Devise form within a different controller

Question

I am using a devise gem for sign_in/sign_out procedures.

I generated views files from devise, using rails g devise views

I saw there was a devise/sessions/new.html.erb file which contained a form for sign_in.

I created another file devise/sessions/_form.html.erb and did <%= render 'form' %> within a new.html.erb file, and that worked out very fine.

Now, I wanted to include this form from the different controller. So in a controller called 'main', (specifically, within view page) 'mains/index.html.erb' I included <%= render 'devise/sessions/form' %> file. It seems that inclusion worked fine, but I am getting the following error.

NameError in Mains#index

Showing /home/administrator/Ruby/site_v4_ruby/app/views/devise/sessions/_form.html.erb where line #1 raised:

undefined local variable or method `resource' for #<#<Class:0x007f1aa042d530>:0x007f1aa042b870>
Extracted source (around line #1):

1: <%= form_for(resource, :as => resource_name, :url => session_path(resource_name)) do |f| %>
2:   <p><%= f.label :email %><br />
3:   <%= f.text_field :email %></p>
4: 

It seems that form_for(resource,...) part is causing the problem (which works fine if I am on the original devise sign_in page... How can I resolve this problem in rails way?

I personally prefer to use 'render' function to include the form, rather than writing html codes inline.

Do I have to specify something (resource) within the 'main' controller?

I will appreciate your help. Thank you.

Answer 1

As Andres says, the form calls helpers which are specified by Devise and so aren't present when you access a Devise form from a non-Devise controller.

To get around this, you need to add the following methods to the helper class of the controller you wish to display the form under. Alternatively, you can just add them to your application helper to make them available anywhere.

  def resource_name
    :user
  end

  def resource
    @resource ||= User.new
  end

  def devise_mapping
    @devise_mapping ||= Devise.mappings[:user]
  end

Source: http://pupeno.com/blog/show-a-devise-log-in-form-in-another-page/