Skip to content


Subversion checkout URL

You can clone with
Download ZIP
Browse files

updated changelog

  • Loading branch information...
1 parent fa3c4ea commit 0899be5798d20e3e886e5f741d3e4b1bf43afedd @tenderlove tenderlove committed
Showing with 16 additions and 0 deletions.
  1. +16 −0 actionpack/
16 actionpack/
@@ -1,5 +1,21 @@
## Rails 4.0.0 (unreleased) ##
+* Added ActionController::Live. Mix it in to your controller and you can
+ stream data to the client live. For example:
+ class FooController < ActionController::Base
+ include ActionController::Live
+ def index
+ 100.times {
+ # Client will see this as it's written
+ "hello world\n"
+ sleep 1
+ }
+ end
+ end
* Remove ActionDispatch::Head middleware in favor of Rack::Head. *Santiago Pastorino*
* Deprecate `:confirm` in favor of `:data => { :confirm => "Text" }` option for `button_to`, `button_tag`, `image_submit_tag`, `link_to` and `submit_tag` helpers.

17 comments on commit 0899be5


Streaming already exists since 3.1 by passing an object that responds to 'each' to respond_body. Does this duplicate the functionality or does it add something new? Are both methods now supported and if so, when would you use one over the other?


I read that, however I'm not talking about streaming templates. See answer #2 at
Is that not exactly the same thing with different syntax? Am I missing something?


The main difference is that know you can control what is been stream to the user in runtime. In the way that already exists you have to construct the response before send to users


We currently have an app that streams on 3.1 and 3.2 using the 'each' method and we construct the response as we are sending it because the response is too large to fit in memory and it would run into Heroku's 30 second time limit if we didn't start sending data soon enough. Could you give me an example of something you couldn't do with the existing method that you can do with the new one?


I believe the 'each' streaming functionality comes from Rack, so maybe you didn't realize it was there? I can't really see anything that's fundamentally different between the two in terms of functionality. We stream a ~50 GB CSV file using the each method while reading from a DB cursor. Again, maybe I'm missing some new functionality this adds, but I'm not sure what it is.


Again the main difference is that now you can control when and what is being sent to the client. Yes, we know that Rack have streaming functionality but these feature are not the same. Think about AC::Live as a socket.


Aha! Seem I was missing something. Sorry about that.

I did not participate from the discussion to add this feature and I was talking only with my knowledge about the topic.

I'll try to get more information about the topic, and try to answer with a more grounded knowledge if anyone answer first.

Thank you for the discussion and really sorry to make you loose your time explain me.


@adsummos it's about control. Rather than waiting for Rack to pull data from your each method (IOW call your each method), this lets you push data to the response. As @rafaelfranca says, this API is for emulating a socket.


@adsummos The old method will work the same way, feel free to use it.


I'm just trying to understand if this adds something new, and if so, what that is.


@adsummos it adds an IO like API for writing to responses.


so it is just the API? There is no fundamental difference between yield 'response' and 'response' in terms of functionality?


nice, finally streaming api I would use without nightmares :)


Hello, @tenderlove, I use this code in puma
(thin seems not work, just hangs), it crashes
whenever the client closes stream(

rails-project/rails/actionpack/lib/action_dispatch/http/response.rb:75:in write': closed stream (IOError)

So I debug a bit and found out the problem,

module ActionController
module Live
class Buffer < ActionDispatch::Response::Buffer #:nodoc:

  def write(string)
    unless @response.committed?
      @response.headers["Cache-Control"] = "no-cache"
      @response.headers.delete "Content-Length"
    #raise IOError, "closed stream" if closed?
      @buf.push string


the comment out line is what causes the problem, when commented out,
it's ok, so maybe adding this to fix?

Please sign in to comment.
Something went wrong with that request. Please try again.