使用RoR在facebook上弃用了offline_access

Question

我们的RoR应用程序存在问题.我们正在使用omniauth的facebook身份验证,并使用Koala搜索用户朋友.但是最近,当我们尝试显示朋友照片时,我们收到了此错误:

Koala::Facebook::APIError in Homes#show

Showing /home/daniel/Homes/app/views/shared/_event.html.erb where line #19 raised:

OAuthException: Error validating access token: Session has expired at unix time 1328727600. The current unix time is 1328802133.
Extracted source (around line #19):

16:     <img src="../assets/friends-icon.png" alt="User  profile apicture" height="33" width="43">
17:         <% if current_user %>
18:           <% event.friends_in_event(@person).each do |f| %>
19:             <%= link_to(image_tag(f.fb_picture, :size => "43x33"), person_path(f.id)) %>
20:           <% end %>
21:         <% end %>
22:       </div>

身份验证工作正常,但Facebook已经弃用了offline_access选项,这项工作正常,但现在,我们遇到了这个问题.是扩展access_token？的任何方式,还是有另一种解决方案？

这是我们的omniauth.rb

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :facebook, ENV['FB_KEY'], ENV['FB_SECRET'], 
  { :scope => 'email,offline_access,user_photos,publish_stream',
    :client_options => { :ssl => { :ca_path => "/etc/ssl/certs" } } }
end

还有我们的koala.rb

Koala.http_service.http_options = {
  :ssl => { :ca_path => "/etc/ssl/certs" }
}

提前致谢.

Answer 1

这个问题有两个解决方案:

• 扩展用户的访问令牌:
  • 根据Facebook文档中的这篇文章,您可以要求对用户的访问令牌进行60天的延期.但是,如果用户未在该时间段内返回,则此方法无法帮助您.
  • 您可以在此StackOverflow问题中找到一个PHP代码段来执行此操作.
    1. 为此,请向此API端点发送帖子: https://graph.facebook.com/oauth/access_token?client_id=APP_ID&client_secret=APP_SECRET&grant_type=fb_exchange_token&fb_exchange_token=EXISTING_ACCESS_TOKEN

• 捕获OAuthException并请求新的访问令牌:
  • Facebook提供了一个PHP代码片段,在他们的开发博客上概述了这个解决方案.
  • 基本上,您按照以下步骤操作:
    1. 用用户当前的图表调用图表access_token.
    2. 如果通话成功,那access_token很好.如果它抛出一个OAuthException,则将用户重定向到https://www.facebook.com/dialog/oauth?client_id=APP_ID&redirect_uri=CALLBACK_URL
    3. 用户将被发送到URL,然后重定向到您CALLBACK_URL用code的参数.
    4. 发送帖子到以下网址,code以获取新的access_token:https://graph.facebook.com/oauth/access_token?client_id=APP_ID&redirect_uri=CALLBACK_URL&client_secret=APP_SECRET&code=CODE&display=popup

阅读他们的开发博客上的帖子了解更多信息.

编辑(添加示例Ruby on Rails代码):

将以下内容添加到您的顶部ApplicationController:

rescue_from Koala::Facebook::APIError, :with => :handle_fb_exception

将以下protected方法添加到您的ApplicationController:

def handle_fb_exception exception
  if exception.fb_error_type.eql? 'OAuthException'
    logger.debug "[OAuthException] Either the user's access token has expired, they've logged out of Facebook, deauthorized the app, or changed their password"
    oauth = Koala::Facebook::OAuth.new

    # If there is a code in the url, attempt to request a new access token with it
    if params.has_key? 'code'
      code = params['code']
      logger.debug "We have the following code in the url: #{code}"
      logger.debug "Attempting to fetch a new access token..."
      token_hash = oauth.get_access_token_info code
      logger.debug "Obtained the following hash for the new access token:"
      logger.debug token_hash.to_yaml
      redirect_to root_path
    else # Since there is no code in the url, redirect the user to the Facebook auth page for the app
      oauth_url = oauth.url_for_oauth_code :permissions => 'email'
      logger.debug "No code was present; redirecting to the following url to obtain one: #{oauth_url}"
      redirect_to oauth_url
    end
  else
    logger.debug "Since the error type is not an 'OAuthException', this is likely a bug in the Koala gem; reraising the exception..."
    raise exception
  end
end

Koala调用全部取自以下2个教程:

• https://github.com/arsduo/koala/wiki/OAuth
• https://github.com/arsduo/koala/wiki/Koala-on-Rails