Rails 3 How to assign the value to nested attributes before calling save in update action

I am using Rails 3.0.9 and Ruby 1.9.2

Models associations are

document.rb
    has_many :sections
    accepts_nested_attributes_for :sections, :allow_destroy =3D> :true,
          :reject_if =3D> proc { |attrs| attrs.all? { |k, v| v.blank? } }=


section.rb
    belongs_to :document
    has_many :paragraphs, :dependent =3D> :destroy
    has_many :contents :through =3D> :paragraphs
    validates :user_id, :presence =3D>  { :message =3D> "Must be filled" =
}

paragraph.rb
    attr_accessible :user_id, :section_id, :content_id
    belongs_to :section
    belongs_to :content
    validates :user_id, :section, :content, :presence =3D>  { :message =3D=
>
                                                  "Must be filled" }

paragraphs table just like a intermediate table for sections and
contents and I want to save records in documents, sections and
paragraphs table using single form submission.

_form.html.erb

    <%=3D form_for @document, :validate =3D> true do |f| %>
     <%=3D f.error_messages %>
     <div><%=3D f.text_field :name %></div>

     <% f.fields_for :sections do |builder| %>
       <div><%=3D builder.text_field :name %></div>
       <div>
        <%=3D builder.select :content_ids,
         Content.all.collect {|p| [ p.name, p.id ] },
         {:prompt =3D> "Please Select"}, {:class =3D> "nhs_select",
            :multiple =3D> true}  %>
        </div>
        <% end %>
        <%=3D f.submit :submit%>
   <% end %>


Example parameters when submiting the form
    {"document"=3D>{"name"=3D>"sdf",
"sections_attributes"=3D>{"0"=3D>{"name"=3D>"sdf", "description"=3D>"sdf"=
,
"_destroy"=3D>"0", "content_ids" =3D> ["1", "2"]}}, "commit"=3D>"Create
Document"}

In additionally, I should need to update current_user's id to user_id
column of paragraphs table.

def create
    @document =3D Document.new
    @document.attributes =3D params[:document]
    @document.sections.each {|section|
      section.user_id =3D current_user.id
      section.paragraphs.each {|paragraph| paragraph.user_id =3D
current_user.id}
    }
    if @document.save!
      # success
    else
      render :action =3D> 'new'
    end
end

Problem 1:

At first, I submit the form, rails render new form without error message
even I have implemented code to display error messages.

then again clicked submit button, action goes to update method. But it
should go to new action.

I inspected in console, the inserted records were rollbacked but still
the ID is retain in object.

Example: <form id=3D"edit_document_6" class=3D"edit_document" method=3D"p=
ost"
action=3D"/documents/6" accept-charset=3D"UTF-8">

Problem 2:

Documentation said that the changes are not saved to the database when
assigning the attributes as like user.attributes =3D {:name =3D> =E2=80=9C=
Rob=E2=80=9D}.

but my case validation is triggered when assigning the attributes so I
can't assign the value to user_id column in paragraph object before
calling save method

@document.attributes =3D {"sections_attributes"=3D>{"0"=3D>{"name"=3D>"sd=
f",
"content_ids" =3D> ["1", "2"]}}
or
section =3D Section.first
section.attributes =3D {"content_ids" =3D> ["1", "2"]}

How to assign the value to user_id in paragraph object before calling
save method

-- =

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