Ominauth callback

(registration)new.html.slim

h2 Sign up
= simple_form_for(resource, :as => resource_name, :url => registration_path(resource_name)) do |f|
  = f.error_notification
  .form-inputs
    = f.input :email, :required => true, :autofocus => true
    = f.input :username, :required => true
  .form-actions
    = f.button :submit, "Sign up"
/= render "devise/shared/links"

(sessions)new.html.slim

h2 登陆
= render "devise/shared/links"

devise.rb

  config.omniauth :github, '28a2b6dcbc0e8f9ff508', 'dcd93b0761c98ae14dd9bd1836df6e1502b2bcd4'
  config.omniauth :weibo, "1840943522", "c6f4524f70db2e237e7a0cc015f2f176"

omniauth_callbacks_controller.rb

class OmniauthCallbacksController < Devise::OmniauthCallbacksController
  def all
    user = User.from_omniauth request.env["omniauth.auth"]

    if user.persisted?
      # logger.warn "------------------->yes"
      sign_in_and_redirect user, notice: "欢迎您登陆"
    else
      # logger.warn "------------------->no"
      session['devise.user_attributes'] = user.attributes
      redirect_to new_user_registration_url
    end
  end

  alias_method :github, :all
  alias_method :weibo, :all
end

user.rb

# == Schema Information
#
# Table name: users
#
#  id                     :integer          not null, primary key
#  email                  :string(255)      default(""), not null
#  encrypted_password     :string(255)      default(""), not null
#  reset_password_token   :string(255)
#  reset_password_sent_at :datetime
#  remember_created_at    :datetime
#  sign_in_count          :integer          default(0)
#  current_sign_in_at     :datetime
#  last_sign_in_at        :datetime
#  current_sign_in_ip     :string(255)
#  last_sign_in_ip        :string(255)
#

class User < ActiveRecord::Base

  devise :database_authenticatable, :registerable, :recoverable,
    :rememberable, :trackable, :validatable, :omniauthable

  attr_accessible :username, :encrypted_password, :email

  validates :username, presence: true, uniqueness: true

  def self.from_omniauth(auth)
    where(auth.slice(:provider, :uid)).first_or_create do |user|
      user.provider = auth.provider
      user.uid = auth.uid
      user.username = auth.info.nickname
      user.email = auth.info.email
    end
  end

  # Allocate the new session for the user
  def self.new_with_session(params, session)
    if session["devise.user_attributes"]
      new(session["devise.user_attributes"]) do |user|
        user.attributes = params
        user.valid?
      end
    else
      super
    end
  end

  # Tell whether the user need a password. basically it is a overidden function.
  def password_required?
    false
  end

  def sign_up_params
     params.require(:user).permit(:email, :username)
  end
end