error-handling - 404、500 的自定义错误页面，但默认的 500 错误消息来自哪里？

Question

目前正在生产中，我收到以下文字:

500 Internal Server Error
If you are the administrator of this website, then please read this web application's
log file and/or the web server's log file to find out what went wrong.

该页面上没有任何 HTML。此代码位于何处？我没有 public/500.html 文件。
在我的 route ，我有:

  get "/404", :to => "errors#error_404"
  get "/422", :to => "errors#error_404"
  get "/500", :to => "errors#error_500"
  get "/505", :to => "errors#error_505"

错误 Controller :

class ErrorsController < ApplicationController

  def sub_layout
    "left"
  end

  def error_404
    render :status => 404, :formats => [:html], :layout => "white", :sub_layout => "left"
  end

  def error_422
    render :status => 422, :formats => [:html], :layout => "white", :sub_layout => "left"
  end

  def error_500
    render :status => 500, :formats => [:html], :layout => "white", :sub_layout => "left"
  end

  def error_505
    render :status => 505, :formats => [:html], :layout => "white", :sub_layout => "left"
  end

end

如何让它始终加载我的自定义错误？对于某些错误，它只会抛出来自 Ruby on Rails 核心某处的这两行文本。我希望它每次都能拾取我的自定义样式错误页面!

Answer 1

您遇到的错误是从
https://github.com/rails/rails/blob/4-0-stable/actionpack/lib/action_dispatch/middleware/show_exceptions.rb#L18-L22
这意味着您的异常被拯救的代码本身就是抛出异常。
您可以检查日志中的文本:Error during failsafe response:确定异常的真正来源，从而解决您的问题。