Rails + MongoMapper + EmbeddedDocument form help

Question

I am working on a pretty simple web application (famous last words) and am working with Rails 2.3.5 + MongoMapper 0.7.2 and using embedded documents. I have two questions to ask:

First, are there any example applications out there using Rails + MongoMapper + EmbeddedDocument? Preferably on GitHub or some other similar site so that I can take a look at the source and see where I am supposed to head? If not ...

... what is the best way to approach this task? How would I go about creating a form to handle an embedded document.

What I am attempting to do is add addresses to users. I can toss up the two models in question if you would like.

Thanks for the help!

Answer 1

Here's the basic approach I took in one of my apps. Problem has many answers - problem is a document, answer is an embedded document. You can use the "add answer" link to generate another answer field, and the "remove" link to delete one.

_form.html.erb:

<% form_for @problem do |f| %>
  <%= f.error_messages %>

  <p>
    <%= f.label :content %><br />
    <%= f.text_area :content, :size => '50x7' %>
  </p>

  ...etc...

  <%= add_answer_link "(add answer)" %>
  <div id="answers">
    <%= render :partial => 'answer', :collection => @problem.answers %>
  </div>

  <p><%= f.submit "Submit" %></p>
<% end %>

_answer.html.erb:

<div class="answer">
  <% fields_for 'problem[answers]', answer, :index => nil do |f| -%>
    <%= f.label :content, "Answer #{answer.id}:" %>
    <%= f.text_field :content, :size => 50 %>
    <%= link_to_function "(remove)", "$(this).up('.answer').remove()" %>
  <% end -%>
</div>

problems_helper.rb

module ProblemsHelper
  def add_answer_link(name)
    link_to_function name do |page|
      page.insert_html :bottom, "answers", :partial => 'answer', :object => Answer.new
    end
  end
end

I cut out a couple minor bits of the implementation, but that should work.