Access data when posting to controller from front-end

Question

I'm writing a plugin to notify authors when a Disqus comment is posted. There is a Disqus JS callback you can use to hook into this, so I'm doing the following on the front-end:

this.callbacks.onNewComment = [function(comment) {
  var commentNotification = new window.VIGET.CommentNotification();

  commentNotification.notify('{{ actionUrl("vigetDisqus/notify/notify") }}', comment, {{ entry.id }}, {{ entry.author.id }});
}];

So I am passing the actionUrl of my controller, the comment itself, the entry id, and the author id. This all works perfectly fine, and I am passing it as data along as an AJAX request to the controller.

CommentNotification.prototype = {
  notify: function(actionUrl, comment, entryId, authorId) {
    var data = JSON.stringify({
      comment: comment,
      entryId: entryId,
      authorId: authorId
    });

    xhr({
      uri: actionUrl,
      method: 'POST',
      body: data,
      headers: {
        'Content-Type': 'application/json',
        'X-Requested-With': 'XMLHttpRequest'
      }
    }, function(err, resp) {
      console.log(resp.body)
    });
  }
};

How do I access the posted data inside my controller? I thought I could use the getPost method, but I am always getting null.

<?php
namespace Craft;

class VigetDisqus_NotifyController extends BaseController
{
    protected $allowAnonymous = true;

    public function actionNotify()
    {
        $this->requirePostRequest();
        $this->requireAjaxRequest();

        $authorId = craft()->request->getPost('authorId');

        $this->returnJson(array('authorId' => $authorId));
    }
}

Answer 1

Turns out the ajax library I was using was expecting the data to be passed in a serialized format:

'comment=' + comment + '&entryId=' + entryId + '&authorId=' + authorId

With that as the body of the request, the data became accessible to my controlled by using craft()->request->getPost