Rails' send_file sends garbage data with jruby

[Hakon]

I am not sure where the source of this problem is, if it's in jruby-rack or rails.
When i send a file from a rails-controller using send_file with a path to the file the client receives only garbage data and way too much of it. This does not happen with MRI. If the file is just plain text the file goes through without problems.

I have set up a test-app here: https://gist.github.com/2770840
Place a compressed file (eg. jpeg or zip) called "testdata.jpeg" in the same directory and run rackup. http://localhost:9292 will now serve you a too large garbage version of that file.

jruby version: jruby 1.6.7 (ruby-1.9.2-p312) (2012-03-21 3e82bc8) (Java HotSpot(TM) Client VM 1.6.0_31) [darwin-i386-java]

[kares]

Hey Hakon, thanks for reporting this - I can definitely confirm it happens !
I can also confirm this only happens with jruby --1.9 the same app on --1.8 runs fine https://gist.github.com/2774140
Someone needs to be messing with File.each as the chunks (line sizes) while running the app seem different

file = File.open('image.jpg', "rb")
file.send(:each) { |line| puts line.size }

than running this piece of code in jruby --1.9 -S irb

[Hakon]

Do you think this is a jruby-issue? Should i report it there?

[kares]

not sure yet, I'll try to explain the behavior here and ask, until then here's a workaround you can use:

require 'action_dispatch/http/response'
ActionDispatch::Response.class_eval do

  def respond_to?(method)
    if method.to_sym == :to_path
      @body.respond_to?(:to_path)
    elsif method.to_sym == :to_channel
      @body.respond_to?(:to_channel)
    else
      super
    end
  end

  def to_channel
    @body.to_channel
  end

end

put it e.g. in an initializer, it also makes your file downloads slicely faster :)

[Hakon]

This doesn't work in development mode since it's using plain rack (?).. The files i'm sending are not that big so i'll just do the send_data file.read routine until this is fixed.

[kares]

@Hakon it's a little weird that the monkey-path did not work for you, could you confirm streaming works with the following version (built with 7b87c78): https://github.com/downloads/kares/jruby-rack/jruby-rack-1.1.7.dev.gem thanks !

[Hakon]

I installed 1.1.7.dev, but it did not fix the problem. I'm not even sure my app loads jruby-rack or the workaround you've made. I did a debug output in an initializer and i'm not seeing any respond_to? to_channel, the only calls are coming from rack-1.4.1.

I have never deployed a jruby application before som i'm a little unsure where jruby-rack fits in to all this, i thought it was just the standard replacement for the rack-gem.

[kares]

ah I see, I should have asked what server you're using after you're previous comment. actually it's possible you're seeing the issue even without jruby-rack since it's really a jruby --1.9 (encoding related) bug. interestingly, it's still a valid issue to be reported here even though you might no even used jruby-rack at all so far :) !

you're probably booting webrick in development mode with jruby, it's a plain ruby server (no "native" code) thus works on both rubies by default. jruby-rack ain't really a replacement but more of a complement to rack that adapts the java servlet api to become "rack-ish". you would need to use a java based server to use jruby-rack under the covers, such as trinidad or deploy your app packaged into a .war with a plain java container such as tomcat ...

lastly, I think the issue ain't going to get fixed with jruby 1.6.x since work seems to go into 1.7 right now which already contains a fix for this (just rvm install jruby-head if you're using rvm - or 1.7.0.preview1 should be fine as well).

also setting Encoding.default_internal = nil after require 'rails' is executed should fix this but than of course you need to be careful as Rails no longer assumes you're strings are UTF-8 based by default.

anyway, thanks again for reporting this - it revealed that our optimized (java channel based) file streaming wasn't being used for rails 3.x anymore ...

[Hakon]

That sounds about right. I'm booting webrick with standard rack. I'm going to deploy this on a java-based webserver later so it's still a valid issue for me.

Thank you for all the help. You identified the problem way quicker than I would have done.
I have just installed 1.7.0.preview1 and I can confirm that it works!

[fpauser]

Same thing here: jruby-1.6.7.2 sends garbage, jruby-1.7.0-preview1 works!

[kares]

released 1.1.7 which handles send_file "image.jpg" with 1.6.7 --1.9 mode as well (on true java servers of course).
I'm not for further mangling on the jruby-rack side, there's a work-around that requires a bit of encoding awareness ...