Ruby on Rails: wrong number of arguments (given 0, expected 1)

12,699

You need to pass produit_id as a parameter.

So change this line as so...

<%= link_to 'Ajouter au panier', 
            carts_add_item_path(produit_id: produit.id), method: :post %>

And change your controller method as so...

def add_item
  produit_id = params[:produit_id]
  ...

And change the find_or_create to

@cart_item = CartItem.find_or_create_by(produit_id: produit_id)

This does mean that you can only have one CartItem in your entire application that points to a product... strange design.

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justinedps26
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justinedps26

Updated on June 04, 2022

Comments

  • justinedps26
    justinedps26 7 months

    I have an issue with my add_item method and have trouble to understand why.

    Here is my carts_controller.rb

    class CartsController < ApplicationController
      def index
        @cart_items = CartItem.all
      end
    
      def add_item
        @cart_item = CartItem.new
        produit_id = params[:produit_id]
        @cart_item = CartItem.find_or_create_by(params[:produit][:produit_id])
        @cart_item.save
    
        binding.pry
      end
    end
    

    Here is produits/index.html.erb (where the issue comes from)

    <div id="produits-column-container">
      <% if @produits %>
        <% @produits.in_groups_of(4, false).each do |g| %>
          <% g.each do |produit| %>
          <div id="produits-row-container">
            <div id="fiche-produit-container">
                <div id="produit-img">
                  <%= image_tag produit.photo %>
                </div>
                <div id="produit-nom">
                  <%= produit.nom %>
                </div>
                <div id="produit-prix">
                  <%= number_to_currency(produit.prix, unit: '€', format: "%n%u") %>
                </div>
                <div id="produit-au-panier">
                  <%= image_tag('icon/icon-panier') %>
                  <%= link_to 'Ajouter au panier', carts_add_item_path, method: :post %>
                </div>
             </div>
           </div>
          <% end %>
        <% end %>
      <% end %>
    </div>
    

    The error i'm given is :

    ArgumentError in CartsController#add_item
    wrong number of arguments (given 0, expected 1)
    
    in def add_item(produit_id)
    

    add_item(produit_id) is related to carts_add_item_path

    I also give you the routes :

    Rails.application.routes.draw do
    
      match "/mon-panier" => 'carts#index', via: :get
    
      post 'carts/add_item' => 'carts#add_item'
    
      resources :categories do
        resources :produits
      end
    
      resources :order_abonnements, only: [:create, :update, :delete]
    
      get 'livraisons_type/index'
    
      match "/recapitulatif" => 'recapitulatif#index', via: :get
    
      match "/confirmation-carte-cadeau" => 'recapitulatif#confirmation', via: :get
    
      match "/livraison-carte-cadeau" => 'livraison_carte#index', via: :get
    
      match '/activation-carte' => 'code_carte_cadeau#index', via: :get
    
      match "/offrir-une-box-bretonne" => 'cadeau#index', via: :get
    
      resources :order_items, only: [:create, :update, :destroy]
    
      match "/nos-box" => 'nos_box#index', via: :get
    
      get 'categories/index'
    
      devise_for :admin_users, ActiveAdmin::Devise.config
      ActiveAdmin.routes(self)
    
      match '/informations-penn-ar-box' => 'informations_penn_ar_box#index', via: :get
    
      match '/livraison-box-bretonne' => 'livraison_box_bretonne#index', via: :get
    
      match '/abonnements' => 'abonnements#index', via: :get
    
      devise_for :users, path: '', path_names: { sign_in: 'connexion', sign_out: 'déconnexion'}
    
      resources :users do
        delete 'déconnexion' => 'devise/sessions#destroy'
      end
    
      match '/mon-marche-breton' => 'marche_breton#index', via: :get
    
      root 'home#home'
    end
    

    And the logs :

    Started POST "/carts/add_item" for ::1 at 2017-05-30 09:48:52 +0200
    Processing by CartsController#add_item as HTML
      Parameters: {"authenticity_token"=>"QrToQUHVxjuV5cUvZYHd7tj457htfZohOkmsvNDnKv79P413xjsSfR/8RVXtdIU7/wcmhcxjkU85N13CqJkG2w=="}
      Cart Load (0.3ms)  SELECT  `carts`.* FROM `carts` WHERE `carts`.`id` = 1 LIMIT 1
    Completed 500 Internal Server Error in 27ms (ActiveRecord: 14.9ms)
    
    ArgumentError (wrong number of arguments (given 0, expected 1)):
      app/controllers/carts_controller.rb:6:in `add_item'
    
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      Controller actions are not your ordinary ruby methods and they don't accept parameters like that, in the signature. You're supposed to read params[:produit_id] in the method body.
    • Aleksei Matiushkin
      Aleksei Matiushkin over 5 years
      @SergioTulentsev well, controller actions are ordinary ruby methods after all, they just are called by the engine in some ways that the engine wants to call them.
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      @mudasobwa: you know what I meant. :)
    • justinedps26
      justinedps26 over 5 years
      @SergioTulentsev what do i need to write to fix the issue? i'm in a hurry :)
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      @justinedps26: the answer is in the last sentence of my comment
    • justinedps26
      justinedps26 over 5 years
      @SergioTulentsev i did write your way but nothing changed
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      @justinedps26 you forgot to remove the parameter from the signature?
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      @justinedps26: def add_item(produit_id) should be def add_item
    • zauzaj
      zauzaj over 5 years
      @justinedps26 as @SergioTulentsev explained, controller actions don't receive parameters; as you can see you even don't use such parameter in action body but you access to params. So just remove parameter from method signature and bug will be solved !
    • justinedps26
      justinedps26 over 5 years
      @SergioTulentsev now i have undefined local variable or method cart_items'`
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      @justinedps26: well, that's another issue, which doesn't have anything to do with the original error.
    • justinedps26
      justinedps26 over 5 years
      @SergioTulentsev well, i'll try to figure it out. Thanks for your help
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      Now the question is wrong. The code given can't produce stated error. And, as a general rule, you must not edit questions like that (so that it becomes another question entirely). This invalidates existing answers.
    • justinedps26
      justinedps26 over 5 years
      @SergioTulentsev okay sorry, i just did that to be more clear in the comments
    • Sergio Tulentsev
      Sergio Tulentsev over 5 years
      @justinedps26: no problem. But do keep that in mind.
    • justinedps26
      justinedps26 over 5 years
  • Sergio Tulentsev
    Sergio Tulentsev over 5 years
    That'll be useful, yes, but it's not the cause of the exact problem in the question.
  • justinedps26
    justinedps26 over 5 years
    Thanks, can you let me know the other things that are wrong please?
  • SteveTurczyn
    SteveTurczyn over 5 years
    ? @SergioTulentsev surely it is? He's calling carts_add_item_path which resolves into a call to add_item without arguments. HIs definition of the add_item action expects an argument. Wrong number of arguments, given 0, expected 1.
  • Sergio Tulentsev
    Sergio Tulentsev over 5 years
    No, invocation of carts_add_item_path does not end up with a call to add_item.
  • Sergio Tulentsev
    Sergio Tulentsev over 5 years
    Ah, I see where I could be misunderstood. I was referring to the first part of the answer, the one with carts_add_item_path(produit_id: produit.id). If you do only that (pass parameter this way) and leave the action signature intact, you'll still see the error.
  • Sergio Tulentsev
    Sergio Tulentsev over 5 years
    (took the liberty to format some code. Horizontal scrolling on one-line snippets is horrible)
  • justinedps26
    justinedps26 over 5 years
    @SergioTulentsev the error went away but i now have undefined method []' for nil:NilClass`
  • SteveTurczyn
    SteveTurczyn over 5 years
    That's on line 7? Did you spell "params" correctly?
  • SteveTurczyn
    SteveTurczyn over 5 years
    I just realised you're not even using the argument! Just remove it from the def add_item line.
  • SteveTurczyn
    SteveTurczyn over 5 years
    @SergioTulentsev Yes, my answer was to do both steps, I wasn't giving OP a choice. Good improvement on the formatting, I'll remember that for future.
  • SteveTurczyn
    SteveTurczyn over 5 years
    And which line is the error? Does it say app/controllers/carts_controller.rb:8:in add_item or `app/controllers/carts_controller.rb:9:in add_item' ?
  • justinedps26
    justinedps26 over 5 years
    @SteveTurczyn it says app/controllers/carts_controller.rb:9:in add_item' `
  • justinedps26
    justinedps26 over 5 years