Get UserID for Current User using Devise/Rails

Question

So I, a rails newbie, am currently trying to get the User ID from the current Devise session, and I am having a bit of trouble.

I have this in my controller now:

def index
  @currentUser = current_user.id
end

And I want to make a simple if statement to show/hide fields in my form.

<% if @currentUser === @product.user_id %>
          <%= link_to "Back", products_path %>
          <%= link_to "Edit", edit_product_path(@product) %>
          <%= link_to "Delete", product_path(@product), method: :delete, data: { confirm: "Are you sure?"} %>
      <% else %>
          <span></span>
<% end %>

I have a feeling my syntax in defining my currentUser variable is bad, but I have no idea how to fix this. There were a few similar questions on Stack, but none of them really applied to me or helped me.

Thanks in advance!

Answer 1

I see a few problems here

def index
  @currentUser = current_user.id
end

Other than what @HolyMoly already commented, you should use underscore and not camelcase, if current_user is nil here, .id will fail on it, resulting in an exception.

Second, you are checking "ability" by comparing values of ids, I would change your code to do this

<% if allow_product_delete?(@product) %>

In a helper

def allow_product_delete?(product)
  return false unless current_user
  @product.user_id == current_user.id
end

if you are using devise current_user exists in controller and views, you don't need to define it as an instance variable, it's already defined as a controller method on all actions (by default). so by calling current_user in your views you are done.

If a user is not logged in, current_user will be nil, you always have to prepare for this and protect against it.

Last, I would look into ability gems (cancan or cancancan), those provide a very nice DSL for dealing with what you were trying here.

Answer 2

Have you set it up to actually be able to user current_user ? in your code you have :

@currentUser = current_user.id

But where was current_user defined? I haven't used Devise but with sessions you could define the value of current_user with a helper method (you may be able to also do it right there in the sessions_controller #create method), like this:

 def current_user
     @current_user ||= User.find_by(id: session[:user_id])
  end

then throughout your app you could use current_user.id or current_user.name or whatever you needed.

So while sessions is not Devise, I hope this helps .