Param is missing or the value is empty: vote - ruby-on-rails

Question

I have this newbie error when i want to upvote a "hack" :
ActionController::ParameterMissing at /hacks/6/upvote
param is missing or the value is empty: vote
With Request parameters exemple :
{"_method"=>"post", "authenticity_token"=>"r+fYieTQDsD6fuonr3oe0YEzkzBXH1S8k6bDENS0wCVr3LEpxGA4mps5saM4RQLvBNDVzsm2zXpGm9TKe3ZIYA==",
"controller"=>"hacks", "action"=>"upvote", "id"=>"6"}
I don't understand why my #vote do not appear in parameters...
Controller hacks_controller.rb
class HacksController < ApplicationController
skip_before_action :authenticate_user!, only: [:upvote]
def upvote
#vote = Vote.new(vote_params)
#hack = Hack.find(params[:id])
# raise
#vote.hack = #hack
if #vote.save
redirect_to root_path
else
p 'Problème de #vote.save !'
end
end
private
def vote_params
params.require(:vote).permit(:hack_id, :user_id)
end
end
Model Vote.rb
class Vote < ApplicationRecord
belongs_to :user
belongs_to :hack
validates :hack, presence: true
end
Thanks !

Answer 1

The Rails strong parameters are meant as mass assignment protection and are not suited to this case.
To create an additional CRUD method properly you can just add the additional route to resources:
resources :hacks do
post :upvote
delete :downvote
end
Note that we are using POST not GET as this is a non-idempotent operation.
You also don't need to pass any parameters. :hacks_id will be present in the path and you should fetch the current user id from the session and not the request parameters.
Passing a user id via the parameters is a really bad practice as its very trivial to spoof by using just the web inspector.
class HacksController < ApplicationController
before_action :set_hack!, except: [:new, :index, :create]
# POST /hacks/:hack_id/upvote
def upvote
#vote = #hack.votes.new(user: current_user)
if #vote.save
redirect_to #hack, success: 'Vote created'
else
redirect_to #hack, error: 'Vote could not be created'
end
end
# DELETE /hacks/:hack_id/downvote
def downvote
#vote = #hack.votes.where(user: current_user).first!
#vote.destroy
redirect_to #vote, success: 'Vote deleted'
end
private
# this will raise ActiveRecord::RecordNotFound if
# the id or hack_id param is not valid. This triggers a 404 response
def set_hack!
if params[:id].present?
Hack.find(params[:id])
else
Hack.find(params[:hack_id])
end
end
end
Then in your view you can create the links / buttons like so:
<% if current_user && #hack.votes.where(user: current_user) %>
<%= button_to 'Downvote', hack_downvote_path(#hack), method: :delete %>
<% else %>
<%= button_to 'Upvote', hack_upvote_path(#hack), method: :post %>
<% end %>