Rails 4 - Nested Form (many to many) - ruby-on-rails

Question

I have the following schema:
attribute
----------
id
name
profile
----------
user_id
attribute_id
value
user
----------
id
name
What I am trying to do is display all the attributes and then for any attribute that the user does have in the profile it fills it in and an update can be performed. My background isn't ruby but I'm testing this framework for a proof of concept before possibly migrating an app.
I have mapped the association like that on the guides on rubyonrails.org (the appointments example)
class Attribute < ActiveRecord::Base
has_many :profiles
has_many :users, through: :profiles
end
class Profile < ActiveRecord::Base
belongs_to :attribute
belongs_to :user
end
class User < ActiveRecord::Base
has_many :profiles
has_many :attributes, through: :profiles
accepts_nested_attributes_for :profiles
end
I took the approach of using nested forms but unable to pass the model through even though the accepts_nested_attributes_for has been set.
<%= form_for(#user) do |f| %>
<% Attribute.all.each do |attribute| %>
<div>
<%= attribute.name %>
</div>
<div>
<%= f.fields_for :profiles do |upp| %>
<%= upp.hidden_field :user_id, :value => #user.id %>
<%= upp.hidden_field :attribute_id, :value => #attribute.id %>
<%= upp.text_field :value %>
<% end %>
</div>
<% end %>
<div>
<%= f.submit %>
</div>
<% end %>
e.g
Attributes
A
B
C
User has attribute A
A ["hello world"]
B [ ]
C [ ]
Attributes are dynamic, so if 2 new attributes are added, D and E would be shown as well
A ["hello world"]
B [ ]
C [ ]
D [ ]
E [ ]
How can I setup this form correctly so that it can be passed through as a model for saving? I assume the json would be something like
profile_attributes { [user_id:1 attribute_id:1 value:'hello world'], [user_id:1 attribute_id:2 value:''] }
I know the above form setup is not quite right but that is just one of several attempts I tried to see what it renders.
I tried:
<%= f.fields_for #user.profiles do |pp| %>
<% end %>
I even tried manually setting the field as arrays (similiar to asp.net mvc):
id=user[profiles][user_id]
id=user[profiles][attribute_id]
Controllers (they're empty shells at the moment, I just wanted to see the json output in the console)
class UsersController < ApplicationController
before_action :set_user, only: [:show, :edit, :update, :destroy]
private
# Use callbacks to share common setup or constraints between actions.
def set_user
#user = User.find(params[:id])
end
end
class ProfileController < ApplicationController
def edit
#user = User.find(params[:id])
end
def update
respond_to do |format|
#user = User.find(params[:id])
end
private
def user_params
params.require(:user).permit(profiles_attributes: [:user_id, :attribute_id, :value])
end
end
end
I've tried many different approaches but with no success. Sometimes the form shows duplicated fields with same values, sometimes the form is shown but value is blank and upon submission complains about unpermitted parameter yet it was set in the controller.
Of course all the above can be done using javascript but I wanted to see if it was possible just using the model approach and nesting it.

Answer 1

You can do like this :
move form to your users/edit.html.erb and modify your users_controller as below
class UsersController < ApplicationController
before_action :set_user, only: [:show, :edit, :update, :destroy]
def edit
#user.profiles.build
end
def update
if #user.update(user_params)
#redirect user where you want
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_user
#user = User.find(params[:id])
end
def user_params
#permit user attributes along with profile attributes
end
end