How to pass instance variable to devise custom mailer in Rails?

Question

I am using custom mailer by overriding the devise mailer. It is working fine. But I need to pass some data to the mailer template so that when the confirmation email send to the user it contains some dynamic content. I have tried it using sessions,@resource and current_user method but both are not working. Is there any way to do that? Custom mailer

class CustomMailer < Devise::Mailer
  helper :application # gives access to all helpers defined within `application_helper`.
  include Devise::Controllers::UrlHelpers # Optional. eg. `confirmation_url`
  default template_path: 'devise/mailer' # to make sure that you mailer uses the devise views

  def confirmation_instructions(record, token, opts={})
      opts[:subject] = "Email Confirmation"
      opts[:from] = 'no-reply@abc.com'
      @data = opts[:custom_field]
    super
  end

end

in the controller

CustomMailer.confirmation_instructions(token, {custom_field: "abc"})

This is the code in template

We are happy to invite you as user of the <b>  <%= @data %> </b>

Thanks.

Have you just edited confirmation email view or have you changed devise config to work with your mailer? — AntonTkachov, Nov 08 '17 at 16:43

Cyzanfar · Answer 1 · 2017-11-08T18:09:28.650

First, read about Devise custom mailer to familiarize yourself with the process.

Briefly this is how you'd go about doing it:

in config/initializers/devise.rb:

config.mailer = "DeviseMailer"

Now you can just use DeviseMailer like you'd do for any other mailer in your project:

    class DeviseMailer < Devise::Mailer   
      helper :application # gives access to all helpers defined within `application_helper`.
      include Devise::Controllers::UrlHelpers # Optional. eg. `confirmation_url`
      default template_path: 'devise/mailer' # to make sure that your mailer uses the devise views
     ...

    def invite(sender, recipient)
      @sender = sender
      @recipient = recipient

      mail( :to => recipient.email,
          :subject => "Invite by #{sender.name}"
        )
    end
      ...
   end

You can now call the invite in your project and pass whatever variable you want to be able to access in your template.

i.e:

Calling the invite method:

DeviseMailer.invite(current_user, newContact).deliver

So in your view you can then just call the variable:

invite.html.erb

<p>Hello <%= @recipient.email %></p>

<% if @sender.email? %>
  <p> some additional welcome text here from <%= @sender.email %> </p>
<% end %>

EDIT

To answer your specific question here is what you want to override:

def confirmation_instructions(record, token, opts={})
  headers["Custom-header"] = "Bar"
  opts[:from] = 'my_custom_from@domain.com'
  opts[:reply_to] = 'my_custom_from@domain.com'
  super
end

Then call it anywhere you want:

 DeviseMailer.confirmation_instructions(User.first, "faketoken", {})

thanks for your reply but devise controller send confirmation email on account creation. I have edited the question please have a look. — john, Nov 08 '17 at 18:07
It sure does. This is an example that shows how you can override the functions that devise defines. Here's an edit. — Cyzanfar, Nov 08 '17 at 18:08
Kindly look at my code and point out where I am wrong. I think I am doing right but not sure why it is not working. — john, Nov 08 '17 at 18:10
you are not sending any thing from controller. i cant find any thing sending from controller. — john, Nov 08 '17 at 18:12
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/158535/discussion-between-cyzanfar-and-john). — Cyzanfar, Nov 08 '17 at 18:13
Sir Please read my question I want to send variable/data from controller to mailer template. Is this clear? — john, Nov 08 '17 at 18:14

How to pass instance variable to devise custom mailer in Rails?

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