Saving array of nested attributes with accepts_nested_attributes_for

Question

Project and tasks have a one-to-many relationship, and project accepts_nested_attributes_for :tasks.

In the form, my task objects look like:

project[tasks][2][assigned_time]
project[tasks][2][due_time]

When the form is submitted I get a hash like:

Parameters: {"utf8"=>"✓", "authenticity_token"=>"...=", "project"=>{"id"=>"1", "tasks"=>{"1"=>{"assigned_time"=>"09:00", "due_time"=>"17:00"}, "2"=>{"assigned_time"=>"09:00", "due_time"=>"17:00"}}

Then I expect them to be saved by just saving the project object:

project = Project.find(params[:id])

respond_to do |format|
  if project.update_attributes(params[:tasks])

But I get:

WARNING: Can't mass-assign protected attributes: id SQL (0.3ms) ROLLBACK Completed in 169ms

ActiveRecord::AssociationTypeMismatch (Task(#2188181260) expected, got Array(#2151973780)):

Any ideas how to fix this?

kjprice · Accepted Answer · 2015-03-16 19:15:15Z

4

In your Projects model, accepts_nested_attributes_for :tasks. This will define @project.tasks_attributes= if you have a has_many :tasks association or @project.task_attributes= if you have a has_one :task association.

In your form, the following:

= form_for @project do |f|
  = f.label :project_attribute
  = f.text_field :project_attribute

  = f.fields_for :tasks do |t|
    = t.label :task_attribute
    = t.text_field :task_attribute

In your projects controller, the following:

def new
  @project = Project.new
  @project.tasks.build #=> if has_many
  @project.build_task  #=> if has_one
end

edited Mar 16, 2015 at 19:15

kjprice

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answered Jun 20, 2011 at 18:01

awilkening

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Comments

crsde · Accepted Answer · 2011-05-01 17:47:37Z

1

I think, you just forget to add task_attributes to attr_accessible list in your Project model:

attr_accessible :tasks_attributes, ...

And also, note, that, maybe you generating wrong form, because in my current application, form with nested attributes uses task_attributes method, not tasks (like in your hash)

edited May 1, 2011 at 17:47

answered May 1, 2011 at 17:19

crsde

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3 Comments

99miles Over a year ago

Actually I had to define task_attributes=. I don't fully understand it, but it's working. I'm curious for the explanation if anyone knows

crsde Over a year ago

Add your Project model to question, please

Winston Kotzan Over a year ago

attr_accessible was deprecated in Rails 4 in favor of Strong Parameters

Marian · Accepted Answer · 2024-08-01 10:29:59Z

0

Use form_with instead form_for in view helped me:

<%= form_with model: @book do |f| %>
  <%= f.label :name %>
  <%= f.text_field :name %>

  <%= f.fields_for :items do |ff| %>
    <%= ff.label :item_name %>
    <%= ff.text_field :item_name %>
  <% end %>
<% end %>

My controller:

def new
  @book = Book.new
  @book.items.build
end

def create
  current_user.books << Book.new(book_params)
end

private

def book_params
  params.require(:book).permit!
end

answered Aug 1, 2024 at 10:29

Marian

11 bronze badge

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