Connect Twitter Account to existing Devise Account

Question

A user can register through Devise.

After the registration a User should be able to connect his

• Twitter Account

In the past i used omniauth to get facebook and twitter connect working. But in this particular Situation i need to LINK a twitter account to an existing Devise Account.

Can anyone give me a helping hand on where to start or read, i'm completely clueless.

Answer 1

gems

gem 'omniauth-twitter'
gem 'omniauth-facebook'
gem 'omniauth-linkedin'

in views

<%= check_connection('Facebook')%>
<%= check_connection('Linkedin')%>
<%= check_connection('Twitter')%>

helpers

  def check_connection(provider)
    if current_user.has_connection_with(provider)
      html = link_to disconnect_path(social: provider.downcase), class: "#{provider}-m phone-verified row" do
        content_tag :span, 'Verified', class: "verified"
      end
    else
      html = link_to user_omniauth_authorize_path(provider: provider.downcase), class: "#{provider}-m phone-verified row" do
        content_tag :span, 'Click to verify', class: "un-verified"
      end
    end
  end

in user model - for you this might be different

  devise :database_authenticatable, :registerable, :confirmable, :lockable,
         :recoverable, :rememberable, :trackable, :validatable, :omniauthable,
         :omniauth_providers => [:facebook, :twitter, :linkedin]

  has_many :authorizations, :dependent => :destroy

  def has_connection_with(provider)
    auth = self.authorizations.where(provider: provider).first
    if auth.present?
      auth.token.present?
    else
      false
    end
  end

in routes I have

  devise_for :users, :controllers => {:registrations => "users/registrations",
    :sessions => "users/sessions",
    :passwords => "users/passwords",
    :omniauth_callbacks => "users/omniauth_callbacks" #<- this one you need
  }

create authorization table - see this link uninitialized constant User::Authorization | omniauth

class CreateAuthorizations < ActiveRecord::Migration
  def change
    create_table :authorizations do |t|
      t.string :provider
      t.string :uid
      t.integer :user_id
      t.string :token
      t.string :secret
      t.string :first_name
      t.string :last_name
      t.string :name
      t.string :link

      t.timestamps
    end
  end
end

OmniauthCallbacksController /controllers/users/...

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController

  require 'uuidtools'

  def facebook
    oauthorize "Facebook"
  end

  def twitter
    oauthorize "Twitter"
  end

  def linkedin
    oauthorize "LinkedIn"
  end

  def passthru
    render :file => "#{Rails.root}/public/404.html", :status => 404, :layout => false
  end

private

  def oauthorize(kind)
    @user = find_for_ouath(kind, env["omniauth.auth"], current_user)
    if @user
      flash[:notice] = I18n.t "devise.omniauth_callbacks.success", :kind => kind
      session["devise.#{kind.downcase}_data"] = env["omniauth.auth"]
      sign_in_and_redirect @user, :event => :authentication
    end
  end

  def find_for_ouath(provider, access_token, resource=nil)
    user, email, name, uid, auth_attr = nil, nil, nil, {}
    case provider
      when "Facebook"
        uid = access_token['uid']
        email = access_token['info']['email']
        auth_attr = { :uid => uid, :token => access_token['credentials']['token'],
          :secret => nil, :first_name => access_token['info']['first_name'],
          :last_name => access_token['info']['last_name'], :name => access_token['info']['name'],
          :link => access_token['extra']['raw_info']['link'] }
      when "Twitter"
        uid = access_token['extra']['raw_info']['id']
        name = access_token['extra']['raw_info']['name']
        auth_attr = { :uid => uid, :token => access_token['credentials']['token'],
          :secret => access_token['credentials']['secret'], :first_name => access_token['info']['first_name'],
          :last_name => access_token['info']['last_name'], :name => name,
          :link => "http://twitter.com/#{name}" }
      when 'LinkedIn'
        uid = access_token['uid']
        name = access_token['info']['name']
        auth_attr = { :uid => uid, :token => access_token['credentials']['token'],
          :secret => access_token['credentials']['secret'], :first_name => access_token['info']['first_name'],
          :last_name => access_token['info']['last_name'],
          :link => access_token['info']['public_profile_url'] }
    else
      raise 'Provider #{provider} not handled'
    end
    if resource.nil?
      if email
        user = find_for_oauth_by_email(email, resource)
      elsif uid && name
        user = find_for_oauth_by_uid(uid, resource)
        if user.nil?
          user = find_for_oauth_by_name(name, resource)
        end
      end
    else
      user = resource
    end

    auth = user.authorizations.find_by_provider(provider)
    if auth.nil?
      auth = user.authorizations.build(:provider => provider)
      user.authorizations << auth
    end
    auth.update_attributes auth_attr

    return user
  end

  def find_for_oauth_by_uid(uid, resource=nil)
    user = nil
    if auth = Authorization.find_by_uid(uid.to_s)
      user = auth.user
    end
    return user
  end

  def find_for_oauth_by_email(email, resource=nil)
    if user = User.find_by_email(email)
      user
    else
      user = User.new(:email => email, :password => Devise.friendly_token[0,20])
      user.save
    end
    return user
  end

  def find_for_oauth_by_name(name, resource=nil)
    if user = User.find_by_name(name)
      user
    else
      first_name = name
      last_name = name
      user = User.new(:first_name => first_name, :last_name => last_name, :password => Devise.friendly_token[0,20], :email => "#{UUIDTools::UUID.random_create}@host")
      user.save(:validate => false)
    end
    return user
  end

end