一直很想试下 omniauth
我很菜，找到了这篇文章 http://railscasts.com/episodes/241-simple-omniauth 按其过程一路下来，注册好'CONSUMER_KEY', 'CONSUMER_SECRET'
最后 rake routes 时，说不能初始化:
uninitialized constant OmniAuth::Strategies::Twitter
查到原因是还要添加 omniauth-twitter 这个 gem
gem 'omniauth-twitter'
这时，rake routes 时： ``` /auth/:provider/callback(.:format) {:controller=>"sessions", :action=>"create"} signout /signout(.:format) {:controller=>"sessions", :action=>"destroy"}
当我访问http://localhost:3000/auth/twitter 时，成功跳转到twitter去登录，登录成功后返回时，出错：
```Started GET "/auth/twitter/callback?oauth_token=1RubhwlvzjEE9mfYIGiKD1ZIGUNBDFqgkLfV4jo6bU&oauth_verifier=OEUA0qLLZNpYunwDL1BnWSydCo4IbnUYqOCTzZ33goo" for 127.0.0.1 at 2011-11-26 22:32:30 +0800
Processing by SessionsController#create as HTML
Parameters: {"oauth_token"=>"1RubhwlvzjEE9mfYIGiKD1ZIGUNBDFqgkLfV4jo6bU", "oauth_verifier"=>"OEUA0qLLZNpYunwDL1BnWSydCo4IbnUYqOCTzZ33goo", "provider"=>"twitter"}
User Load (0.5ms) SELECT `users`.* FROM `users` WHERE `users`.`provider` = 'twitter' AND `users`.`uid` = '18209844' LIMIT 1
Completed 500 Internal Server Error in 71ms
Started GET "/auth/failure?message=invalid_response" for 127.0.0.1 at 2011-11-26 22:32:34 +0800
ActionController::RoutingError (No route matches [GET] "/auth/failure"):
原因我查了很久，一直以为是 twtter 处配置的问题，后来，看了 log，请求已经成功返回，带有验证后的数据，问题出在 ```user = User.find_by_provider_and_uid(auth["provider"], auth["uid"]) || User.create_with_omniauth(auth)
继续log往下找时，在User中的create_with_omniauth方法中，看到有auth["provider"]，auth["uid"]以及auth["user_info"]["name"]，
好吧，我将auth打印出来，我找到了provider，uid，就是找不到user_info，但我找到了name...
我觉得我已经找到问题所在，auth["user_info"]["name"] 修改成 auth["name"] 后，重试果然成功
