Customizing for different Invite use cases (emails etc.)

Sometimes you want to be able to send different invites for a variety of different reasons. Eg. Inviting a VIP user vs Inviting a regular user. Here is an example of doing it for a "friend" and for a "guest"

in your devise model, put

attr_writer :invitation_instructions

def deliver_invitation
 if @invitation_instructions
   ::Devise.mailer.send(@invitation_instructions, self).deliver
 else
   super
 end
end

def self.invite_guest!(attributes={}, invited_by=nil)
 self.invite!(attributes, invited_by) do |invitable|
   invitable.invitation_instructions = :guest_invitation_instructions
 end
end

def self.invite_friend!(attributes={}, invited_by=nil)
 self.invite!(attributes, invited_by) do |invitable|
   invitable.invitation_instructions = :friend_invitation_instructions
 end
end

From here if you run User.invite_guest! you should get an error that says that Devise::Mailer has no method such as guest_invitation_instructions.

The way to fix this is to create your own mailer class that inherits from Devise::Mailer, and create those methods yourself. EG.

class InviteMailer < Devise::Mailer

  def guest_invitation_instructions(record)
    devise_mail(record, :guest_invitation_instructions)
  end

  def friend_invitation_instructions(record)
    devise_mail(record, :friend_invitation_instructions)
  end

end

in your devise.rb add the line

config.mailer = "InviteMailer"

to make invite mailer your default class to send emails (wont override your other emails, which will still be sent by devise mailer)

Lastly, create your views in views/invite_mailer/guest_invitation_instructions and you should be all set!

NOTE: When you create custom mailer (for example "InviteMailer") old devise mailer views should be moved to new mailer directory (just copy files from /app/views/devise/mailer/ to /app/views/invite_mailer/).

Customizing email headers

Sometimes you might want to add a dynamic email header instead of pulling something statically from in config/locals. For example, a custom subject header. Here's an easy way to achieve just that.

Inside your "resource" (usually User) model:

class User < ActiveRecord::Base
  #... regular implementation ...
  
  # This method is called interally during the Devise invitation process. We are
  # using it to allow for a custom email subject. These options get merged into the
  # internal devise_invitable options. Tread Carefully.
  #
  def headers_for
    msg = "#{invited_by.full_name} has invited you to [Awesome Site]."
    action == :invitation_instructions ? { :subject => msg } : {}
  end
end