CouchDB: POST Data in Update Handler

[Hank Knight <hk...@gmail.com>]

I can access query data and apply it in an update handler like this:
function(doc, req) {
 doc.xyz = req.query.xyz;
 return [doc, 'Updated'];
}

This allows me to update the value of xyz like this:
?xyz=123

Is there any way to access data sent via POST?