The WP Ecommerce system itself is a huge pain in the backside to use and work at times as we all know but a nice saving grace is that the plugin has a huge range of hooks and filters which we, as developers, can write plugins and blocks of code to extend.

My latest issue has been the checkout fields system. I am told by one of their staff that it’s due a rewrite in future versions however for those using older versions… You might notice that it’s not the simplest system in the world. Don’t get me wrong it’s my shopping cart of choice but I think there are a few areas where a little work could polish it up nicely. Checkout fields define what questions are asked of the buyer on the checkout page. Default values include their billing and shipping address but it’s not uncommon to want to add fields of our own to that like newsletter signup for instance. A project I am working on at the moment has a pickup point field present which we want to add to the user or admin emails. The ‘shortcodes’ provided are limited but luckily the filter ‘wpsc_transaction_result_message’ (and a couple of others) allows us to hook into it and run our own code as follows:

add_filter('wpsc_transaction_result_message', 'sb_transaction_results_custom_fields');
add_filter('wpsc_transaction_result_report', 'sb_transaction_results_custom_fields');
add_filter('wpsc_transaction_result_message_html', 'sb_transaction_results_custom_fields_html');

function sb_transaction_results_custom_fields_html($message) {
return sb_transaction_results_custom_fields($message, true);
}

function sb_transaction_results_custom_fields($message, $html=false) {
$values = array();

foreach ($_SESSION['wpsc_checkout_saved_values'] as $key=>$value) {
if ($value) {
if (is_array($value)) {
$value = implode(', ', $value);
}

$values[] = $key . ': ' . $value;
}
}

$message = str_replace('%custom_fields%', implode(($html ? '<br />':"\n"), $values), $message);

return $message;
}

These functions will replace the new shortcode %custom_fields% with the entire contents of the checkout form. It’s not pretty in this form which is why we should use the ID and then reference the field name in the database when making it into a plugin. I might do at some point but for now it’s a handy little bit of reference code for people to work with. I am happy to explain more if anyone if interested.