Question

I’m using omniauth-twitter and I have everything set up:

user.rb:

  def self.create_with_omniauth(auth)
    create! do |user|
      user.provider = auth["provider"]
      user.uid = auth["uid"]
      user.name = auth["info"]["name"]
      user.email = auth["info"]["email"]
      # To pass password validation
      user.password = user.password_confirmation = SecureRandom.urlsafe_base64(n=6) 
    end
  end

sessions_controller.rb:

 def create
    user = User.find_by_email(params[:session][:email].downcase)
    if user && user.authenticate(params[:session][:password])
      sign_in user
      redirect_back_or user
    else
      flash.now[:error] = 'Invalid email/password combination'
      render 'new'
    end
  end

The problem is that you can’t retrieve an email address from Twitter, so the login fails because of my validation rules:

user.rb:

 before_save { |user| user.email = email.downcase }
  before_save :create_remember_token

  validates :name, presence: true, length: { maximum: 50 }
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
  validates :email, presence:   true,
                    format:     { with: VALID_EMAIL_REGEX },
                    uniqueness: { case_sensitive: false }
  validates :password, presence: true, length: { minimum: 6 }
  validates :password_confirmation, presence: true 

I want to enable users to enter an email so they can login without failing the validation (only with Twitter, since I have Facebook and Google login too).

Does anyone have any suggestion?

EDIT:

users_controller.rb:

 def create
    @user = User.new(params[:user])
    if @user.save
      sign_in @user
      flash[:success] = "Welcome to the Sample App!"
      redirect_to @user
    else
      if params[:form_name] == "enter_email"
        render 'enter_email'
      else
        render 'new'
      end
    end
  end

users/enter_email.html.erb:

<% provide(:title, 'Enter your email') %>
<h1>Enter your email</h1>

    <div class="row">
      <div class="span6 offset3">
        <%= form_for(@user) do |f| %>
          <%= render 'shared/error_messages', object: f.object %>

          <%= f.label :email %>
          <%= f.text_field :email %>

          <%= f.hidden_field :provider, value: params[:oprovider] %>
          <%= f.hidden_field :provider, value: params[:oprovider] %>
          <%= f.hidden_field :uid, value: params[:ouid] %>
          <%= f.hidden_field :name, value: params[:oname] %>
          <%= f.hidden_field :password , value: params[:opassword] %>
          <%= f.hidden_field :password_confirmation, value: params[:opassword_confirmation] %>

          <% # To know to which form to redirect in case of validation error %>
          <%= hidden_field_tag 'form_name', 'enter_email' %>

          <%= f.submit "Create my account", class: "btn btn-large btn-primary" %>
        <% end %>
      </div>
    </div>

Answer 1

When the user is created it will be invalid since it will be missing the required email. So when the user save fails, you should put the information you retrieved from Twitter in the session and redirect the user to a registration page where he can input his email. Basically, this:

# SessionsController
def create

  if user.save
    sign_in user
    redirect_to ...
  else
    session[:omniauth] = request.env['omniauth.auth'].except('extra')
    redirect_to new_registration_path
  end

end

You’ll notice that we are discarding the extra hash because it usually contains a lot of information that we don’t need. If you do need it, be careful because the session has a certain size limit and sometimes you can’t fit everything in there.

Now you need to create a registrations controller with the new action (to show a page where the user will input his email) and the create action (where you will use the Twitter info to further customize your new user).

# RegistrationsController
def create
  if session[:omniauth]
    user = User.create_with_email_and_omniauth(params[:user], session[:omniauth])
  end
  session[:omniauth] = nil unless user.new_record?
end

Finally, if the user is valid and saved then we can safely destroy the Twitter info from the session.