Streaming with webrick

ruby-talk
1

Can someone explain to me why the following serverlet doesn't stream
Hellos.

require 'webrick'

class Streamlet < WEBrick::HTTPServlet::AbstractServlet
  def do_GET(req, res)
    res["content-type"] = "text/plain"
    r, w = IO.pipe
    res.body = r
    res.chunked = true

    Thread.new do
      5.times do |i|
        w.write("hello #{i}\n")
        sleep(1)
      end
      w.close
    end
  end
end

@server = WEBrick::HTTPServer.new(:Port => 4711)
@server.mount("/stream", Streamlet)

trap("INT") { @server.shutdown }
@server.start

Thank you.

2

Can someone explain to me why the following serverlet doesn't stream
Hellos.

require 'webrick'

class Streamlet < WEBrick::HTTPServlet::AbstractServlet
  def do_GET(req, res)
    res["content-type"] = "text/plain"
    r, w = IO.pipe
    res.body = r
    res.chunked = true

    Thread.new do
      5.times do |i|

I believe that 5 isn't enough hellos to fill up a chunk. Changing this to loop do ... end causes webrick to give you infinite hellos.

···

On Mar 31, 2007, at 18:20, Ry wrote:

        w.write("hello #{i}\n")
        sleep(1)
      end
      w.close
    end
  end
end

@server = WEBrick::HTTPServer.new(:Port => 4711)
@server.mount("/stream", Streamlet)

trap("INT") { @server.shutdown }
@server.start

Thank you.

3

I believe that 5 isn't enough hellos to fill up a chunk. Changing
this to loop do ... end causes webrick to give you infinite hellos.

Looking at the webrick's code in httpresponse.rb

261 while buf = @body.read(BUFSIZE)
262 next if buf.empty?
263 data = ""
264 data << format("%x", buf.size) << CRLF
265 data << buf << CRLF

The servlet reaches line 261 immediately but hangs for 5 seconds
before getting to line 262. If the IO.pipe only has a bit of data in
it, it seems like @body.read(BUFSIZE) should only return what is in
there and not wait for BUFSIZE.

Is there a way to avoid this behavior?

Thanks,
ry