[RUBY] Rails follow function

① Model (3 steps)

○ Create the required models (2)

  1. USER (created with devise)  2. Relationships   rails g model Relationship follower_id:integer followed_id:integer

    create_table "relationships", force: :cascade do |t| t.integer "follower_id" t.integer "followed_id" t.datetime "created_at", null: false t.datetime "updated_at", null: false end

○ Association

Added to each model.

Relationship model [Relationships.rb]

belongs_to :follower, class_name: "User"
belongs_to :followed, class_name: "User"

User model [User.rb]

#Following has_many :follower, class_name: "Relationship", foreign_key: "follower_id", dependent: :destroy


    has_many :followed, class_name: "Relationship", foreign_key: "followed_id", dependent: :destroy

#People who follow has_many :follower_user, through: :followed, source: :follower #People being followed has_many :following_user, through: :follower, source: :followed

: point_up: Relationship model can also be divided into "follower" and "followed" By adding: point_up: foreign_key, each can be obtained through the Relationship model.

: point_up: Through each source model

○ Method definition (3) [User.rb]

1. follow method = follow

  def follow(user_id)
   follower.create(followed_id: user_id)

2. unfollow method = unfollow

  def unfollow(user_id)
   follower.find_by(followed_id: user_id).destroy

3. following method = Confirm if you are already following

  def following?(user)

It is used when conditional branching of display with: point_up: html. If user is included in the argument, return true = If true, "Unfollow" is displayed.


○ Method definition: Relationships Controller

def create # follow method defined in the User model to follow current_user.follow(params[:user_id]) redirect_to request.referer # Get the URL before the transition and redirect end

def destroy # unfollow unfollow method defined in User model current_user.unfollow(params[:user_id]) redirect_back(fallback_location: root_path) end

def follower #follower list user = User.find(params[:user_id]) @users = user.following_user

.follower_user method: Defined in User model


def followed #followed list user = User.find(params[:user_id]) @users = user.follower_user

.follower_user method: Defined in User model



Added for list of create (follow), destroy (unfollow) and follows, followers

resources :users
 resource :relationships, only:[:create, :destroy]

 get 'follows' => 'relationships#follower'
 get 'followers' => 'relationships#followed'


・ Follow button (follow / unfollow)

Add a link to the part where you want to display the follow button

 <% if current_user != user %>
  <% if current_user.following?(user) %>

<% = link_to'Unfollow', user_relationships_path (user.id), method:: delete, class: "btn btn-default"%> <% else %> <% = link_to'Follow', user_relationships_path (user.id), method :: POST, class: "btn btn-primary"%> <% end %> <% end %>

・ Follower.follows list

Create follower.html.erb and follows.html.erb files in relationships Described in each file as follows

If there is a User in the conditional branch of <% if @ users.count> 0%>, display it in each statement and display it. If not, ** No user ** is displayed

 <% if @users.count > 0 %>
   <table class="table">
       <% @users.each do |user| %>
           <td><%= @user.name %></td>
Number of followers: <% = @ user.follower.count%> Number of followers: <% = @ user.followed.count%>  <% if current_user != @user %>  <% if current_user.following?(@user) %> <% = link_to'Unfollow', user_relationships_path (@ user.id), method:: delete, class: "btn btn-default"%> <% else %> <% = link_to'Follow', user_relationships_path (@ user.id), method :: POST, class: "btn btn-primary"%> <% end %> <% end %> <%= link_to "Show", @user %> <% end %> <% else %>

No users <% end %>

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