Rails 4.0 的自定义错误处理

我正在使用 Ruby 2.0 和 Rails 4.0 构建 Ruby on Rails api。我的应用程序几乎只是一个 JSON API，因此如果发生错误（500、404），我想捕获该错误并返回格式良好的 JSON 错误消息。

我试过了this https://coderwall.com/p/w3ghqq并且：

rescue_from ActionController::RoutingError, :with => :error_render_method

def error_render_method
  puts "HANDLING ERROR"
  render :json => { :errors => "Method not found." }, :status => :not_found
  true
end

在我的应用程序控制器中。

这些都不起作用（根本没有捕获异常）。我的谷歌搜索显示，这在 3.1 和 3.2 之间发生了很大变化，而且我找不到任何关于如何在 Rails 4.0 中执行此操作的好的文档。

有人知道吗？

Edit这是我进入 404 页面时的堆栈跟踪：

Started GET "/testing" for 127.0.0.1 at 2013-08-21 09:50:42 -0400

ActionController::RoutingError (No route matches [GET] "/testing"):
actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0) lib/rails/engine.rb:511:in `call'
railties (4.0.0) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'


Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.0ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/routes/_route.html.erb (2.9ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/routes/_route.html.erb (0.9ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/routes/_table.html.erb (1.1ms)
Rendered /Library/Ruby/Gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/middleware/templates/rescues/routing_error.erb within rescues/layout (38.3ms)

我不认为我希望它走到这一步，应该有东西捕获它并返回适当的 json 错误响应。

该请求甚至没有到达您的应用程序。

您需要定义一个包罗万象的路由，以便 Rails 将请求发送到您的应用程序，而不是显示错误（在开发中）或呈现 public/404.html 页面（在生产中）

修改您的routes.rb文件以包含以下内容

match "*path", to: "errors#catch_404", via: :all

在你的控制器中

class ErrorsController < ApplicationController

  def catch_404
    raise ActionController::RoutingError.new(params[:path])
  end
end

和你的rescue_from那么应该捕获错误。