如何在 Rails3 中使用机架中间件? [英] How to use rack middleware with Rails3?

问题描述

大家好，我正在尝试制作机架中间件 NotFound 与 rails3 一起工作，但我需要进行一些更改以返回一些 json，所以我基本上定义了一个新类:

Hey guys, I'm trying to make the rack middleware NotFound to work with rails3 but I needed to make some changes to return some json, so I basically defined a new class :

class NotFound

  def initialize(app, msg, content_type = "text/html")
    @app = app
    @content = msg
    @length = msg.size.to_s
    @content_type = content_type
  end

  def call(env)
    [404, {'Content-Type' => @content_type, 'Content-Length' => @length}, @content]
  end
end

我将上面的这个类添加到app/middleware/not_found.rb"并将下面的这一行添加到我的 application.rb 文件中:

I added this class above to "app/middleware/not_found.rb" and add this line below to my application.rb file :

config.middleware.use "NotFound", {:error => "Endpoint Not Found"}.to_json, "application/json"

现在......好吧，它按我的预期工作......它总是返回

and now ... well, it works as I expected ... It always return

{"error"=>"Endpoint Not Found"}

现在我怎样才能让它在路由器出现故障时工作?我看到有一个 insert_after 方法，但在 Application.routes 之后无法实现

Now how can I make it work only if the router fails ? I saw there is a insert_after method but can't make it happen after Application.routes

ps:我知道我可以用 rails3 路由器来处理它，但这是一个实验，我只是玩得开心 :-)

ps : I know I could handle it with the rails3 router, but it's an experiment, I'm just having some fun :-)

谢谢！

推荐答案

当没有路由匹配时，Rails 路由器已经返回 404 响应.如果您想自定义该响应，我想您可以这样做:

The Rails router will already return a 404 response when no routes match. If you want to customize that response, I suppose you could do:

class NotFound
  def initialize(app, msg, content_type = "text/html")
    @app = app
    @content = msg
    @length = msg.size.to_s
    @content_type = content_type
  end

  def call(env)
    status, headers, body = @app.call(env)

    if status == 404
      [404, {'Content-Type' => @content_type, 'Content-Length' => @length}, @content]
    else
      [status, headers, body]
    end
  end
end

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