[Ruby on rails] Implementation of like function


Implemented a like function so that other users can like the posting app. Suppose you have a users table, a posts table, and a likes table.


First, consider the relationship between each table and define the association. ** User (1): Likes (many) ** ** Post (1): Like (many) ** I want to make one ** like ** per person per post, so I will also validate it.


class Like < ApplicationRecord
  belongs_to :user
  belongs_to :post

  validates_uniqueness_of :post_id, scope: :user_id


If the post is deleted ** Like ** is also deleted.


has_many :likes, dependent: :destroy


has_many :likes, dependent: :destroy

def already_liked?(post)
  self.likes.exists?(post_id: post.id)

Controller implementation


class LikesController < ApplicationController

  def create
    @like = current_user.likes.create(post_id: params[:post_id])
    redirect_back(fallback_location: root_path)

  def destroy
    @post = Post.find(params[:post_id])
    @like = current_user.likes.find_by(post_id: @post.id)
    redirect_back(fallback_location: root_path)


Routing settings


resources :posts do
  resource :likes, only: [:create, :destroy]

post_likes DELETE /posts/:post_id/likes(.:format) likes#destroy POST /posts/:post_id/likes(.:format) likes#create

view implementation


<% if current_user.already_liked?(post) %>
  <%= link_to post_likes_path(post), method: :delete do %>
    <i class="fas fa-heart"></i>
  <% end %>
<% else %>
  <%= link_to post_likes_path(post), method: :post do %>
    <i class="far fa-heart"></i>
  <% end %>
<% end %>
<%= post.likes.count %>    //Show the number of likes

Do you already like current_user? If it is true, it will be unliked, and if it is false, it will be liked.


There are other ways to implement likes, such as asynchronous implementation. I'm still studying, but I would like to increase what I can study various techniques. Thank you for reading to the end: grin:

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