http-proxy-server.rb

# This is a trivial HTTP proxy server, intended for use as a troubleshooting tool
# ONLY (not for real, actual, production use). I wrote this because I couldn't find
# a simple HTTP proxy that I could use to test HTTP proxy support in Net::SSH.
#
# This code is in the public domain, so do with it what you will!

require 'socket'

server = TCPServer.new('127.0.0.1', 8080)
client = server.accept

request = client.readline
headers = {}
loop do
  line = client.readline.strip
  break if line.empty?

  key, value = line.split(/:\s*/, 2)
  headers[key.downcase] = value
end

if request =~ /^CONNECT (.*?):(\d+) HTTP/
  host = $1
  port = $2.to_i

  puts "starting proxy to #{host}:#{port}"
  client.write "HTTP/1.0 200 OK\r\n\r\n"

  proxy = TCPSocket.new(host, port)
  loop do
    r, = IO.select([client, proxy])

    if r.include?(client)
      data = client.recv(1024)
      break if data.nil? || data.empty?
      proxy.write(data)
    end

    if r.include?(proxy)
      data = proxy.recv(1024)
      break if data.nil? || data.empty?
      client.write(data)
    end
  end
  proxy.close
else
  puts "not a CONNECT request #{request.inspect}"
end

client.close
server.close