Devise + Omniauth + Oauth2 +（豆瓣、QQ、微博）

devise_omniauth_oauth2_tqq_douban_weibo.rb

=begin
参考教程：http://www.douban.com/note/411359006/
Gem Omniauth(https://github.com/intridea/omniauth)
Gem omniauth-oauth2 (https://github.com/intridea/omniauth-oauth2)
流程参考：https://ruby-china.org/topics/6464
Devise and OmniAuth (revised) (http://railscasts.com/episodes/235-devise-and-omniauth-revised)
=end

# Gem lists

  gem 'devise'
  gem 'omniauth'
  gem 'omniauth-oauth2'

# add three strategies
C:\Sites\tm_wed\lib\omniauth\strategies\douban.rb (https://gist.github.com/krongk/21f3bbc7a38085883a2c)
C:\Sites\tm_wed\lib\omniauth\strategies\tqq.rb (https://gist.github.com/krongk/22bc15da7bd37ea9f7ad)
C:\Sites\tm_wed\lib\omniauth\strategies\weibo.rb (https://gist.github.com/krongk/aedf1566ad6a8ffdba9f)

#config devise
# C:\Sites\tm_wed\config\initializers\devise.rb:

  require 'omniauth/strategies/tqq'
  require 'omniauth/strategies/douban'
  require 'omniauth/strategies/weibo'
  ...
  config.omniauth :tqq, ENV['TQQ_KEY'], ENV['TQQ_SECURT']
  config.omniauth :douban, ENV['DOUBAN_KEY'], ENV['DOUBAN_SECURT']
  config.omniauth :weibo, ENV['WEIBO_KEY'], ENV['WEIBO_SECURT']
  
#config model
# C:\Sites\tm_wed\app\models\user.rb:
# changes log:
#  . add :omniauthable
#  . add helper methods

  class User < ActiveRecord::Base
    rolify
    devise :database_authenticatable, :registerable, :omniauthable,
           :recoverable, :rememberable, :trackable, :validatable
  
    has_many :sites, -> { order("updated_at DESC") }, :dependent => :destroy
  
    def self.from_omniauth(auth)
      where(auth.slice(:provider, :uid)).first_or_create do |user|
        user.provider = auth.provider
        user.uid = auth.uid
        user.name = auth.info.nickname
      end
    end
  
    def self.new_with_session(params, session)
      if session["devise.user_attributes"]
        new(session["devise.user_attributes"], without_protection: true) do |user|
          user.attributes = params
          user.valid?
        end
      else
        super
      end
    end
  
    def password_required?
      super && provider.blank?
    end
  
    def update_with_password(params, *options)
      if encrypted_password.blank?
        update_attributes(params, *options)
      else
        super
      end
    end
  
  end
  
#rake migration
# edit uid from int to bigint

  class AddOmniauthToUsers < ActiveRecord::Migration
    def change
      add_column :users, :provider, :string
      add_column :users, :uid, :integer
    end
  end

#update routes
# 修改routes.rb, 主要是指明回调方法路径
  devise_for :users, :controllers => {:registrations => "registrations", omniauth_callbacks: "omniauth_callbacks"}
  
#create callback controller
# C:\Sites\tm_wed\app\controllers\omniauth_callbacks_controller.rb:

  class OmniauthCallbacksController < Devise::OmniauthCallbacksController
     #skip CSRF on create.
    skip_before_filter :verify_authenticity_token
  
    def all
      user = User.from_omniauth(request.env["omniauth.auth"])
      if user.persisted?
        sign_in_and_redirect user, notice: '登录成功'
      else
        session["devise.user_attributes"] = user.attributes
        redirect_to new_user_registration_url
      end
    end
  
    alias_method :tqq, :all
    alias_method :douban, :all
    alias_method :weibo, :all
  end

#config views
# C:\Sites\tm_wed\app\views\devise\registrations\new.html.erb:
  
  <h3>注册账户</h3>
  <%= simple_form_for(resource, :as => resource_name, :url => registration_path(resource_name), :html => { :role => 'form'}) do |f| %>
   
    ...
  
    <% if f.object.password_required? %>
      <div class="form-group col-md-6">
        <%= f.label :password %>
        <%= f.password_field :password, class: 'required form-control' %>
      </div>
      <div class="form-group col-md-6">
        <%= f.label :password_confirmation %>
        <%= f.password_field :password_confirmation, class: 'required form-control' %>
      </div>
    <% end %>
     <%= f.submit '提 交 注 册', :class => 'btn btn-meflat' %>
  <% end %>

# C:\Sites\tm_wed\app\views\devise\registrations\edit.html.erb:

  <h3>修改账户</h3>
  <%= form_for(resource, :as => resource_name, :url => registration_path(resource_name), :html => { :method => :put, :role => 'form'}) do |f| %>
    ...
    <% if f.object.encrypted_password.present? %>
      <fieldset>
        <div class="form-group">
          <%= f.label :current_password %>
          <%= f.password_field :current_password, class: 'form-control' %>
        </div>
      </fieldset>
    <% end %>
    
    <%= f.submit '修 改', :class => 'button right' %>
  <% end %>

# C:\Sites\tm_wed\app\views\devise\sessions\new.html.erb:

  <div>
    <%= link_to "QQ账号登录",  user_omniauth_authorize_path(:tqq) %>  |
    <%= link_to "豆瓣账号登录",  user_omniauth_authorize_path(:douban) %> |
    <%= link_to "微博账号登录",  user_omniauth_authorize_path(:weibo) %>
  </div>