self.from_omniauth(auth, organisation) REFACTOR

refactor_from_omniaut.rb

# 3. Please refactor User#from_omniauth method. Currently it's hard to read. Please make it more clear.


def self.from_omniauth(auth, organization)
    user = User.where(provider: auth.provider, uid: auth.uid).first
    if user
      return user
    else
      registered_user = User.where(email: auth.info.email).first
      if registered_user
        return registered_user
      else
        user = User.create(
          provider: auth.provider,
          uid: auth.uid,
          name: auth.info.name,
          email: auth.info.email,
          password: Devise.friendly_token[0, 20],
          organization: organization
        )
      end
    end
  end


# 1st refactor 

def self.from_omniauth(auth, organization)
  user = User.where(provider: auth.provider, uid: auth.uid).first
  registered_user = User.where(email: auth.info.email).first

  return user if user
  return registered_user if registered_user
  User.create(
    provider: auth.provider,
    uid: auth.uid,
    name: auth.info.name,
    email: auth.info.email,
    password: Devise.friendly_token[0, 20],
    organization: organization
  )
end

3rd Version

class OmniauthUser
  attr_reader :auth, :organization

  def self.initialize(auth, organization)
    @auth = auth
    @organization = organization
  end
  ## this initialise does not work

  def self.find_or_create(auth, organization)
    omniauth_user = User.where(provider: auth.provider, uid: auth.uid).first
    registered_user = User.where(email: auth.info.email).first


    return omniauth_user if omniauth_user
    return registered_user if registered_user
    create_ominauth_user(auth, organization)
  end

  private

  # def self.omniauth_user(auth, organization)
  #   @omniauth_user ||= User.where(provider: auth.provider, uid: auth.provider).first
  # end
  #
  # def self.registered_user(auth, organization)
  #   @registered_user ||= User.where(email: auth.info.email).first
  # end

  def self.create_ominauth_user(auth, organization)
    User.create(
       provider: auth.provider,
       uid: auth.uid,
       name: auth.info.name,
       email: auth.info.email,
       password: Devise.friendly_token[0, 20],
       organization: organization
   )
  end
end

Final code

class OmniauthUser
  attr_reader :auth, :organization

  def initialize(auth, organization)
    @auth = auth
    @organization = organization
  end

  def find_or_create
    if omniauth_user
      omniauth_user
    elsif registered_user
      registered_user
    else
      create_omniauth_user
    end
  end

  private

  def omniauth_user
    User.where(provider: auth.provider, uid: auth.uid).first
  end

  def registered_user
    User.where(email: auth.info.email).first
  end

  def create_omniauth_user
    User.create(
       provider: auth.provider,
       uid: auth.uid,
       name: auth.info.name,
       email: auth.info.email,
       password: Devise.friendly_token[0, 20],
       organization: organization
   )
  end
end

Saw your question on gitter, any reason why you aren't simply using the default in the Devise README on OmniAuth?