I've setup unicorn in rails 3.1 and http streaming works until I enable Rack::Deflater. I've tried both with and without use Rack::Chunked. In curl I can see my response while in chrome I get the following errror: ERR_INVALID_CHUNKED_ENCODING
The result is same in other browsers (firefox, safari) and between development (osx) and production (heroku).
config.ru:
require ::File.expand_path('../config/environment', __FILE__)
use Rack::Chunked
use Rack::Deflater
run Site::Application
unicorn.rb:
listen 3001, :tcp_nopush => false
worker_processes 1 # amount of unicorn workers to spin up
timeout 30 # restarts workers that hang for 30 seconds
controller:
render "someview", :stream => true
Thanks for any help.
The problem is that Rails ActionController::Streaming renders directly into a Chunked::Body. This means the content is first chunked and then gzipped by the Rack::Deflater middleware, instead of gzipped and then chunked.
According to the HTTP/1.1 RFC 6.2.1, chunked must be last applied encoding to a transfer.
Since "chunked" is the only transfer-coding required to be understood by HTTP/1.1 recipients, it plays a crucial role in delimiting messages on a persistent connection. Whenever a transfer-coding is applied to a payload body in a request, the final transfer-coding applied must be "chunked".
I fixed it for us by monkey patching ActionController::Streaming _process_options and _render_template methods in an initializer so it does not wrap the body in a Chunked::Body, and lets the Rack::Chunked middleware do it instead.
module GzipStreaming
def _process_options(options)
stream = options[:stream]
# delete the option to stop original implementation
options.delete(:stream)
super
if stream && env["HTTP_VERSION"] != "HTTP/1.0"
# Same as org implmenation except don't set the transfer-encoding header
# The Rack::Chunked middleware will handle it
headers["Cache-Control"] ||= "no-cache"
headers.delete('Content-Length')
options[:stream] = stream
end
end
def _render_template(options)
if options.delete(:stream)
# Just render, don't wrap in a Chunked::Body, let
# Rack::Chunked middleware handle it
view_renderer.render_body(view_context, options)
else
super
end
end
end
module ActionController
class Base
include GzipStreaming
end
end
And leave your config.ru as
require ::File.expand_path('../config/environment', __FILE__)
use Rack::Chunked
use Rack::Deflater
run Roam7::Application
Not a very nice solution, it will probably break some other middlewares that inspect/modify the body. If someone has a better solution I'd love to hear it.
If you are using new relic, its middleware must also be disabled when streaming.
来源:https://stackoverflow.com/questions/7986150/http-streaming-in-rails-not-working-when-using-rackdeflater