Rails ActionController :: Live-一次发送所有内容，而不是异步 [英] Rails ActionController::Live - Sends everything at once instead of async

问题描述

我在rails ActionController :: Live

最后，我想向用户展示FFMPEG的进度，但是现在，我想让这个最小的示例运行:

In the end I want to show the progress of FFMPEG to the user, but for now I want to get this minimal example running:

打开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.一旦导航到该站点，就成功调用了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.每条响应线之后都有500毫秒的延迟，如预期的那样:

When I navigate to the site, there are no JavaScript Errors showing. As soon as I navigate to the site, the "stream"-Action of the MediaController gets successfully called. I can verify this, by looking at the Server-Console. It gives me the following output. After every response line, there is a 500ms delay, like expected:

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方面，它提供了以下输出:

On the JavaScript Side, it gives me the following Output:

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

但是问题出在这里，它会在同时 5秒钟后从服务器发送所有这10条消息！但是，预期的行为是它应该每0.5秒向我发送1条消息！

But the problem is here, that it sends all these 10 Messages from the server after 5 seconds at the same time! The expected behavior however is, that it should send me 1 message every 0.5 seconds!

那么我在这里做错了什么?错误在哪里?

So what am I doing wrong here? Where is the error?

推荐答案

我可以通过使用其他Web服务器来解决此问题.以前，我使用的是 thin ，我发现了这个发布在SO上:

I could resolve the issue, by using a different Webserver. Previously I used thin and I found this Post on SO:

您不能将 AC :: Live 与 Thin

可以在此处找到说明

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

Thin不适用于流媒体和ActionController :: Live.

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

与Thin配合使用的唯一方法是使用异步API: https://github.com/macournoyer/thin_async .Thin正是为这种东西而构建的，并使其可扩展.

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.

或更简单的方法是，使用: https://github.com/SamSaffron/message_bus ./p>

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

因此切换到另一台服务器解决了该问题:

So switching to another Server solved the issue:

gem 'puma'

以

rails s Puma

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