socket_fun.rb

# Below, "telnet curl" means curl telnet://localhost:8080/
# "http curl" means curl http://localhost:8080/
# telnet curl is sometimes used here because it approximates a raw tcp mode for
# curl. On OS X telnet curl waits for more input on the client side, not sure
# why. Linux telnet curl exits immediately, which is desirable for these tests.

require 'socket'

file_counter = 0

Socket.tcp_server_loop(8080) do |sock, client_addrinfo|

  file_counter += 1

  # Oddly, even if you only specify the first line of the the HTTP response
  # header you can still make curl happy by making the server concurrent.
  Thread.new(file_counter) do |file_counter|
    begin

      filepath = "/tmp/#{file_counter}"

      # touch the file to make this thread respond to the request.
      loop do
        puts "Looking for #{filepath}"
        break if File.exist? filepath
        sleep 1
      end

      content = "#{file_counter}\n"

      # Only telnet curl (see above) is okay with this.
      #sock.write "#{content}"

      # If this is all you send then Firefox and http curl will sometimes be
      # happy, sometimes not. Chrome never accepts this. http curl is also
      # always happy if the server is concurrent (see above).
      #sock.write "HTTP/1.1 200 OK\n\n#{content}"

      # Only the first byte of content will be rendered, even if the actual
      # content sent is longer.
      #sock.write "HTTP/1.1 200 OK\nContent-Length: 1\n\n#{content}"

      # Everybody's happy!
      sock.write "HTTP/1.1 200 OK\nContent-Length: #{content.size}\n\n#{content}"

      # If Content-Length is longer than the content, everybody throws an error
      # because they expected more content before the connection is closed.
      #sock.write "HTTP/1.1 200 OK\nContent-Length: #{content.size + 1}\n\n#{content}"
    ensure
      sock.close
    end
  end
end