Facebook令牌到期和更新,与考拉和omniauth-facebook

Question

我正在编写一个Rails应用程序,该应用程序使用omniauth-facebook来针对FB对用户进行身份验证(以及为用户获取FB OAuth访问令牌).然后,应用程序使用Koala使用保存的OAuth令牌对FB Graph API进行各种调用.

每次用户重新进行身份验证时(通常在他们登录我的应用程序时),我都会更新已保存的令牌.即便如此,保存的令牌也会不时到期(或以其他方式变为无效).

在使用考拉时,防止身份验证失败和更新令牌的最佳做法是什么？

是否所有调用都包含在begin/rescue块中,并使用异常处理程序对FB进行重新验证？

是否有某种方式(使用Koala)来利用此处描述的"扩展访问令牌"流程？如果没有,是否有编写自己的代码以从Koala调用中自己提取新令牌的最佳实践？

Answer 1

我所拥有的是在每个需要活动的Facebook会话的页面上触发的before_filter.这样的事情应该有效:

  before_filter :reconnect_with_facebook
  def reconnect_with_facebook
    if current_account && current_account.token_expired?(session[:fb]["expires"])

    # re-request a token from facebook. Assume that we got a new token so
    # update it anyhow...
    session[:return_to] = request.env["REQUEST_URI"] unless request.env["REQUEST_URI"] == facebook_request_path
    redirect_to(with_canvas(facebook_request_path)) and return false
  end
end

token_expired？方法看起来像这样:

def token_expired?(new_time = nil)
  expiry = (new_time.nil? ? token_expires_at : Time.at(new_time))
  return true if expiry < Time.now ## expired token, so we should quickly return
  token_expires_at = expiry
  save if changed?
  false # token not expired. :D
end

Answer 2

我发现这篇文章改编了Facebook上Railscast的代码,以展示如何为60天的代码交换短期代币:

user.rb

 def self.from_omniauth(auth)

    # immediately get 60 day auth token
    oauth = Koala::Facebook::OAuth.new(ENV["FACEBOOK_APP_ID"], ENV["FACEBOOK_SECRET"])
    new_access_info = oauth.exchange_access_token_info auth.credentials.token

    new_access_token = new_access_info["access_token"]
    # Facebook updated expired attribute
    new_access_expires_at = DateTime.now + new_access_info["expires_in"].to_i.seconds

    where(auth.slice(:provider, :uid)).first_or_initialize.tap do |user|
      user.provider = auth.provider
      user.uid = auth.uid
      user.name = auth.info.name
      user.image = auth.info.image
      user.email = auth.info.email
      user.oauth_token = new_access_token #originally auth.credentials.token
      user.oauth_expires_at = new_access_expires_at #originally Time.at(auth.credentials.expires_at)
      user.save!
    end
  end