Customizing the image to be posted to Pinterest

Problem/Motivation

The Pinterest widget allows images to be posted to pinterest.com. However, the image url needs to change on every page, and the AddThis module doesn't allow this functionality.

According to http://www.addthis.com/features/pinterest the anchor tag needs the following attribute added:

pi:init:media="http://YOUR-DOMAIN.com/IMAGE.jpg"

The full output should then be:

<a class="addthis_button_pinterest_pinit" pi:pinit:media="http://YOUR-DOMAIN.com/IMAGE.jpg" pi:pinit:layout="horizontal"></a>

This is achievable by using the "Customize Services" at admin/settings/addthis/custom (see screenshot).

However, that hard-codes the image url, and we need it dynamically generated per page.

Proposed resolution

The Service Customizations are retrieved like so:

$definitions = variable_get('addthis_service_customizations', array());

I propose adding the following after that line:

drupal_alter('addthis_service_customizations_alter', $definitions);

Then either the AddThis module can add some code to implement this hook, or break this off into another module - which may be preferable, since we need to choose which image to pin per node (the easy solution: a CCK image field; the hard solution: grab the first image that shows up in the node body).