My Experiment with "Messaging"

Sat, Mar 24, 2001; by Dave Winer.

What is messaging? 

That's a good question. We'll figure it out.

This is just an experiment, not a spec, just something to try out and discuss if there's interest.

A metaphor 

In StarTrek: The Next Generation, the Enterprise got a new feature, they could separate the ship into two parts. This experiment is like that. XML-RPC is and always will be a creature of HTTP. But what about the payload format, could it be transported through other protocols? Of course it can. So today I boldly went where no one has gone before and started doing RPC across SMTP.

Check it out 

Earlier, I cc'd the XML-RPC mail list on a conversation between test1@userland.com and test2@userland.com, two mailboxes.

Here's the request and the response.

Basically you send an email to test1@userland.com and if its body is a properly formatted XML-RPC <methodCall> it calls the procedure on my server, and returns the result in an email message.

All the basic "example" scripts are available, and you're free to give it a try for the next few days, and maybe longer if it catches on.

Matching up responses with calls 

When responding my agent will return with the same subject you specified on your request, tacking a "Re:" in front as is the convention in human-edited email. You can pop the Re: part off, and index into a table of completion routines, as I have done in my test scripts. You almost certainly want to have the ability to run code on a return.

You can cc messages 

If you have a cc on the email, my agent will send the reply to the cc list as well. This is useful for debugging and showing off.