ruby on rails - presenting many to many relation - ruby-on-rails

Question

I have recipe and ingredient in a many to many relation.
I have defined the following commands in my presentation.
<div>
<%= render :partial => 'ingredients/form',
:locals => {:form => recipe_form} %>
</div>
the partial begins with
<%= form_for(#ingredient) do |ingredient_form| %>
but received #ingredient nill.
Then I tried
<%= recipe_form.fields_for :ingredients do |builder| %>
<%= render 'ingredient_fields', f: builder %>
<% end %>
where my render was
<p class="fields">
<%= f.text_field :name %>
<%= f.hidden_field :_destroy %>
</p>
but nothing was printed.
then I tried
<% #recipe.ingredients.each do |ingredient| %>
<%= ingredient.name %>
<% end %>
and only then all of the ingredients were printed.
What was I doing wrong in the previous tries ?
Thank you.
my ingredient recipe relation defined as follows
class Ingredient < ActiveRecord::Base
has_many :ingredient_recipes
has_many :recipes, :through => :ingredient_recipes
...
class Recipe < ActiveRecord::Base
has_many :ingredient_recipes
has_many :ingredients, :through => :ingredient_recipes
...
accepts_nested_attributes_for :ingredient_recipes ,:reject_if => lambda { |a| a[:content].blank?}
class IngredientRecipe < ActiveRecord::Base
attr_accessible :created_at, :ingredient_id, :order, :recipe_id
belongs_to :recipe
belongs_to :ingredient
end

Answer 1

You don't exactly specify what you are trying to do, so I am presuming you have a page that shows a recipe, with many ingredients that can be edited and added to. In your controller you have something like:
class RecipeController < ApplicationController
def edit
#recipe = Recipe.find(params[:id]
end
end
I am also presuming that you are looking to have a form that post backs to the create action. I therefore think you want a form like this:
<%= form_for #recipe do |form| %>
<%= label_for :name %>
<%= text_field :name %>
<%= form.fields_for :ingredients do |ingredients_fields| %>
<div class="ingredient">
<%= f.text_field :name %>
<%= f.hidden_field :_destroy %>
</div>
<% end %>
<% end %>
Also, change your recipe to accept nested attributes for ingredients, not ingredient_recipes:
class Recipe < ActiveRecord::Base
has_many :ingredient_recipes
has_many :ingredients, :through => :ingredient_recipes
...
accepts_nested_attributes_for :ingredients, :reject_if => lambda { |a| a[:content].blank?}
And finally, add attr_accessible for your content:
class Ingredient < ActiveRecord::Base
attr_accessible :content
...
Does that work for you?