No routes matches "missing required keys: [:id, :_id]"

Question

How do I solve No routes matches Error message -> No route matches {:action=>"show", :controller=>"cost", :format=>nil, :id=>nil, :travel_id=>nil} missing required keys: [:id, :travel_id]

---

Routes.rb:

 resources :travels do
    resources :costs
  end

  resources :profiles

  resources :homes

  devise_for :users

---

Costs_controller:

  before_action :set_travel
  before_action :set_cost, only: [:show, :edit, :update, :destroy]

    def index
        @travel = Travel.find(params[:travel_id]) 
        if current_user.present?
          @costs = @travel.costs.all
        else
          redirect_to '/users/sign_in'
        end

      end

def new
    @travel = Travel.find(params[:travel_id])
    if current_user.present?
      @cost = @travel.costs.new 
    else
      redirect_to '/users/sign_in'
    end 
  end

def create
    @travel = Travel.find(params[:travel_id])
    @cost = @travel.costs.new(costs_params)
    respond_to do |format|
      if @cost.save
        format.html { redirect_to travel_cost_path(@costs), notice: 'Cost was successfully created.' }
        format.json { render :show, status: :created, location: @cost }
      else
        format.html { render :new }
        format.json { render json: @cost.errors, status: :unprocessable_entity }
      end
    end
  end

---

My model:

class Travel < ActiveRecord::Base
    belongs_to :user
    has_many :costs
end

class Cost < ActiveRecord::Base
    belongs_to :travel  
end

---

My cost _form:

<%= form_for [@travel, @cost] do |f| %>
  <% if @cost.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@cost.errors.count, "error") %> prohibited this cost from being saved:</h2>

      <ul>
      <% @cost.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :value %><br>
    <%= f.text_field :value %>
  </div>
  <div class="field">
    <%= f.label :dat %><br>
    <%= f.date_select :dat %>
  </div>
  <div class="field">
    <%= f.label :cost_type %><br>

    <%= f.select :cost_type, [['Feeds', 'Feeds'],
                         ['Fuel', 'Fuel'],
                         ['Parking', 'Parking'],
                         ['Toll', 'Toll'],
                         ['Accomodation', 'Accomodation'],
                         ['Other', 'Other']]
     %>  
  </div>

  <div class ="field">
    <%= f.label :description %><br>
    <%= f.text_field :description %>
  </div>


  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

Help me if possible, I'm at a time with this problem. Thanks.

Answer 1

Change

format.html { redirect_to travel_cost_path(@costs), notice: 'Cost was successfully created.' }

to

format.html { redirect_to travel_cost_path(@travel, @cost), notice: 'Cost was successfully created.' }