using an array with fields_for

Question

How can I iterate through an array of objects (all the same model) using fields_for ? The array contains objects created by the current_user.

I currently have:

<%= f.fields_for :descriptionsbyuser do |description_form| %>
<p class="fields">
    <%= description_form.text_area :entry, :rows => 3 %>
    <%= description_form.link_to_remove "Remove this description" %>
    <%= description_form.hidden_field :user_id, :value => current_user.id %>
</p>
<% end %>

But I want to replace the :descriptionsbyuser with an array I created in my controller - @descriptionsFromCurrentUser

This is also inside Ryan Bate's "nested_form_for"

Any pointers would be greatly appreciated!

Adam

Answer 1

To use a collection for fields_for and have it work the way that you expect, the model needs accept nested attributes for the collection. If the collection is an ActiveRecord one-to-many relationship, use the accepts_nested_attributes_for class macro. If the collection is not an ActiveRecord one-to-many relationship, you'll need to implement a collection getter and a collection attributes setter.

If it is an ActiveRecord relationship:

class Person
  has_many :projects

  # this creates the projects_attributes= method
  accepts_nested_attributes_for :projects
end

If it is a non-ActiveRecord relationship:

class Person
  def projects
    ...
  end

  def projects_attributes=(attributes)
    ...
  end
end

Either way, the form is the same:

<%= form_for @person do |f| %>
  ...
  <%= f.fields_for :projects, @active_projects do |f| %>
    Name: <%= f.text_field :name %>
  <% end %>
  ...
<% end %>

Answer 2

Docs for fields_for clearly shows you the way of using arrays:

Or a collection to be used:

<%= form_for @person do |person_form| %>
  ...
  <%= person_form.fields_for :projects, @active_projects do |project_fields| %>
    Name: <%= project_fields.text_field :name %>
  <% end %>
  ...
<% end %>

@active_projects here is your array.

Answer 3

i found this to be the cleanest way

if you are working with straight data and want to send back an array without using any of these @objects

<%= form_for :team do |t| %>
  <%= t.fields_for 'people[]', [] do |p| %>
    First Name: <%= p.text_field :first_name %>
    Last Name: <%= p.text_field :last_name %>
  <% end %>
<% end %>

your params data should return like this

"team" => {
  "people" => [
    {"first_name" => "Michael", "last_name" => "Jordan"},
    {"first_name" => "Steve", "last_name" => "Jobs"},
    {"first_name" => "Barack", "last_name" => "Obama"}
  ]
}

Answer 4

An addition to barelyknown's answer (wasn't able to add as a comment due to reputation points) -

For the non-activerecord case, I also had to define persisted? in my class in addition to *_attributes=(attributes).