Model won't update on submission - ruby-on-rails

Question

Im getting this weird error when i want to update my model (model name carts).
Error : The action 'update' could not be found for CartsController
this is my carts_controller.rb :
class CartsController < ApplicationController
include CartForcable
before_action :scoped_cart, only: [:show, :update]
def show
end
private
def scoped_cart
force_cart! lambda {|r| r.includes(:entries => {:sign => [:dimensions, :substrates]})}
end
def update
#cart = #cart.find(params[:id])
if #cart.update_attributes(cart_params)
flash[:notice] = translate 'flash.notice'
else
flash[:error] = translate 'flash.error'
end
support_ajax_flashes!
respond_to do |format|
format.html # renders view
format.json { render json: #entry }
end
end
end
and these are my routes.rb :
resources :categories, only: [:index] do
resources :signs, shallow: true, only: [:index]
end
resources :carts, only: [:show, :update]#, param: :cart_permalink
resource :cart, as: :user_cart, only: [:show, :update], param: :cart_permalink do
resources :cart_entries, only: [:index, :create, :update, :destroy], as: 'entries', path: 'entries'
end
resource :user, only: [:edit, :show, :update], as: 'current_user', path: 'profile'
resources :signs, only: [:show]
resources :pages, only: [:show], param: :permalink
and my show.html.erb has this form :
<%= form_for #cart, :url => {:controller => "carts", :action => "update" } do |f| %>
<%= f.label :name %>
<%= f.text_field :name %>
<%= f.label :email %>
<%= f.text_field :email %>
<%= f.label :regnum %>
<%= f.text_field :regnum %></br>
<%= button_to "Order/update", {:controller => "carts",:action =>
'update', :id => #cart.id }, :method => :update %>
<% end %>
After i enter name or number (for example), and click update button or something, it doesnt upload any data into model carts(which has the right columns).
Thanks,
Michael

Answer 1

Your update method is private; controller actions need to be public. Move
def update
#cart = Cart.find(params[:id])
...
end
to be above the
private
line. You need to do the find on the Cart model, not a #cart instance.
You can use a show action although edit would be more standard and fits right in with the RESTful routes without the need to override convention. The Rails routing guide should help here: http://guides.rubyonrails.org/routing.html
Additionally, you need to define the value of #cart in your edit action:
def edit
#cart = Cart.find(params[:id])
end
This will ensure it has a value on the edit form and so comes back into your update action through the parameters.
So if you try to edit a cart with something like /carts/12345/edit (where 12345 is the id of the cart you want to update) it should all hang together.

Answer 2

This looks wrong:
#cart = #cart.find...
don't you mean...?:
#cart = Cart.find...
And it seems you are using "cart_permalink" instead of "id" on your routes
resource :cart, as: :user_cart, only: [:show, :update], param: :cart_permalink do
Check the server log and see the name of the parameter that holds the ID, also run "bundle exec rake routes" to double check.