Ruby on Rails undefined方法`admin？' 为零：NilClass

Question

I am doing the web to support the guest user can view the coordinator list.

if admin login and go 'user_path'. admin can see all coordinator and able delete them.

if the guest views all the user. the guest can see all coordinator but cannot delete them.

_footer.html.erb

 <div class="footer-inquires"> 
    <div class="col-xs-6 col-md-3">
    <h5>General inquires</h5>
    <ul class="footer-links">
      <% User.all.each do |user| %>
        <li><%= link_to user.fname, user_path(user.id) %></li>  
      <% end %>

        <li><%= link_to "All", users_path %></li>

    </ul>  
  </div>

index.html.erb

<% provide(:title, 'All Coordinator | Course App') %>
<h1>All Coordinator</h1>

<%= will_paginate %>

<ul class="users">

  <%= render @users %>

</ul>

<%= will_paginate %>

_user.html.erb

<li>
  <%= gravatar_for user, size: 50 %>
  <%= link_to user.fname, user %>
  <% if current_user.admin? && !current_user?(user) %>
    | <%= link_to "delete", user, method: :delete,
                                  data: { confirm: "You sure?" } %>

  <%else%>

************************
what do i do  for else ?

***********************
  <% end %>

</li>

current error: guest(havent login) user can not view all users.

Showing /home/ec2-user/environment/course_app/app/views/users/_user.html.erb where line #4 raised:

undefined method `admin?' for nil:NilClass


 <%= gravatar_for user, size: 50 %>
  <%= link_to user.fname, user %>
  <% if current_user.admin? && !current_user?(user) %>
    | <%= link_to "delete", user, method: :delete,
                                  data: { confirm: "You sure to delete?" } %>

enter image description here

Answer 1

You can change your condition to if current_user && current_user.admin? && !current_user?(user) if current_user && current_user.admin? && !current_user?(user) .