how can I extract the HTTP POST data when I'm using the http-function?

Hi,
I’m trying to use Twilio programming voice with my site to do the following:

  1. Send HTTP POST from Twilio to one of my “_functions” URL (in http-fuctions.js)
  2. Extract POST data and use it in my post_myFunction
  3. Return the results of myFunction to Twilio
  4. Do something in Twilio

Stages 1,3,4 works just fine.
My Question: in stage 2, how can I extract the POST data? Is there an http-function I can use or some other way?