Rails - Aug 2009 - has_many :through, multi model form unable to save new child

I am totally unable to create a new child in a has_many :through multi
model form using nested_attributes for an existing grandparent.

Sorry, that sounds quite a mouth full.

Basically I am editing an existing user that has many
administrator_addresses through an administrator association.
If I create a new address for the user I get various errors related to
the association between users(grandparent) and
administrator_addresses(grandchild) and I''m wondering how the new
address record(grandchild) get''s the administrator (parent)
information?

Grandparent <- Parent <- child
Grandparent has_many :grand_children, :through => :parent, :source =>
:child

If the child validates_presence_of :parent_id I get an error parent must
not be blank.

If I don''t validate the parent id I receive an error stating

    Cannot modify association ''User#administrator_addresses''
because the
source reflection class ''Address'' is associated to
''Administrator'' via
:has_many.

which makes sense if the parent_id has not been passed to the params
hash for the create method.

So how to set the parent ID on the child on a has_many :through multi
model form?

I''m wondering if I have missed something obvious.

Models

   class User < ActiveRecord::Base

     named_scope :find_administrators, :joins => :administrator

     has_one :administrator,
             :dependent => :destroy

     has_many :administrator_addresses,
              :through => :administrator,
              :source => :addresses,
              :dependent => :destroy

     accepts_nested_attributes_for :administrator_addresses,
:allow_destroy => true
   ...
   end

   class Administrator < UserRole
     belongs_to :user
     has_one :site_contact, :foreign_key => :user_role_id
     has_many :addresses, :foreign_key => :contact_id, :dependent =>
:destroy

   end

   class Address < ActiveRecord::Base

     belongs_to :administrator, :foreign_key => :contact_id

     validates_presence_of :contact_id

     validates_presence_of :house

   end

   class UserRole < ActiveRecord::Base
   end

The link helper to build the nested form (slightly different from you
usage)

     def add_address_link(form_builder)
       link_to_function ''New address'' do |page|
         form_builder.fields_for :administrator_addresses,
                                 Address.new,
                                 :child_index =>
''NEW_RECORD'' do |f|
           html = render(:partial => ''address_form'',
:locals => { :f =>
f })
           page <<
"jQuery(''#maintenance_form'').replaceWith(''#{escape_javascript(html)}''.replace(/NEW_RECORD/g,
new Date().getTime()))"
         end
        end
     end

The _address_form.html.erb

    <fieldset>
      <legend>Details...</legend>
       <p>
         House name/number<br />
         <%= f.text_field :house %>
       </p>
       <p>
         Street<br />
         <%= f.text_field :street %>
       </p>
       <p>
         Town<br />
         <%= f.text_field :town %>
       </p>
       <p>
         city<br />
         <%= f.text_field :city %>
       </p>
       <p>
         Postcode<br />
         <%= f.text_field :postcode %>
       </p>
     <%= link_to_function ''Done'' %>
   </fieldset>

The params hash shows

    {"user"=>{"name"=>"test2",
    "public_name"=>"Test 2",
    "password_confirmation"=>"",
   
"administrator_addresses_attributes"=>{"1249586125635"=>{"city"=>"fff",
    "postcode"=>"fff",
    "house"=>"fff",
    "street"=>"fff",
    "town"=>"ffff"}},
    "password"=>""},
    "commit"=>"Update",
    "_method"=>"put",
   
"authenticity_token"=>"rKa5WGzAcoSDRgBtTA1/RSFp5k4pKQhTCWp1fTRiq6o=",
    "id"=>"1"}

The update method in the user controller

      def update
        logger.debug("#### update params = #{params}")
        @user = User.find(params[:id])

        respond_to do |format|
          if @user.update_attributes(params[:user])
            flash[:notice] = "#{show_user_type} was successfully
updated."
            format.html { redirect_to([:admin, @user]) }
            format.xml  { head :ok }
          else
            format.html { render :action => "edit" }
            format.xml  { render :xml => @user.errors, :status =>
:unprocessable_entity }
          end
        end
      end

Any ideas would be really cool!
Thanks
-- 
Posted via http://www.ruby-forum.com/.

Further testing shows that if I use a hidden contact_id field in the 
address form the contact_id gets passed to the params hash as I would 
expect but I still get the

Cannot modify association ''User#administrator_addresses''
because the
source reflection class ''Address'' is associated to
''Administrator'' via
:has_many.

error! I''m totally stumped and this is becoming rather critical so if 
anyone has any work arounds I''d appreciate it.
-- 
Posted via http://www.ruby-forum.com/.

James West wrote:
> Further testing shows that if I use a hidden contact_id field in the 
> address form the contact_id gets passed to the params hash as I would 
> expect but I still get the
> 

You either have to change:

     has_one :administrator,
             :dependent => :destroy



to:
     has_many :administrators,
             :dependent => :destroy


or remove the administrator_addresses association and do this..

def administrator_addresses
   administrator.addresses
end

your through relation should go through a ''has_many'' and not a
''has_one''..

hth

ilan



-- 
Posted via http://www.ruby-forum.com/.

Ilan Berci wrote:
> James West wrote:
>> Further testing shows that if I use a hidden contact_id field in the 
>> address form the contact_id gets passed to the params hash as I would 
>> expect but I still get the
>> 
> 
> 
> You either have to change:
> 
>      has_one :administrator,
>              :dependent => :destroy
> 
> 
> 
> to:
>      has_many :administrators,
>              :dependent => :destroy
> 
> 
> or remove the administrator_addresses association and do this..
> 
> def administrator_addresses
>    administrator.addresses
> end
> 
> your through relation should go through a ''has_many'' and
not a
> ''has_one''..
> 
> hth
> 
> ilan
Thank you for your reply,

I have changed my association because what you say makes total sense 
however I''m still getting the same error.
I''m starting to think that the accepts_nested_attributes is broken.

I now have in my models.
class User < ActiveRecord::Base

  named_scope :find_administrators, :joins => :administrator

  has_one :administrator,
          :dependent => :destroy

  has_many :user_roles,
           :dependent => :destroy

  has_many :addresses,
           :through => :user_roles,
           :source => :addresses,
           :foreign_key => :contact_id,
           :dependent => :destroy

  accepts_nested_attributes_for :addresses, :allow_destroy => true

...
end

class UserRole < ActiveRecord::Base

  has_many :addresses, :foreign_key => :contact_id,
           :dependent => :destroy

  has_many :emails, :foreign_key => :contact_id,
          :dependent => :destroy

  belongs_to :user

  accepts_nested_attributes_for :addresses, :allow_destroy => true

end

class Address < ActiveRecord::Base

  belongs_to :user_role, :foreign_key => :contact_id

  validates_presence_of :contact_id

  validates_presence_of :house

end

class Administrator < UserRole
  #To do - Move this to a boolean flag on the user_role table.
  has_one :site_contact, :foreign_key => :user_role_id
end

Relevant controller methods
class Admin::UsersController < Admin::HomeController

  # GET /users/1/edit
  def edit
    @user = User.find(params[:id])
  end

  # PUT /users/1
  # PUT /users/1.xml
  def update
    logger.debug("#### update params = #{params}")
    @user = User.find(params[:id])

    respond_to do |format|
      if @user.update_attributes(params[:user])
        flash[:notice] = "#{show_user_type} was successfully updated."
        format.html { redirect_to([:admin, @user]) }
        format.xml  { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml  { render :xml => @user.errors, :status => 
:unprocessable_entity }
      end
    end
  end

Helper methods
  #
  # Support methods for nested forms
  #
  def link_to_toggle_child_list(div_to_toggle, link_text)
    link_to_function link_text do |page|
      page <<
"jQuery(''#{div_to_toggle}).toggle(''slow'')"
    end
  end

  def add_address_link(form_builder)
    link_to_function ''New address'' do |page|
      form_builder.fields_for :addresses,
                              Address.new,
                              :child_index => ''NEW_RECORD''
do |f|
        html = render(:partial => ''address_form'', :locals
=> { :f => f
})
        page << 
"jQuery(''#maintenance_form'').replaceWith(''#{escape_javascript(html)}''.replace(/NEW_RECORD/g,
new Date().getTime()))"
      end
    end
  end
end

Views
_form.html.erb

<%= f.error_messages -%>
<div class="admin-form">
  <fieldset>
    <legend><%= show_user_type %></legend>
    <p>
      <%= f.label :public_name -%>:
      <%= f.text_field :public_name -%>
    </p>
    <p>
      <%= f.label :name -%>:
      <%= f.text_field :name -%>
    </p>
    <p>
      <%= f.label :password, ''Password'' -%>:
      <%= f.password_field :password, :size => 40-%>
    </p>
    <p>
      <%= f.label :password_confirmation, "confirm" -%>:
      <%= f.password_field :password_confirmation, :size => 40-%>
    </p>
  </fieldset>
</div>
<%= link_to_function "Show/Hide addresses", {:id =>
"toggle_children"}%>

div id ="address_list">
  <%= add_address_link(f) %>
  <%= show_address_list(@user) %>
</div>
<div id ="maintenance_form">
</div>

_address_form.html.erb

<%= f.hidden_field :contact_id%>
<fieldset>
  <legend>Details...</legend>
    <p>
      House name/number<br />
      <%= f.text_field :house %>
    </p>
    <p>
      Street<br />
      <%= f.text_field :street %>
    </p>
    <p>
      Town<br />
      <%= f.text_field :town %>
    </p>
    <p>
      city<br />
      <%= f.text_field :city %>
    </p>
    <p>
      Postcode<br />
      <%= f.text_field :postcode %>
    </p>
  <%= link_to_function ''Done'' %>
</fieldset>
-- 
Posted via http://www.ruby-forum.com/.

James West wrote:
Sorry, I ommited to post the actual error which is now

Cannot modify association ''User#addresses'' because the source
reflection
class ''Address'' is associated to ''UserRole''
via :has_many.
-- 
Posted via http://www.ruby-forum.com/.

James West wrote:
> James West wrote:
> Sorry, I ommited to post the actual error which is now
> 
> Cannot modify association ''User#addresses'' because the
source reflection
> class ''Address'' is associated to
''UserRole'' via :has_many.
Further investigation shows that the address record seems to have the 
correct SQL being generated for it.
I just updated Rails from 2.3.2 to 2.3.3 to see if that made a 
difference but this has had no effect.

Processing Admin::UsersController#update (for 127.0.0.1 at 2009-08-08 
07:37:27) [PUT]
  Parameters: {"user"=>{"name"=>"test2",
"public_name"=>"Test 2",
"addresses_attributes"=>{"1249713438151"=>{"city"=>"ccc",
"postcode"=>"ccc", "house"=>"ccc",
"town"=>"ccc", "street"=>"ccc"}},
"password_confirmation"=>"",
"password"=>""},
"commit"=>"Update",
"authenticity_token"=>"xO3gOpJcO08UGEzEtifnCIKqEOhwtDaz0UkM7X7aAQY=",
"id"=>"1"}
   [4;36;1mUser Load (0.0ms) [0m    [0;1mSELECT * FROM "users" WHERE 
("users"."id" = 1) LIMIT 1 [0m
   [4;35;1mTheme Load (0.0ms) [0m    [0mSELECT * FROM "themes" WHERE 
("themes"."active" = ''t'') LIMIT 1 [0m

ActiveRecord::HasManyThroughCantAssociateThroughHasManyReflection 
(Cannot modify association ''User#addresses'' because the source
reflection class ''Address'' is associated to
''UserRole'' via :has_many.):
  app/controllers/admin/users_controller.rb:72:in `update''
  app/controllers/admin/users_controller.rb:71:in `update''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in 
`service''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in 
`run''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:173:in 
`start_thread''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:162:in 
`start''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:162:in 
`start_thread''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:95:in 
`start''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:92:in 
`each''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:92:in 
`start''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:23:in 
`start''
  C:/Development/InstantRails/ruby/lib/ruby/1.8/webrick/server.rb:82:in 
`start''

Rendered rescues/_trace (484.0ms)
Rendered rescues/_request_and_response (0.0ms)
Rendering rescues/layout (internal_server_error)
-- 
Posted via http://www.ruby-forum.com/.

OK this is a Rails bug.
I have done extensive testing now and am able to prove that the code 
works on a has many but has_many :through fails.
I''ll report it as a bug if someone can tell me how?

Thanks

James
-- 
Posted via http://www.ruby-forum.com/.