Question

I’m experiencing something that I can’t explain with Rails 2.3.2. I’ve created a new app, with one controller and one action to try narrowing this down. My entire controller is as follows.

class LinesController < ApplicationController
  def show
    respond_to do |format|
      format.html { render :text => proc {|response, output|
          10.times do |i|
            output.write("This is line #{i}\n")
            output.flush
          end
        }
      }
    end
  end
end

When I run this under Rails 2.2.2 I see the following response.

$ curl http://localhost:3002/lines
This is line 0
This is line 1
This is line 2
This is line 3
This is line 4
This is line 5
This is line 6
This is line 7
This is line 8
This is line 9

However, when I run this under Rails 2.3.2, I get this instead.

$ curl http://localhost:3002/lines
curl: (18) transfer closed with outstanding read data remaining

If I hit this with a browser I see only the first line.

This is line 0

Note that my example code is directly out of the Rails documentation for render, except that I reduced the number of lines from 10 million to 10.

I suspect that the answer lies somewhere in the flush() method, but I’m currently stuck trying to dig an explanation out of the source code.

Answer 1

I believe this bug was resolved on 2-3-stable by commit bc2c4a45959be21e6314fba7876b32c1f04cd08a. Check out the accompanying ticket. You can either wait for 2.3.3 (not that far off now), or freeze the current 2-3-stable from git:

git clone git://github.com/rails/rails.git vendor/rails
cd vendor/rails
git checkout origin/2-3-stable
rm -rf .git