rails 3.1 has_many :through extra field in join model

Question

i'm trying to solve has_many :through association with additional text_field in join model.None of the existing answers do the trick for me.

I have three models:

class Partner
    has_many :prices
    has_many :services, :through => :prices
    accept_nested_attributes_for :prices
end


class Service
    has_many :prices
    has_many :partners, :through => :prices
end


class Price
    belongs_to :service
    belongs_to :partner
end

Prices table looks like this:

    id
    partner_id
    service_id
    price

I need to enter price for every selected service.

View looks like this:

 <%= form_for(@partner, :url => save_services_path(@partner.id), :remote => true) do |f| %>
  <table>
    <% @services.in_groups_of(4, false) do |services| %>
      <tr>
        <% services.each do |service| %>
          <td>
        <%= check_box_tag "partner[service_ids][]", service.id, @partner.services.include?(service) %> 
        <%= service.name %>
        <%= f.fields_for :prices do |p| %>
          <%= p.text_field :price %>
        <% end %>
          </td>
        <% end %>
      </tr>
    <% end %>
  </table>
<% end %>

Checkbox works fine, but i'm unable to update price for service. I believe the problem is in nested form syntax...i've tried many different combinations but non worked.

Thanks in advance!

UPDATE:

controller action:

def save_services
  @partner = Partner.find(params[:id])
  @partner.update_attributes(params[:partner]
end

log:

Started PUT "/partners/save_services/337" for 
Processing by PartnersController#save_services as JS
  Parameters: {"utf8"=>"â", "authenticity_token"=>"xxx", "partner"=>{"service_ids"=>["20", "24"]}, "commit"=>"Save", "id"=>"337"}

Answer 1

Why do you have this?

:url => save_services_path(@partner.id)

in your form_for? you're creating form with @partner, but saving with services.. try

<%= form_for(@partner, :url => {:action => 'update'}, :remote => true) do |f| %>

or post your params from log