Has many :through association: Can't mass-assign protected attributes: model_id? - ruby-on-rails

Question

I'm trying to create my Dog and add categories to it but I get the error:
WARNING: Can't mass-assign protected attributes: category_id
SQL (49.0ms) INSERT INTO "categorizations" ("dog_id", "category_id", "created_at", "cat_id", "mouse_id", "updated_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id" [["dog_id", 7], ["category_id", 1], ["created_at", Sun, 29 Jul 2012 20:34:27 JST +09:00], ["cat_id", nil], ["mouse_id", nil], ["updated_at", Sun, 29 Jul 2012 20:34:27 JST +09:00]]
(105.0ms) COMMIT
Completed 500 Internal Server Error in 669ms
ArgumentError (too few arguments):
app/controllers/dogs_controller.rb:7:in `format'
app/controllers/dogs_controller.rb:7:in `create'
Don't know why this is true since I have in my model:
class Dog < ActiveRecord::Base
attr_accessible :name, :category_ids
belongs_to :user
has_many :categorizations
has_many :categories, :through => :categorizations
accepts_nested_attributes_for :categories
validates :name, :presence => true
validates :user_id, :presence => true
end
As you can see the join table is Categorizations:
class Categorization < ActiveRecord::Base
belongs_to :dog
belongs_to :category
belongs_to :cat
belongs_to :mouse
end
And I select the categories desired on the form. Here's the model:
class Category < ActiveRecord::Base
attr_accessible :name
belongs_to :user
has_many :categorizations
has_many :dogs, :through => :categorizations
has_many :cats, :through => :categorizations
has_many :mouses, :through => :categorizations
validates :name, :presence => true, :uniqueness => true
before_validation :downcase_name
private
def downcase_name
self.name = self.name.downcase if self.name.present?
end
end
For some strange reason it still assigns the categories when looking in the database but this may be causing other issues i'm having. What could be the problem?
UPDATE
Here is my Dog form:
<%= form_for(#dog, :remote => true) do |f| %>
<%= f.label :name, "Name" %>
<%= f.text_field :name %>
<%= f.label :category, "Categories" %>
<%= f.select :category_ids, Category.all.collect {|c| [c.name, c.id]}, {}, { :multiple => true, } %>
<% end %>
Still get the Mass-assignment error when I try:
attr_accessible :name, :category_ids
WARNING: Can't mass-assign protected attributes: category_id
attr_accessible :name, :category_id, :category_ids
# It says this for each category I want to put on the Dog.
WARNING: Can't mass-assign protected attributes: category_id
attr_accessible :name, :category_id
WARNING: Can't mass-assign protected attributes: category_ids
UPDATE 2
I was able to get rid of the ArgumentError though by adding the respond_to for the controller action:
def create
#dog = current_user.dogs.new(params[:dog])
respond_to do |format|
if #dog.save
format.js
else
format.js
end
end
end
If add 2 or more categories to the Dog ( in this case 3) . It adds them in the database and does mass assign them but server keeps saying this in the log:
Started POST "/dogs" for 127.0.0.1 at 2012-07-29 20:44:15 -0400
Processing by DogsController#create as JS
Parameters: {"utf8"=>"Γ£ô", "authenticity_token"=>"wuPqA6e8MqF/yW3VQ+sfLiyf0olOWgEpnVC2qawQE0I=", "dog"
Add Dog"}
User Load (2.0ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 LIMIT 1
Category Load (0.0ms) SELECT "categories".* FROM "categories" WHERE "categories"."id" IN (1, 2, 3)
(1.0ms) BEGIN
(0.0ms) COMMIT
(0.0ms) BEGIN
(1.0ms) SELECT 1 FROM "categories" WHERE ("categories"."name" = 'furry' AND "categories"."id" != 1) LI
(1.0ms) SELECT 1 FROM "categories" WHERE ("categories"."name" = 'house trained' AND "categories"."id" != 2) LIMIT
(0.0ms) SELECT 1 FROM "categories" WHERE ("categories"."name" = 'wild' AND "categories"."id" != 3) LIMIT
SQL (1.0ms) INSERT INTO "dogs" ("created_at", "name", "updated_at", "user_id") VALUES ($1, $2, $3, $4
"name", "Omni Dog"], ["updated_at", Mon, 30 Jul 2012 09:44:15 JST +09:00], ["user_id", 1]]
WARNING: Can't mass-assign protected attributes: category_id
[1m[35mSQL (1.0ms)[0m INSERT INTO "categorizations" ("dog_id", "category_id", "created_at", "cat_id", "mouse_id", "updated_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id" [["dog_id", 31], ["category_id", 1], ["created_at", Mon, 30 Jul 2012 09:44:15 JST +09:00], ["cat__id", nil], ["mouse_id", nil], ["updated_at", Mon, 30 Jul 2012 09:44:15 JST +09:00]]
WARNING: Can't mass-assign protected attributes: category_id
[1m[36mSQL (1.0ms)[0m [1mINSERT INTO "categorizations" ("dog_id", "category_id", "created_at", "cat__id", "mouse_id", "updated_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id"[0m [["dog_id", 31], ["category_id", 2], ["created_at", Mon, 30 Jul 2012 09:44:16 JST +09:00], ["cat__id", nil], ["mouse_id", nil], ["updated_at", Mon, 30 Jul 2012 09:44:16 JST +09:00]]
WARNING: Can't mass-assign protected attributes: category_id
[1m[35mSQL (1.0ms)[0m INSERT INTO "categorizations" ("dog_id", "category_id", "created_at", "cat__id", "mouse_id", "updated_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id" [["dog_id", 31], ["category_id", 3], ["created_at", Mon, 30 Jul 2012 09:44:16 JST +09:00], ["cat__id", nil], ["mouse_id", nil], ["updated_at", Mon, 30 Jul 2012 09:44:16 JST +09:00]]
Rendered dogs/_dog.html.erb (1.0ms)
Rendered dogs/create.js.erb (3.0ms)
Completed 200 OK in 203ms (Views: 25.0ms | ActiveRecord: 52.0ms)
Is this a problem if it's technically working?

Answer 1

You have an extra s here:
class Dog < ActiveRecord::Base
attr_accessible :name, :category_ids
...
category_id is a column on the dogs table, So, just remove it:
class Dog < ActiveRecord::Base
attr_accessible :name, :category_id

Answer 2

I needed to change this:
#dog = current_user.dogs.new(params[:dog])
To this instad:
#dog = current_user.dogs.build(params[:dog])
And then it started to work for me.