Product events (catalog)
Modifying product price, weight and fields on catalog output.
Feature
These events support a plugin chain — each plugin can read the previous result from $modx->eventData and pass its own result to the next one.
msOnGetProductPrice
Fired when getting product price. Lets you modify the price on the fly.
Parameters
| Parameter | Type | Description |
|---|---|---|
data | array | Product data. By default this is toArray() of the msProductData object (core fields: price, article, weight, stock, vendor_id, tags, color, size, and others), or an extended row when the caller passed its own $data (for example ms3_products.php passes the whole listing row, including its own fields) |
price | float | Current price |
Modifying data (with chain support)
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductPrice':
// The price may already have been changed by another plugin
$price = $modx->eventData['msOnGetProductPrice']['price']
?? $scriptProperties['price'];
$data = $scriptProperties['data'];
// 15% off for category 5
if ($data['parent'] == 5) {
$price = $price * 0.85;
}
// Hand it on to the plugins that run after this one
$modx->eventData['msOnGetProductPrice']['price'] = $price;
// Return the result
$values = &$modx->event->returnedValues;
$values['price'] = $price;
break;
}Personal prices
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductPrice':
$price = $modx->eventData['msOnGetProductPrice']['price']
?? $scriptProperties['price'];
$data = $scriptProperties['data'];
// VIP discount
if ($modx->user->isMember('VIP')) {
$price = $price * 0.8; // -20%
}
// Wholesale price when the extra field wholesale_price exists
if ($modx->user->isMember('Wholesale')) {
$wholesalePrice = $data['wholesale_price'] ?? 0;
if ($wholesalePrice > 0) {
$price = $wholesalePrice;
}
}
$modx->eventData['msOnGetProductPrice']['price'] = $price;
$values = &$modx->event->returnedValues;
$values['price'] = $price;
break;
}Dynamic markup by currency rate
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductPrice':
$price = $modx->eventData['msOnGetProductPrice']['price']
?? $scriptProperties['price'];
// Rate out of the cache, or from an API
$rate = $modx->cacheManager->get('usd_rate') ?? 90;
// Convert a product priced in dollars when the extra field currency exists
$data = $scriptProperties['data'];
if (($data['currency'] ?? null) === 'USD') {
$price = $price * $rate;
}
$modx->eventData['msOnGetProductPrice']['price'] = $price;
$values = &$modx->event->returnedValues;
$values['price'] = round($price, 2);
break;
}msOnGetProductWeight
Fired when getting product weight. Lets you modify weight on the fly.
Parameters
| Parameter | Type | Description |
|---|---|---|
data | array | Product data. By default toArray() of the msProductData object, or an extended row when the caller passed its own $data |
weight | float | Current weight |
Modifying data
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductWeight':
$weight = $modx->eventData['msOnGetProductWeight']['weight']
?? $scriptProperties['weight'];
$data = $scriptProperties['data'];
// Add the packaging weight (500 g)
$packagingWeight = 0.5;
$weight = $weight + $packagingWeight;
$modx->eventData['msOnGetProductWeight']['weight'] = $weight;
$values = &$modx->event->returnedValues;
$values['weight'] = $weight;
break;
}Volumetric weight
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductWeight':
$weight = $modx->eventData['msOnGetProductWeight']['weight']
?? $scriptProperties['weight'];
$data = $scriptProperties['data'];
// Dimensions when the extra fields length, width and height exist
$length = $data['length'] ?? 0;
$width = $data['width'] ?? 0;
$height = $data['height'] ?? 0;
// Volumetric weight: the 5000 divisor is the courier standard
if ($length > 0 && $width > 0 && $height > 0) {
$volumeWeight = ($length * $width * $height) / 5000;
// Whichever weight is larger wins
$weight = max($weight, $volumeWeight);
}
$modx->eventData['msOnGetProductWeight']['weight'] = $weight;
$values = &$modx->event->returnedValues;
$values['weight'] = $weight;
break;
}msOnGetProductFields
Fired when getting product fields. Lets you add or modify any fields.
Added fields never reach the public Web API
Right after the event, ProductCatalogService runs the result through whitelistPublicPayload() and keeps only the keys of two static lists — RESOURCE_FIELDS and DATA_FIELDS (twelve names: article, price, old_price, stock, weight, image, thumb, vendor_id, made_in, new, popular, favorite).
So everything a plugin adds to data is visible in Fenom snippets and chunks, but is stripped from the GET /api/v1/products and GET /api/v1/products/{id} responses. On a server-rendered site the example works; on a headless storefront it silently does not.
The allowlist is static: columns created by the Extra fields utility do not pass either. To expose a field of your own you need your own endpoint or catalogue controller.
Parameters
| Parameter | Type | Description |
|---|---|---|
data | array | Product data. By default toArray() of the msProductData object, or an extended row when the caller passed its own $data |
Modifying data
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductFields':
$data = $modx->eventData['msOnGetProductFields']['data']
?? $scriptProperties['data'];
// Add the computed fields
$data['discount_percent'] = 0;
if ($data['old_price'] > 0 && $data['price'] > 0) {
$data['discount_percent'] = round(
(($data['old_price'] - $data['price']) / $data['old_price']) * 100
);
}
// Add the availability status
$stock = $data['stock'] ?? 0;
if ($stock <= 0) {
$data['availability'] = 'out_of_stock';
$data['availability_text'] = 'Out of stock';
} elseif ($stock < 5) {
$data['availability'] = 'low_stock';
$data['availability_text'] = 'Low stock';
} else {
$data['availability'] = 'in_stock';
$data['availability_text'] = 'In stock';
}
$modx->eventData['msOnGetProductFields']['data'] = $data;
$values = &$modx->event->returnedValues;
$values['data'] = $data;
break;
}Adding related data
The review model in the example is yours
MiniShop3 has no msProductReview class: in the example it stands for your own review model, or any other source of related data. Substitute the real class of your extra.
php
<?php
switch ($modx->event->name) {
case 'msOnGetProductFields':
$data = $modx->eventData['msOnGetProductFields']['data']
?? $scriptProperties['data'];
// Add the review count
$reviewCount = $modx->getCount('msProductReview', [
'product_id' => $data['id'],
'published' => 1,
]);
$data['review_count'] = $reviewCount;
// Add the average rating
$c = $modx->newQuery('msProductReview');
$c->where(['product_id' => $data['id'], 'published' => 1]);
$c->select('AVG(rating) as avg_rating');
if ($c->prepare() && $c->stmt->execute()) {
$data['avg_rating'] = round($c->stmt->fetchColumn(), 1);
}
$modx->eventData['msOnGetProductFields']['data'] = $data;
$values = &$modx->event->returnedValues;
$values['data'] = $data;
break;
}Full example: discounts and promotions
php
<?php
/**
* Plugin: Discounts and promotions
* Events: msOnGetProductPrice, msOnGetProductFields
*/
switch ($modx->event->name) {
case 'msOnGetProductPrice':
$price = $modx->eventData['msOnGetProductPrice']['price']
?? $scriptProperties['price'];
$data = $scriptProperties['data'];
$discounts = [];
// 1. Discount by category
$categoryDiscounts = [
5 => 10, // Category 5 — 10% off
10 => 15, // Category 10 — 15% off
];
if (isset($categoryDiscounts[$data['parent']])) {
$discount = $categoryDiscounts[$data['parent']];
$price = $price * (1 - $discount / 100);
$discounts['category'] = $discount;
}
// 2. Discount for signed-in customers
if ($modx->user->isAuthenticated()) {
$price = $price * 0.95; // -5%
$discounts['member'] = 5;
}
// 3. VIP discount
if ($modx->user->isMember('VIP')) {
$price = $price * 0.9; // -10%
$discounts['vip'] = 10;
}
// Keep the discount breakdown for msOnGetProductFields
$modx->eventData['discounts'] = $discounts;
$modx->eventData['msOnGetProductPrice']['price'] = $price;
$values = &$modx->event->returnedValues;
$values['price'] = round($price, 2);
break;
case 'msOnGetProductFields':
$data = $modx->eventData['msOnGetProductFields']['data']
?? $scriptProperties['data'];
// Add the discount breakdown
$discounts = $modx->eventData['discounts'] ?? [];
if (!empty($discounts)) {
$data['applied_discounts'] = $discounts;
$data['total_discount'] = array_sum($discounts);
}
// Add the badges
$badges = [];
if ($data['new']) {
$badges[] = ['type' => 'new', 'text' => 'New'];
}
if ($data['popular']) {
$badges[] = ['type' => 'popular', 'text' => 'Bestseller'];
}
if (!empty($data['total_discount'])) {
$badges[] = [
'type' => 'sale',
'text' => '-' . $data['total_discount'] . '%',
];
}
$data['badges'] = $badges;
$modx->eventData['msOnGetProductFields']['data'] = $data;
$values = &$modx->event->returnedValues;
$values['data'] = $data;
break;
}msOnGetPublicSeo
Fired in PublicSeoService after the SEO set and the TV overlay map (ms3_public_seo_tv_map) are assembled, just before the final whitelist. Works for both products and categories. On list and tree requests include_seo=0 by default; on get it is 1.
Parameters
| Parameter | Type | Description |
|---|---|---|
seo | array | The current SEO whitelist |
payload | array | The catalog row (product or category) |
og_type | string | product, or website for a category |
Modifying
A plugin returns a patch in $modx->event->returnedValues['seo']. Unknown keys are dropped by the whitelist. og.title / og.description copy title / description unless the patch sets them explicitly in seo.og.
php
<?php
switch ($modx->event->name) {
case 'msOnGetPublicSeo':
$seo = $scriptProperties['seo'];
$payload = $scriptProperties['payload'];
$ogType = $scriptProperties['og_type'];
if ($ogType === 'product' && !empty($payload['vendor'])) {
$seo['description'] = trim(($seo['description'] ?? '') . ' — ' . $payload['vendor']);
}
$values = &$modx->event->returnedValues;
$values['seo'] = $seo;
break;
}