我正在使用omniauth-facebook gem，去的时候/auth/facebook我得到：
undefined method `path' for "https://graph.facebook.com":String
它让我发疯。
配置/初始化程序/omniauth.rb
Rails.application.config.middleware.use OmniAuth::Builder do
provider :facebook, [xxx], [xxx]
end
配置/路由.rb
match 'auth/:provider/callback', to: 'sessions#create'
match 'auth/failure', to: redirect('/')
我正在使用 1.9.2
完整的堆栈跟踪：
faraday (0.8.4) lib/faraday/connection.rb:191:in `url_prefix='
faraday (0.8.4) lib/faraday/connection.rb:40:in `initialize'
faraday (0.8.4) lib/faraday.rb:11:in `new'
faraday (0.8.4) lib/faraday.rb:11:in `new'
oauth2 (0.8.0) lib/oauth2/client.rb:51:in `connection'
oauth2 (0.8.0) lib/oauth2/client.rb:63:in `authorize_url'
oauth2 (0.8.0) lib/oauth2/strategy/auth_code.rb:18:in `authorize_url'
omniauth-oauth2 (1.1.1) lib/omniauth/strategies/oauth2.rb:48:in `request_phase'
omniauth-facebook (1.4.1) lib/omniauth/strategies/facebook.rb:94:in `request_phase'
omniauth (1.1.1) lib/omniauth/strategy.rb:207:in `request_call'
omniauth (1.1.1) lib/omniauth/strategy.rb:174:in `call!'
omniauth (1.1.1) lib/omniauth/strategy.rb:157:in `call'
omniauth (1.1.1) lib/omniauth/builder.rb:48:in `call'
任何帮助将不胜感激。