ruby - 使用 Thin 或根本不进行流式传输的缓慢流式传输

Question

我写了一个小脚本来使用 Sinatra 和 Thin 按字节流式传输文件:

#!/usr/bin/env ruby

require 'sinatra'
require "sinatra/streaming"

get '/' do
  stream do |out|
    File.open("/usr/share/doc/ia32-libs/copyright", "r") do |fd|
      fd.each_byte do |byte|
        break if out.closed?
        putc byte.chr
        out << byte.chr unless out.closed?
      end
    end
  end
end

这按预期工作:

% ruby streamer.rb
== Sinatra/1.3.2 has taken the stage on 4567 for development with backup from Thin
>> Thin web server (v1.4.1 codename Chromeo)
>> Maximum connections set to 1024
>> Listening on 0.0.0.0:4567, CTRL+C to stop


% curl http://127.0.0.1:4567

文件内容在两边都写到stdout

如果我删除 putc byte.chr 行，服务器就会崩溃并被 kill -9 杀死

---

如果我将此脚本更改为模块化样式并添加 config.ru，则会出现另一个意外行为:

#!/usr/bin/env ruby

require 'sinatra/base'
require "sinatra/streaming"

class TestStreamer < Sinatra::Base
  helpers Sinatra::Streaming

  get '/' do
    stream do |out|
      File.open("/usr/share/doc/ia32-libs/copyright", "r") do |fd|
        fd.each_byte do |byte|
          break if out.closed?
#          putc byte.chr
          out << byte.chr unless out.closed?
        end
      end
    end
  end
end

配置.ru:

$:.unshift(File.join(File.dirname(__FILE__)))

require 'rubygems'
require 'sinatra/base'
require 'streamer_modular'

map '/' do
  run TestStreamer
end

它启动了:

% thin start
>> Using rack adapter
>> Thin web server (v1.4.1 codename Chromeo)
>> Maximum connections set to 1024
>> Listening on 0.0.0.0:3000, CTRL+C to stop

但是当我发出请求时，文件在两边发送的速度都非常慢，并在 30 秒左右后关闭。在这种情况下，Sinatra 不会崩溃。

% time curl -v http://127.0.0.1:3000
* About to connect() to 127.0.0.1 port 3000 (#0)
*   Trying 127.0.0.1... connected
* Connected to 127.0.0.1 (127.0.0.1) port 3000 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.21.0 (x86_64-pc-linux-gnu) libcurl/7.21.0 OpenSSL/0.9.8o zlib/1.2.3.4 libidn/1.15 libssh2/1.2.6
> Host: 127.0.0.1:3000
> Accept: */*
> 
< HTTP/1.1 200 OK
< X-Frame-Options: sameorigin
< X-XSS-Protection: 1; mode=block
< Content-Type: text/html;charset=utf-8
< Connection: close
< Server: thin 1.4.1 codename Chromeo
< 
* Closing connection #0
This package was cre
curl -v http://127.0.0.1:3000  0,01s user 0,00s system 0% cpu 32,559 total

当我删除 stream-helper 时，文件会立即写入服务器端的标准输出:

#!/usr/bin/env ruby

require 'sinatra/base'
require "sinatra/streaming"

class TestStreamer < Sinatra::Base
  helpers Sinatra::Streaming

  get '/' do
#    stream do |out|
    begin
      File.open("/usr/share/doc/ia32-libs/copyright", "r") do |fd|
        fd.each_byte do |byte|
        #  break if out.closed?
          putc byte.chr
        #  out << byte.chr unless out.closed?
        end
      end
    end
  end
end

---

% ruby -v
ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-linux]

% gem list

*** LOCAL GEMS ***

backports (2.6.2)
bundler (1.1.5, 1.1.3)
daemons (1.1.8)
eventmachine (0.12.10)
rack (1.4.1)
rack-protection (1.2.0)
rack-test (0.6.1)
sinatra (1.3.2)
sinatra-contrib (1.3.1)
thin (1.4.1)
tilt (1.3.3)

% gem update
Updating installed gems
Nothing to update

% ls -al /usr/share/doc/ia32-libs/copyright
-rw-r--r-- 1 root root 607403  2. Jan 2012  /usr/share/doc/ia32-libs/copyright

% head -n2 /usr/share/doc/ia32-libs/copyright
This package was created by Daniel Jacobowitz <dan@debian.org> on Sun, Aug
8th, 2004.  It was based on the ia32-libs package by Bdale Garbee

我错过了什么吗？你能重现这个吗？也许能为我找到解决方法？

Answer 1

在这种模式下，在 Thin 上逐字节流式传输效率有点低，因为 Thin 是基于 EventMachine 的，因此需要大量的调度和延迟(因此 Mike 评论流式传输不适用于 Thin，Mike 可能有 Rails 背景Thin 上的此类流式传输确实不起作用)。

但是，Thin(和任何 Rack 服务器)应该能够直接流式传输文件:

get '/' do
  File.open("/usr/share/doc/ia32-libs/copyright", "r")
end