product.js

function(doc, req) {
  // Use ?debug=true to enable debug logging

  if (req.query.debug) log({"Started update handler with argument doc: ": doc})
  if (req.query.debug) log({"Started update handler with argument req: ": req})

  var response = {'ok':true}
  if (req.query.debug) log('Receive Vend webhook: ' + req.body)

  var payload;
  if (req.form && req.form.payload) {
    try        { payload = JSON.parse(req.form.payload) }
    catch (er) { return fail('Bad JSON body for payload: ' + JSON.stringify(req.form.payload)) }
  }

  if (!doc) {
    if (req.query.debug) log('New product received. Payload ID: ' + payload.id)
	  doc = payload
	  doc._id = payload.id
  } else {
    // we never enter this block because the request coming from Vend never sets the "id"
    if (req.query.debug) log('Product update received. Payload ID: ' + payload.id)
    if (req.query.debug) log('Old doc: ' + JSON.stringify(doc))
    // a) get the revision # and id # from the doc that already exists
    payload._rev = doc._rev
    payload._id = doc._id
    // b) might as well update the entire document with the new payload
    //    rather than trying to do a tricky merge
	  doc = payload
	}

  if (req.query.debug) log('Finishing update handler with doc: ' + JSON.stringify(doc))
  return respond(201)

  //
  // Utilities
  //

  function fail(reason) {
    log('Vend ERROR: ' + JSON.stringify(reason))
    doc = null
    return respond(400, {'error':reason})
  }

  function respond(code, body) {
    body = body || response
    body = JSON.stringify(body) + "\n"
    return [doc, {'code':code, 'body':body}]
  }
}