rails4使用长连接

开发瑞信通的时候偶然看到了ActionController::Live，可以做类似即时通讯的东西，不过不支持webrick，只支持puma和unicorn~，具体使用如下：

class MyController < ActionController::Base
 # 步骤 1
 include ActionController::Live
 def stream
 # 步骤 2
 response.headers['Content-Type'] = 'text/event-stream'
 100.times {
 # 步骤 3 直接使用 response.stream
 response.stream.write "hello world\n"
 sleep 1
 }
 ensure
 # 步骤 4
 response.stream.close
 end
 end
 

可以直接在页面直接访问 /my/stream即可
不过更合适通过ajax去访问，因为HTML5有一个服务器推送事件(Server-sent Events)
http://www.ibm.com/developerworks/cn/web/1307_chengfu_serversentevent/
通过ajax访问如下：

 jQuery(document).ready(function(){
 var source = new EventSource("/my/stream");
 source.addEventListener('update', function(e){
 $("#target_div").append(e)
 // update a div, reload a section of the page
 });
 // you can add different event listeners to
 // process some logic based on the event push
 // from the server to do something unique based
 // users leaving, joining the application or other
 // kinds of events not releated to users.
 });
 

下面有个ActionController::Live +redis+resque的简单实时聊天实现，有兴趣的同学可以去看看
http://stackoverflow.com/questions/29150274/how-to-use-actioncontrollerlive-along-with-resque-redis-for-chat-applicatio