nested attributes and initialization

I have a user model that has a few different roles (say a client and
an agent) The agent has some extra relationships not found in a
client role (has_one :agent_profile, for instance)

I have an edit_profile action for an agent that has these nested
attributes in the form and the model
accepts_nested_attributes_for :agent_profile:

<% form_for @agent, :url => agent_path(@agent) do |form| %>
  <%= form.label :name %>
  <%= form.text_field :name %>

  <% form.fields_for :agent_profile do |a_form| %>
  <%= a_form.label :website, "Website Address:"%>
  <%= a_form.text_field :website %>
  <% end %>
<% end %>

If an agent_profile object isn't present however, when an agent edits
their profile, they get the:

ActionView::TemplateError (You have a nil object when you didn't
expect it!
The error occurred while evaluating nil.new_record?

Is it common that I would have an after_initialize method such as:

  def after_initialize
    self.build_agent_profile if self.role_name == "agent" && !

Seems a bit odd to me to do this for all relationships I have that
accept nested attributes, but I can't really think of a better way. I
also don't want to split the User model into two models because agents
and clients log in/sign up in the same way.

Hello Bradley,

Please check on this railscast

This is a better way to handle roles in your case.

Rodrigo Dellacqua
IBM - IGF Project Manager
“Communication is the key”