Rails ActionController::Live - 一次发送所有内容而不是异步

Question

我对 rails ActionController::Live

有疑问

最后我想向用户展示 FFMPEG 的进度，但现在我想得到这个最小的例子运行:

Rails media_controller.rb:

class MediaController < ApplicationController
  include ActionController::Live

  def stream
    puts "stream function loaded"

      response.headers['Content-Type'] = 'text/event-stream'
      i = 0
      begin
        response.stream.write "data: 1\n\n"
        sleep 0.5
        i += 1
        puts "response... data: " + i.to_s
      end while i < 10
    response.stream.close
  end
end

Javascript:

source = new EventSource("/test/0");
source.addEventListener("message", function(response) {
  // Do something with response.data
  console.log('I have received a response from the server: ' + response);
}, false);

当我导航到该站点时，没有显示 JavaScript 错误。一旦我导航到该站点，就会成功调用 MediaController 的 "stream"-Action。我可以通过查看服务器控制台来验证这一点。它给了我以下输出。在每个响应行之后，有 500 毫秒的延迟，如预期的那样：

stream function loaded
response... data: 1
response... data: 2
response... data: 3
response... data: 4
response... data: 5
response... data: 6
response... data: 7
response... data: 8
response... data: 9
response... data: 10
Completed 200 OK in 5005ms (ActiveRecord: 0.8ms)

在JavaScript这边，它给了我以下输出：

(10x) I have received a response from the server: [object MessageEvent]

但问题就在这里，它在5秒后同时从服务器发送了所有这10条消息！然而，预期的行为是，它应该每 0.5 秒向我发送一条消息！

那我做错了什么？哪里出错了？

Answer 1

我可以通过使用不同的网络服务器来解决这个问题。以前我用过 thin 我发现这个 Post on SO:

you can't use AC::Live with Thin

可在此处找到解释：

https://github.com/macournoyer/thin/issues/254#issuecomment-67494889

Thin doesn't work with streaming and ActionController::Live.

The only approach that works with Thin is to use the async API: https://github.com/macournoyer/thin_async. Thin is built exactly for this kind of stuff and making it scale.

Or simpler, use this: https://github.com/SamSaffron/message_bus.

所以切换到另一个服务器解决了问题：

gem 'puma'

从

开始

rails s Puma

Rails ActionController::Live - 一次发送所有内容而不是异步

Rails ActionController::Live - Sends everything at once instead of async

javascript

ruby-on-rails

ffmpeg

server-sent-events

actioncontroller