Ruby Net::HTTP Expect-100 continue PUT bug

client.rb

require 'net/http'
require 'logger'

req = Net::HTTP::Put.new('/', { 'expect' => '100-continue' })
req.body = 'data'

http = Net::HTTP.new('localhost', 3000)
http.continue_timeout = 1
http.set_debug_output(Logger.new($stdout))
http.request(req)

instructions.txt

# Start the sample server. This server alternates between responding with 100-continue and
# resopnding with a 403 Forbidden. The client **should** be able to handle both responses.

$ ruby server.rb

# In another terminal window, run the client code twice. The first invocation will succeed.
# The second invocation will fail the client with an error.

$ ruby client.rb
$ ruby client.rb

server.rb

# This example server accepts a simple PUT request with the 'Excpect: 100-continue'
# header. It alternates between the following two responses:
#
# * 100 Continue, accepting the body, then 200 OK
# * 403 Forbidden, not accepting the body
#

require 'socket'

server = TCPServer.new('localhost', 3000)

n = 0
loop do

  socket = server.accept

  req_method, req_uri, http_version = socket.gets.split(/\s+/)
  req_headers = {}
  line = socket.gets
  until line == "\r\n"
    key, value = line.split(/:\s*/, 2)
    req_headers[key.downcase] = value
    line = socket.gets
  end

  content_length = req_headers['content-length'].to_i

  if n % 2 == 0
    socket.print("HTTP/1.1 100 Continue\r\n")
    socket.print("\r\n")
    socket.read(content_length)
    socket.print("HTTP/1.1 200 OK\r\n")
    socket.print("\r\n")
  else
    socket.print("HTTP/1.1 403 Forbidden\r\n")
    socket.print("\r\n")
  end

  n += 1
  socket.close

end