[PD] controlling jMax from the Web and from PureData

Mathieu Bouchard matju at sympatico.ca
Thu Feb 13 05:15:23 CET 2003

controlling jMax from the Web and from PureData

I created a new class "ruby_udpsend" that is an emulation of jMax's
"udpsend". Which means you can send messages from PureData to jMax.

I create an objectbox "ruby_udpsend localhost 2042" in PureData. Then I
create an objectbox "udpreceive 2042" in jMax. Then messages i send to
ruby_udpsend will be catched by jMax.

If you have GridFlow 0.6.5 or 0.7.0 installed, you may add this
functionality to PureData by adding those lines to your
~/.gridflow_startup file :


class RubyUDPSend < FObject
  def initialize(host,port)
    @socket = UDPSocket.new
    @host, at port = host.to_s,port.to_i
  def encode(x)
    case x
    when Integer; "\x03" + [x].pack("N")
    when Float; "\x04" + [x].pack("g")
    when Symbol, String; "\x01" + x.to_s + "\x02"
  def method_missing(sel,*args)
    sel=sel.to_s.sub /^_\d_/, ""
    @socket.send encode(sel) +
      args.map{|arg| encode(arg) }.join("") + "\x0b",
      0, @host, @port
  install "ruby_udpsend", 1, 0


Furthermore, the above code can be combined with the following one to
produce a CGI script capable of sending messages to jMax...



STDERR.reopen "/dev/null", "w"
require "cgi"
require "gridflow"
include GridFlow  

puts "Content-type: text/plain", "", "hello world!"
message = CGI.new.params['message'][0]

# create the gridflow object
s = RubyUDPSend.new "karelia", 2042

# convert values and send in inlet 0 of the gridflow object
s.send_in 0, *(message.split(',').map {|atom|
  if atom =~ /^\d/ then
    if atom =~ /\.|E/i then Float(atom) else Integer(atom) end


Mathieu Bouchard                       http://artengine.ca/matju

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