Rails 3，仅在用户登录时才呈现部分内容

Question

On a Rails 3.1 app, I have a method called user_logged_in? from Devise, which I want to use to render a partial selectively. Here's the code in layouts/application.html.erb:

<% if user_logged_in? %>
<%= render :partial => "home/statusbar" %>
<% end %>

It uses a partial from a different controller. This is the partial:

<div id="status_bar">  
  Signed in as <%= link_to current_user.name, edit_user_registration_path %>
</div>

An error occurs at current_user.name (undefined method), because current_user is nil . I could move the user_logged_in? check inside the partial, but I think it would be marginally more efficient if it were in the view.

Could you direct me to what the best practices are, or how I can overcome the undefined method error? Is it normal that Rails checks the code of the template even though it's in an if block that fails?

Answer 1

It looks like user_logged_in? is where something is going wrong.Does it work if you change to this?

<% if current_user.present? %>
  <%= render :partial => "home/statusbar" %>
<% end %>

Answer 2

I'm familiar with Devise, but not the user_logged_in? method - did you define it yourself? The normal helper used in views is user_signed_in? . Also, try something like the following:

<% puts user_logged_in?.inspect %>
<% puts user_signed_in?.inspect %>

Above the if statement in your view, and check your logs to make sure your call is returning false correctly ( user_signed_in? should also be returning false ). You should not be getting a nil error in that partial unless it is actually being rendered (meaning the code entered the if statement).

Answer 3

I found the solution, it appears that

user_logged_in?

Is not used anymore, and instead you need to use

user_signed_in?

So with the code you gave this should work:

<% if user_signed_in? %>
  <%= render :partial => "home/statusbar" %>
<% end %>

This code rendered a partial for me.

Answer 4

That code is being run, ruby is duck typed and dynamic, all checks are at runtime. So you need to check your conditional. Try

<% if false %>
  <%= render :partial => "home/statusbar" %>
<% end %>

and see if it stll fails. A bettter solution would be

<% if current_user %>
  <%= render :partial => "home/statusbar" %>
<% end %>

I am unfamiliar with devise but this should work Since current user wil be nil if nobody is logged in

Answer 5

There is an even shorter way to render your partial with a conditional

<%= render(partial: "home/statusbar") if current_user.present? %>