Btukfyl

I'm trying to change my model association from a has_many (which works) to a has_one but I'm running into issues.

when i go to:

localhost:3000/users/1/security_badge/new

i get this in the logs

NoMethodError (undefined method `new' for nil:NilClass):

User model:

class User < ApplicationRecord

  has_one :security_badge, dependent: :destroy

end

SecurityBadge model:

class SecurityBadge < ApplicationRecord    

  belongs_to :user    

end

my routes:

  resources :users do

    resource :security_badge

  end

some of my controller security_badges_controller:

  before_action :set_user, only: [:index, :show, :new, :edit, :create, :update]

  before_action :set_security_badge, only: [:show, :edit, :update, :destroy]



  def new

    @security_badge = @user.security_badge.new

  end



  def edit

  end



  def create

    @security_badge = @user.security_badge.new(security_badge_params)



    respond_to do |format|

      if @security_badge.save

        format.html { redirect_to user_security_badge_path(@security_badge.user), notice: 'Security badge was successfully created.' }

      else

        format.html { render :new }

      end

    end

  end



  private

    # Use callbacks to share common setup or constraints between actions.

    def set_user

      @user = User.find(params[:user_id])

    end



    def set_security_badge

      @security_badge = SecurityBadge.find(params[:id])

    end

Update

this is in my _form:

<%= form_with(model: [@user, security_badge], local: true) do |form| %>

  <% if security_badge.errors.any? %>

    <div id="error_explanation">

      <h2><%= pluralize(security_badge.errors.count, "error") %> prohibited this security_badge from being saved:</h2>



      <ul>

      <% security_badge.errors.full_messages.each do |message| %>

        <li><%= message %></li>

      <% end %>

      </ul>

    </div>

  <% end %>



  <div class="field">

    <%= form.label :name %>

    <%= form.text_field :name, autofocus:true, class: "form-control" %>

  </div>



  <br>

  <div class="row float-right">

    <div class="col-md-12 actions">

        <%= link_to "Cancel", user_path(@security_badge.user), id: 'cancel', class: 'btn btn-outline-secondary' %>

        <%= form.submit "Submit", id: "submit", class: 'btn btn-success' %>

    </div>

  </div>



<% end %>

new view template:

<%= render 'form', security_badge: @security_badge %>

Use @user.build_security_badge (method provided by the has_one association macro) instead of @user.security_badge.new (security_badge is nil, that's why you get an error).

https://guides.rubyonrails.org/association_basics.html#has-one-association-reference