仅在未在

Question

我正在建立一个包含分层管理员权限的博客。当我使用我们的种子管理员帐户登录时，我可以看到索引就好了。当我转到未登录的页面时，应该由before_action过滤的内容我收到错误，说明未定义的方法`admin =＆＃39; for nil：我的索引视图中的NilClass。

当我没有登录时，current_user应为nil，视图中的if语句应解析为false。代码片段供参考，如下所示。

以下是观点：

<div id="blog">

<%= render 'blogs/blog_header' %>

<div class="messages">
    <%= render 'layouts/flash_messages' %>
</div>

<%= will_paginate @bloggers %>

<% @bloggers.each do |blogger| %>
    <div class="post_wrapper">
        <h2 class="title"><%= blogger.name %></h2>
        <p class="date_and_author" style="display:inline"><%= blogger.email %></p>
        <% if current_blogger.admin = 1 %>
        <p class="date_and_author" style="display:inline">||</p>
        <button class="button" style="display:inline"><%= link_to "delete", blogger, method: :delete,
                                          data: { confirm: "You sure?" } %></button>
        <% end %>
    </div>
<% end %>

<%= will_paginate %>

控制器：

class BloggersController < ApplicationController
before_action :signed_in_blogger, only: [:show, :edit, :update, :destroy]

# GET /bloggers
# GET /bloggers.json
def index
  @bloggers = Blogger.paginate(page: params[:page], per_page: 20)
end

# GET /bloggers/1
# GET /bloggers/1.json
def show
  @blogger = Blogger.find(params[:id])
end

# GET /bloggers/new
def new
  @blogger = Blogger.new
end

# GET /bloggers/1/edit
def edit
end

# POST /bloggers
# POST /bloggers.json
def create
  @blogger = Blogger.new(blogger_params)
    if @blogger.save
      blog_sign_in @Blogger
        flash.now[:success] = "New account successfully created."
      redirect_to "/blogs"
  else
    render 'new'
  end
end

# PATCH/PUT /bloggers/1
# PATCH/PUT /bloggers/1.json
def update
  respond_to do |format|
    if @blogger.update(blogger_params)
        format.html { redirect_to @blogger, notice: 'User was successfully updated.' }
        format.json { render :show, status: :ok, location: @blogger }
    else
        format.html { render :edit }
        format.json { render json: @blogger.errors, status: :unprocessable_entity }
    end
  end
end

# DELETE /bloggers/1
# DELETE /bloggers/1.json
def destroy
  Blogger.find(params[:id]).destroy
    respond_to do |format|
    format.html { redirect_to bloggers_url, notice: 'User was successfully destroyed.' }
    format.json { head :no_content }
  end
end

private

def blogger_params
    params.require(:blogger).permit(:name, :email, :password, :admin, :password_confirmation)
end

# Confirms a signed-in user
def signed_in_blogger
    unless blog_signed_in?
        flash[:error] = "Please sign in."
        redirect_to blog_signin_path
      end
   end
end

帮助者：

 # Logs in the given blogger
def blog_sign_in(blogger)
    session[:blogger_id] = blogger.id
end

# Returns the current logged-in blogger (if any)
def current_blogger
    @current_blogger ||= Blogger.find_by(id: session[:blogger_id])
end

# Returns true if the blogger is logged in, false otherwise.
def blog_signed_in?
    !current_blogger.nil?
end

def blog_sign_out
    session[:blogger_id] = nil
    @current_blogger = nil
end

这可能与某个单独的错误有关，在这个错误中，当我尝试创建一个新的博客时，在点击创建之后，我得到了nil的未定义方法ID：Class？＆＃34;任何帮助将不胜感激。

根据请求粘贴博客模型：

class Blogger < ActiveRecord::Base
attr_accessible :name, :email, :password, :password_confirmation, :admin, :remember_token
has_secure_password

before_save { self.email = email.downcase }
before_create :create_remember_token
validates :name, presence: true, length: { maximum: 50 }
VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
validates :email, presence: true, format: { with: VALID_EMAIL_REGEX }, uniqueness: true
validates :password, length: { minimum: 5 }
validates :password_confirmation, presence: true

def Blogger.new_remember_token
  SecureRandom.urlsafe_base64
end

def Blogger.digest(token)
  Digest::SHA1.hexdigest(token.to_s)
end

private

def create_remember_token
    self.remember_token = Blogger.digest(Blogger.new_remember_token)
end
end

Answer 1

如果您没有登录，而current_blogger正如您所说的那样nil，则admin将不是可用的方法。要避免此错误，请将视图中的if语句更改为此类。

<% if current_blogger && current_blogger.admin == 1 %>

您还可以使用try方法，该方法也可以使用

<% if current_blogger.try(:admin) == 1 %>