run and patch pd from ruby

pd.rb

require 'socket'
require 'tempfile'

file = Tempfile.new('foo')

# note: using pd netreceive is unsafe, only do this if you know what you're doing
lines =<<-PATCH
#N canvas 87 360 450 300 10;
#X obj 24 25 netreceive 2000 1;
#X obj 24 51 s pd-#{File.basename(file.path)};
#X connect 0 0 1 0;
PATCH

begin
	file.write(lines)
	file.close

	pd_path = case RUBY_PLATFORM
		when /darwin/ then "/Applications/Pd-0.47-1-64bit.app/Contents/Resources/bin/pd" # assumes pd installed on this path
		when /mingw32/ then "pd.exe" # assumes pd.exe is in PATH
		end
	opts = "-nogui -send \"pd dsp 1;\" \"#{file.path}\""
	cmd = pd_path + " " + opts
	pid = case RUBY_PLATFORM
		when /darwin/ then fork { exec(cmd) }
		when /mingw32/ then Process.spawn(cmd)
		end

	puts "wait for pd to start..."
	sleep 1

	freq = 200 + rand(400)
	puts "patch [osc~ #{freq}] =< [dac~]"
	a=UDPSocket.new
	a.connect("127.0.0.1", 2000)
	a.send("obj 10 10 osc~ #{freq};\n", 0)
	a.send("obj 10 10 dac~;\n", 0)
	a.send("connect 2 0 3 0;\n", 0)
	a.send("connect 2 0 3 1;\n", 0)

	puts "wait 5 seconds..."
	sleep 5
ensure
	puts "close pd..."
	Process.kill("KILL", pid)

	file.unlink
end