使用Rack :: Deflater时Rails中的HTTP流无法正常工作 [英] HTTP streaming in rails not working when using Rack::Deflater

问题描述

我已经在rails 3.1中设置了独角兽，并且在启用Rack :: Deflater之前，http流媒体可以正常工作. 我已经尝试过使用和不使用Rack :: Chunked.在curl中，我可以看到我的响应，而在chrome中，我会看到以下错误:ERR_INVALID_CHUNKED_ENCODING

I've setup unicorn in rails 3.1 and http streaming works until I enable Rack::Deflater. I've tried both with and without use Rack::Chunked. In curl I can see my response while in chrome I get the following errror: ERR_INVALID_CHUNKED_ENCODING

在其他浏览器(firefox，safari)以及开发(osx)和生产版(heroku)之间，结果是相同的.

The result is same in other browsers (firefox, safari) and between development (osx) and production (heroku).

config.ru:

config.ru:

require ::File.expand_path('../config/environment',  __FILE__)
use Rack::Chunked
use Rack::Deflater
run Site::Application

unicorn.rb:

unicorn.rb:

listen 3001, :tcp_nopush => false
worker_processes 1 # amount of unicorn workers to spin up
timeout 30         # restarts workers that hang for 30 seconds

控制器:

render "someview", :stream => true

感谢您的帮助.

推荐答案

问题是Rails ActionController :: Streaming直接将其渲染到Chunked :: Body中.这意味着首先将内容分块，然后由Rack :: Deflater中间件压缩，而不是先压缩然后分块.

The problem is that Rails ActionController::Streaming renders directly into a Chunked::Body. This means the content is first chunked and then gzipped by the Rack::Deflater middleware, instead of gzipped and then chunked.

根据 HTTP/1.1 RFC 6.2.1 ，分块必须最后应用于传输编码.

According to the HTTP/1.1 RFC 6.2.1, chunked must be last applied encoding to a transfer.

由于分块"是唯一需要理解的传输编码 通过HTTP/1.1收件人，它在定界消息中起着至关重要的作用 在持久的连接上.只要将传输编码应用于 请求中的有效负载主体，应用的最终传输编码必须为 分块".

Since "chunked" is the only transfer-coding required to be understood by HTTP/1.1 recipients, it plays a crucial role in delimiting messages on a persistent connection. Whenever a transfer-coding is applied to a payload body in a request, the final transfer-coding applied must be "chunked".

我通过猴子在初始化器中修补ActionController :: Streaming _process_options和_render_template方法为我们修复了此问题，因此它不会将主体包装在Chunked :: Body中，而由Rack :: Chunked中间件来代替.

I fixed it for us by monkey patching ActionController::Streaming _process_options and _render_template methods in an initializer so it does not wrap the body in a Chunked::Body, and lets the Rack::Chunked middleware do it instead.

module GzipStreaming
  def _process_options(options)
    stream = options[:stream]
    # delete the option to stop original implementation  
    options.delete(:stream)
    super
    if stream && env["HTTP_VERSION"] != "HTTP/1.0"
      # Same as org implmenation except don't set the transfer-encoding header
      # The Rack::Chunked middleware will handle it 
      headers["Cache-Control"] ||= "no-cache"
      headers.delete('Content-Length')
      options[:stream] = stream
    end
  end

  def _render_template(options)
    if options.delete(:stream)
      # Just render, don't wrap in a Chunked::Body, let
      # Rack::Chunked middleware handle it
      view_renderer.render_body(view_context, options)
    else
      super
    end
  end
end

module ActionController
  class Base
    include GzipStreaming
  end
end

然后将您的config.ru保留为

And leave your config.ru as

require ::File.expand_path('../config/environment',  __FILE__)
use Rack::Chunked
use Rack::Deflater
run Roam7::Application

这不是一个很好的解决方案，它可能会破坏其他一些检查/修改主体的中间件.如果有人有更好的解决方案，我很想听听.

Not a very nice solution, it will probably break some other middlewares that inspect/modify the body. If someone has a better solution I'd love to hear it.

如果您使用的是新遗物，则其中间件也必须为

If you are using new relic, its middleware must also be disabled when streaming.

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