Automatically validates all links and forms on pages generated by MODX Evolution, according to FoxyCart's HMAC Price Validation functionality.

This plugin is easy to install, and should “just work”, so it is recommended for all MODX Evolution installs.

1. Create a directory in your assets/plugins/ directory called foxycart_validation.
2. Download the source file here and put it into the newly created assets/plugins/foxycart_validation/ directory.
3. Edit that file and enter the appropriate $secret and $cart_url values. (The $secret value is your store's API / datafeed key.)
4. Create a plugin named “FoxyCart Validation”.
5. In the “System Events” tab, check the OnWebPagePrerender checkbox.
6. Paste in the code below and save.
7. Go to your FoxyCart admin and enable the price validation under your “advanced” section. Save.
8. Test.
9. Test some more.

• Form “code” values should not have leading or trailing whitespace.
• Cannot use double-pipes in an input's name.
• Empty textareas are assumed to be “open”.

/**
 * FoxyCart Validation Plugin for MODx 1.x (Evolution)
 *
 * @author FoxyCart.com
 * @copyright FoxyCart.com LLC, 2010
 * @version 0.7.0.20100730
 * @license http://www.gnu.org/licenses/lgpl.html GNU Lesser General Public License
 * @example  http://wiki.foxycart.com/docs/cart/validation
 *
 * Requirements:
 *   - Form "code" values should not have leading or trailing whitespace.
 *   - Cannot use double-pipes in an input's name
 *   - Empty textareas are assumed to be "open"
 */
 
$e = &$modx->Event;
 
switch ($e->name) {
	case "OnWebPagePrerender":
		$validate = $modx->config["base_path"].'assets/plugins/foxycart_validation/foxycart.cart_validation.php';
		if (file_exists($validate)) {
			include_once($validate);
			$doc = $modx->documentOutput;
			$modx->documentOutput = FoxyCart_Helper::fc_hash_html($doc);
		}
		break;
 
	default:  // stop here
		return;
		break;
}

Creates a snippet to manually validates links and forms in your pages, according to FoxyCart's HMAC Price Validation functionality.

Snippet Name: FoxyCartGetHMAC

Snippet Code (paste into text box):

<?php
if(!function_exists(get_verification)) {
function get_verification($var_name, $var_value, $var_code) {
$api_key = 'KEY HERE';
$encodingval = htmlspecialchars($var_code) . htmlspecialchars($var_name) . htmlspecialchars($var_value);
return '||'.hash_hmac('sha256', $encodingval, $api_key).($var_value === "--OPEN--" ? "||open" : "");
 
//Use the following to test whether api_key has a value or not (only use in safe, sandbox scenarios!)
//return '$api_key||'.hash_hmac('sha256', $encodingval, $api_key).($var_value === "--OPEN--" ? "||open" : "");
}
}
 
( isset($varName) ) ? $varName : $varName = '';
( isset($varValue) ) ? $varValue : $varValue = '';
( isset($varCode) ) ? $varCode : $varCode = '';
 
if (empty($varName) || empty($varValue) || empty($varCode)) {
return;
}
 
return get_verification($varName, $varValue, $varCode);
?>

[[FoxyCartGetHMAC &varName=`input-name-attrib-tag-here` &varValue=`input-value-attrib-tag-here` &varCode=`sku-code-here` ]]

Example:

<input type="hidden" name="code[[FoxyCartGetHMAC &varName=`code` &varValue=`[*sku*]` &varCode=`[*sku*]`]]" value="[*sku*]"/>

Notice the parts where the variable name code is the same: name=“code and &varName=`code` and where the value is the same: value=”[*sku*]“ and &varValue=`[*sku*]` and where &varCode=`[*sku*]` should be something unique to your product, like the SKU code

Assuming you're using template variables price as [*price*] and sku as [*sku*] and using the pagetitle and SKU for the product name as [*pagetitle*] - [*sku*], and that there's only a single SKU for a single product represented by a resource in the MODX Tree:

<form name="buypanel" class="buypanel" id="buypanel" action="https://SHOPNAME.foxycart.com/cart" method="post" accept-charset="utf-8">
  <input type="hidden" name="code[[FoxyCartGetHMAC &varName=`code` &varValue=`[*sku*]` &varCode=`[*sku*]`]]" value="[*sku*]"/>
  <input type="hidden" name="name" value="[*pagetitle*] - [*sku*][[FoxyCartGetHMAC &varName=`name` &varValue=`[*pagetitle*] - [*sku*]` &varCode=`[*sku*]`]]"/>
  <input type="hidden" name="price[[FoxyCartGetHMAC &varName=`price` &varValue=`[*price*]` &varCode=`[*sku*]`]]" value="[*price*]"/>
  <input type="input" name="quantity[[FoxyCartGetHMAC &varName=`quantity` &varValue=`--OPEN--` &varCode=`[*sku*]`]]" value="1"/>
  <input type="submit" name="submit[[FoxyCartGetHMAC &varName=`submit` &varValue=`--OPEN--` &varCode=`[*sku*]`]]" value="BUY NOW"/>
</form>