Ruby on Rails：删除用户的投票记录

Question

I created a basic ruby on rails apps where users can vote for a pin. They can vote for a pin using an ajax method.

What I want now is to let users delete their vote.

Here is my implementation:

pins_controller.rb:

  def upvote
    @pin = Pin.friendly.find(params[:id])
    @pin.votes.create(user_id: current_user.id)
    respond_to do |format|
    format.html { redirect_to @pin }
    format.js
    end
  end

users_controller.rb

  def upvote
    @pin = Pin.friendly.find(params[:id])
    @pin.votes.create(user_id: current_user.id)
    respond_to do |format|
    format.html { redirect_to @pin }
    format.js
    end
  end

vote.rb

class Vote < ActiveRecord::Base
    belongs_to :user
    belongs_to :pin, counter_cache: true
    validates_uniqueness_of :pin_id, scope: :user_id
end

pin.rb

has_many :votes, dependent: :destroy

in my views, they can upvote a pin through this:

<% if @pin.votes.where(user_id: current_user.id).empty? %>
  <%= link_to upvote_pin_path(@pin), method: :put, remote: true do %>
    Vote for this pin
  <% end %>
<% else %>
<% end %>

Now I would like to let users delete a vote record, but I am not sure how I can set this up, I tried to create a downvote method in my controllers, but nothing worked.

Any ideas to put me on track ?

Answer 1

More information would be helpful. For example, I am assuming there are some sorts of restrictions, such as every vote has to be tied to a user and only one vote per pin per user. However, the solutions is something like

In your pins_controller.rb

def downvote
   @pin = Pin.friendly.find(params[:id])
   Vote.where(:user_id => current_user.id, :pin_id => @pin.id).each { |v| v.delete }

   respond_to do |format|
     format.html { redirect_to @pin }
     format.js
   end
end

And in your views

 <% if @pin.votes.where(user_id: current_user.id) %>
   <%= link_to downvote_pin_path(@pin), method: :put, remote: true do %>
     DELETE your Vote for this Pin!
   <% end %>
 <% else %>
 <% end %>

You probably want to create a convenience method for that check

In models/pin.rb

 class Pin
      ...
      def owned?(id)
        self.votes.where(user_id: id).count > 0 ? true : false
      end
 end