set(prop_name, params[attr_name]) if params.key?(attr_name)
    end
    contact_request
  end

  validates :name, :email, :email_confirmation, :message, :country_code, presence: { message: "%{attribute} must be given please" }
  validates :email, confirmation: { case_sensitive: false }
  validates_format_of :email, with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
  validates :name, length: { minimum: 2, too_short: "Name must be at least %{count} characters" }
  validates :message, length: { maximum: 2000, too_long: "%{count} characters is the maximum allowed."}


  def persisted?
    true
  end

  def id
    nil
  end

  def to_hash
    hash = {}
    ATTRS.each do |attr_name|
      prop_name = "@#{attr_name}".to_sym
      if value = instance_variable_get(prop_name)
        hash[attr_name.to_s] = value
      end
    end
    hash
  end

  def to_param
    if persisted?
      to_hash
    else
      nil
    end
  end

end