Rails Devise Send confirmation email after Facebook signup - ruby-on-rails

Question

Problem: How do I send the user an email after they sign up for the first time with Facebook? I'm using device and omniauth.
I have confirmation emails working for regular signup with devise. I need to send an email when the user gets added to my database for the first time after signing in with Facebook. Where in the code is this happening?
I tried adding a line of code sending the email in my omniauth_callbacks_controller.
class OmniauthCallbacksController < Devise::OmniauthCallbacksController
# omniauth_callbacks_controller
def facebook
#user = User.from_omniauth(request.env["omniauth.auth"])
facebook = "www.facebook.com"
if #user.persisted?
print "User persisted"
sign_in #user, :event => :authentication
set_flash_message(:notice,:success,:kind => "Facebook") if is_navigational_format?
# I SENT THE EMAIL HERE
else
session["device.facebook_data"] = request.env["omniauth.auth"]
redirect_to root_path
end
end
However, this just sends the user a confirmation email EVERY time they log in with Facebook, which is not what I want. I want to simply send the email the first time they log in.
The email should be sent in the registrations_controller. However, when users are signing up with Facebook, this controller is never used.
class RegistrationsController < Devise::RegistrationsController
def create
build_resource(sign_up_params)
if resource.save
if resource.active_for_authentication?
set_flash_message :notice, :signed_up if is_navigational_format?
sign_up(resource_name, resource)
# Tell the UserMailer to send a welcome email after save
UserMailer.welcome_email(current_user).deliver_later
return render :json => {:success => true}
else
set_flash_message :notice, :"signed_up_but_#{resource.inactive_message}" if is_navigational_format?
expire_session_data_after_sign_in!
return render :json => {:success => true}
end
else
clean_up_passwords resource
invalid_signin_attempt
end
end
Would like to know the right way to send a confirmation to the user after signing up with Facebook.

Answer 1

Problem
It looks like your User.from_omniauth function behaves like a find_or_create call. That means that the controller has no knowledge of whether the user was just created or is being fetched from an existing identity in the database.
If the user is created as part of this from_omniauth call, then you should be able to just rely on the Devise :confirmable module. Otherwise, the user is created before you get back the OAuth credentials, so you need to handle it manually.
The code in the from_omniauth function likely looks something like this:
def self.from_omniauth(token)
user = User.find(token: token)
if user.nil?
user = User.create(token: token, ...)
# ...
end
# ...
end
There might be an intermediary Token, Identity, or other such class, but the logic should be the same.
Fix
There are two easy ways to fix this:
Include a created boolean as part of the from_omniauth return value, which the controller can then use to gate the confirmation email on.
Move the "create" part of the "find or create" logic out into the controller, so that the email can be sent as part of the "create" path.
Aside
Also, I'd suggest using the Devise resource.send_confirmation_instructions function and piggybacking your email off that. That way, all welcome emails share the same code and you're not maintaining a separate module just for Facebook/OAuth login.