ndefined method `name' for nil:NilClassのエラーが出力される。

Question

ndefined method `name' for nil:NilClassのエラーが出て困っています。
![]

下記HTMLで<li class="nav-item"><a href="<%= followings_user_path(@user) %>" class="nav-link" >Followings</a></li>を実行した際にエラーが出ます。

<div class="row">
  <div class="col-sm-12">
    <ul class="nav nav-tabs nav-justified mb-3">
      <li class="nav-item"><a href="<%= books_path%>" class="nav-link">books</a></li>
      <li class="nav-item"><a href="<%= followings_user_path(@user) %>" class="nav-link" >Followings</a></li>
      <li class="nav-item"><a href="<%= followers_user_path(@user) %>" class="nav-link">Followers</a></li>
      <li class="nav-item"><a href="#" class="nav-link">likes</a></li>
      <li class="nav-item"><a href="#" class="nav-link">mypages</a></li>
    </ul>
  </div>
</div>

下記HTMLでエラーが出ます。

<div class="row">
  <aside class="col-sm-4">
    <div class="card">
      <div class="card-header">
        <h3 class="card-title"><%= @user.name %></h3>
      </div>
      <div class="card-body">
        <img class="rounded img-fluid" src="<%= gravatar_url(@user, { size: 500 }) %>" alt="">
      </div>
    </div>
    <%= render 'relationships/follow_button', user: @user %>
  </aside>
  <div class="col-sm-8">
    <ul class="nav nav-tabs nav-justified mb-3">
      <li class="nav-item"><a href="<%= user_path(@user) %>" class="nav-link <%= 'active' if current_page?(user_path(@user)) %>">Microposts  <span class="badge badge-secondary"><%= @count_microposts %></span></a></li>
      <li class="nav-item"><a href="<%= followings_user_path(@user) %>" class="nav-link <%= 'active' if current_page?(followings_user_path(@user)) %>">Followings  <span class="badge badge-secondary"><%= @count_followings %></span></a></li>
      <li class="nav-item"><a href="<%= followers_user_path(@user) %>" class="nav-link <%= 'active' if current_page?(followers_user_path(@user)) %>">Followers  <span class="badge badge-secondary"><%= @count_followers %></span></a></li>
    </ul>
    <%= render 'users', users: @followings %>
  </div>
</div>

コントローラー側は下記です。def following内で@user = User.find(params[:id])を行なっているのですが、上手くview側に受けわたせていないようです。

class UsersController < ApplicationController
 before_action :require_user_logged_in, only: [:index, :show, :followings, :followers]
  def index
    @users = User.order(id: :desc).page(params[:page]).per(25)
  end

  def show
    @user = User.find(params[:id])
  end

  def new
    @user = User.new
  end

  def create
    @user = User.new(user_params)

    if @user.save
      flash[:success] = 'ユーザを登録しました。'
      redirect_to @user
    else
      flash.now[:danger] = 'ユーザの登録に失敗しました。'
      render :new
    end
  end
end

def followings
    @user = User.find(params[:id])
    @followings = @user.followings.page(params[:page])
    counts(@user)
end
  
def followers
    @user = User.find(params[:id])
    @followers = @user.followers.page(params[:page])
    counts(@user)
end


private

  def user_params
    params.require(:user).permit(:name, :email, :password, :password_confirmation)
  end

```routes.rb

Rails.application.routes.draw do
root to: 'toppages#index'

get 'login', to: 'sessions#new'
post 'login', to: 'sessions#create'
delete 'logout', to: 'sessions#destroy'
get 'signup', to: 'users#new'
resources :users, only: [:index, :show, :new, :create]do
member do
get :followings
get :followers
get :likes
end
end

resources :microposts, only: [:create, :destroy]
resources :relationships, only: [:create, :destroy]
resources :favorites, only: [:create, :destory]
delete 'favorites', to: 'favorites#destroy'
end

```user.rb
class User < ApplicationRecord
    before_save { self.email.downcase! }
    validates :name, presence: true, length: { maximum: 50 }
    validates :email, presence: true, length: { maximum: 255 },
                    format: { with: /\A[\w+\-.]+@[a-z\d\-.]+.[a-z]+\z/i },
                    uniqueness: { case_sensitive: false }
    has_secure_password
    has_many :microposts
    has_many :relationships
    has_many :followings, through: :relationships, source: :follow
    has_many :reverses_of_relationship, class_name: 'Relationship', foreign_key: 'follow_id'
    has_many :followers, through: :reverses_of_relationship, source: :user
    has_many :favorites
    has_many :darling, through: :favorites, source: :micropost
    has_many :reverses_of_ravorite, class_name: 'Favorite', foreign_key: 'micropost_id'
    has_many :favorited, through: :reverses_of_favorite, source: :user

    
    def follow(other_user)
        unless self == other_user
            self.relationships.find_or_create_by(follow_id: other_user.id)
        end
    end

    def unfollow(other_user)
        relationship = self.relationships.find_by(follow_id: other_user.id)
        relationship.destroy if relationship
    end

    def following?(other_user)
        self.followings.include?(other_user)
    end
    
    def feed_microposts
        Micropost.where(user_id: self.following_ids + [self.id])
    end
    
    def favorite(micropost)
        self.favorites.find_or_create_by(micropost_id: micropost.id)
    end

    def unfavorite(micropost)
        favorite = self.favorites.find_by(micropost_id: micropost.id)
        favorite.destroy if favorite
    end
    def favorited?(micropost)
        self.darling.include?(micropost)
    end
end

class CreateUsers < ActiveRecord::Migration[5.2]
  def change
    create_table :users do |t|
      t.string :name
      t.string :email
      t.string :password_digest

      t.timestamps
    end
  end
end

コード

Comments

[m.ts10806]

ルーティングとモデルの定義を提示してください。
今のところ・・「エラーの通り」になります。

[m.ts10806]

マイグレーションもあったほうがいいですね。

Answer 1

class UsersController < ApplicationController
end内に下記が記載されていないことが原因でした。
初歩的なミスで申し訳ありません。
def followings
@user = User.find(params[:id])
@followings = @user.followings.page(params[:page])
counts(@user)
end

def followers
@user = User.find(params[:id])
@followers = @user.followers.page(params[:page])
counts(@user)
end

private

def user_params
params.require(:user).permit(:name, :email, :password, :password_confirmation)
end