Link_to create with parameter before - ForbiddenAttributesError now - ruby-on-rails

Question

What I Want:
I need in a view a button or a link (it doesn't matter) to the create action of Reservation controller and to give it a parameter too.
And resolve the ForbiddenAttributesError that now gives me.
Here are my model and controller:
Reservation model
class Reservation < ActiveRecord::Base
belongs_to :user
belongs_to :dinner
end
Reservation controller
class ReservationsController < ApplicationController
load_and_authorize_resource
def show
#reservations = Reservation.joins(:user).where('dinner_id' => params[:dinner_id]).select("users.*,reservations.*")
#dinnerid = params[:dinner_id]
respond_to do |format|
format.html
format.json { render :json => #reservations }
end
end
def create
#reservation = Reservation.new(params[:reservation])
#reservation.user_id = current_user.id
respond_to do |format|
if #reservation.save
format.html { redirect_to #reservation, notice: 'Reservation was successfully created.' }
format.json { render :show, status: :created, location: #reservation }
else
format.html { render :show }
format.json { render json: #reservation.errors, status: :unprocessable_entity }
end
end
end
# Never trust parameters from the scary internet, only allow the white list through.
def reservation_params
params.require(:reservation).permit(:dinner_id)
end
end
EDIT: After the suggestion of #Rahul Singh this is my actual code with relative error:
<p id="notice"><%= notice %></p>
<table>
<thead>
<tr>
<th>Id</th>
<th>User id</th>
<th>Dinner id</th>
<th>User email</th>
<th>User name</th>
</tr>
</thead>
<tbody>
<% #reservations.each do |reservation| %>
<tr>
<td><%= reservation.id %></td>
<td><%= reservation.user_id %></td>
<td><%= reservation.dinner_id %></td>
<td><%= reservation.user.email %></td>
<td><%= reservation.user.name %></td>
</tr>
<% end %>
</tbody>
</table>
<br/>TRY 00a <br/>
<%= form_for(Reservation.new) do |f| %>
<%= f.hidden_field( :dinner_id, :value => #dinnerid.to_s) %>
<%= f.submit "Join1" %>
<% end %>
<br/> !!!!!!!!!!ERROR : ActiveModel::ForbiddenAttributesError
<br/>TRY 00b <br/>
<%= link_to "Join1", reservations_path(dinner_id:#dinnerid.to_s), method: :post %>
<br/> !!!!!!!!!!ERROR : param is missing or the value is empty: reservation
I provide a sreenshot for the error :
Error of the form : https://www.dropbox.com/s/i2x1m520ptqdj56/createReservationForm.jpg
Error of the link_to : https://www.dropbox.com/s/8xjwee5oo7q6uhk/createReservationLink_to.jpg

Answer 1

This should work
<%= form_for(Reservation.new) do |f| %>
<%= f.hidden_field( :dinner_id, :value => #dinnerid.to_s) %>
<%= f.submit "Join1" %>
<% end %>
clicking on Join1 button will submit form to ReservationsController create action.
and with link try this
<%= link_to "Join1", reservations_path(dinner_id:#dinnerid.to_s), method: :post %>
for above to work,add following in your routes.rb
resources :reservations

Answer 2

Change this line -> #reservation = Reservation.new(params[:reservation])
To this -> #reservation = Reservation.new reservation_params
and try again ;).

Answer 3

I'm wondering if it wouldn't be better to have your reservation routes as a nested resource of dinners.
It seems reservations can't exist without a dinner, so I'd make that explicit like this:
# config/routes.rb
resources :dinners do
resources :reservations
end
Run rake routes to see how this would change the routes.
You'd now have the dinner id passed along:
# app/views/dinners/show.html.erb
<%= button_to 'Reserve this dinner', dinner_reservations_path(#dinner) %>
The button would route to the create action because a button's default HTTP method is POST.
# app/controllers/reservations_controller.rb
class ReservationsController < ApplicationController
before_action :set_dinner
def create
#dinner.reservations.create! user: current_user
# would render reservations/create.html.erb
end
private
def set_dinner
#dinner = Dinner.find(params[:id])
end
end
This doesn't fix your immediate problem of just getting that link to work. But I think you'd be a lot better served structuring your app more like the above going forward.
Full disclosure: the person who asked this question contacted me on twitter personally, so I took some liberties in answering this question with a more general design suggestion.

Answer 4

I'm not sure this is the "best" approach but I think its the easiest one.
You could do something with string interpolation:
a href="/reservations?dinner=#{dinner.id}" Join
then you could get the paramter with
params[:dinner]