Streaming with webrick

Ruby
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

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

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.

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