For several projects, I have had the need to make a Max/Msp patcher communicate over the internet.
The traditional ways of doing this involves net.send or other (See several examples here)
But - This gives trouble if you don't know your IP address. I wanted something, that just works, regardless of where I have plugged the computer in each end in. Random WiFi-hotspot, gallery etc. All places, where it is impossible to open ports in firewalls or get a fixed ip-address.
Google Talk to the rescue
Using a simple chat protocol, XMPP, to make computers talk to each other
- Works behind firewalls
- Low bandwith - No polling
- Easy debugging - Just "listen" in on the chat to see what is going on
- Talk to many nodes simultaneously
XMPP is the protocol that Google Talk and Jabber uses.
The steps involved
Max -> Java : Using mxj objects
Java -> Google Talk : Using the Smack library
Is it fast enough?
- In the free Google App Engine solution, you can transmit up to 20 messages pr. second.
- If you decide to pay a few $ pr day to Google, you can get up to 500 messages pr. second
This is fast enough for me. And, note, we are talking messages, not bytes pr. second!
Troubleshooting
- ? : It worked, but suddenly no messages is coming through
- ! : Don't send to often. Watch you quota on Google App Engine. If you exceed you quota, it takes 24 hours to reset.