Woocommerce - Validation on cart page - wordpress

Question

I have a custom filed for specific shipping methods (see screenshot).
Is there a hook/action to validate this field before proceeding the checkout. When I set the field to required the validation will fire at the checkout page but I want it at the cart page.
Validation:
//Validate the custom selection field
add_action('woocommerce_checkout_process', 'carrier_company_checkout_validation');
function carrier_company_checkout_validation() {
Load settings and convert them in variables
extract( custom_field_settings() );
if( isset( $_POST[$field_id] ) && empty( $_POST[$field_id] ) )
wc_add_notice(
sprintf( __("Please select a %s as it is a required field.","woocommerce"),
'<strong>' . $label_name . '</strong>'
), "error" );
}
** UPDATE: **
like #LoicTheAztec mentioned here the complete code.
Everything is working fine. The custom input value from cart will be shown on checkout and saved in the DB after order confirmation. But I don't know where I have to put the validation on the cart page when the custom input is empty because everything on cart is on ajax.
// ##########################################
// Add custom fields to a specific selected shipping method
// ##########################################
// Custom function that handle your settings
function delivery_date_settings(){
return array(
'field_id' => 'delivery_date', // Field Id
'field_type' => 'text', // Field type
'field_label' => 'label text', // Leave empty value if the first option has a text (see below).
'label_name' => __("Lieferdatum","woocommerce"), // for validation and as meta key for orders
);
}
// Display the custom checkout field
add_action( 'woocommerce_after_shipping_rate', 'carrier_company_custom_select_field', 20, 2 );
function carrier_company_custom_select_field( $method, $index ) {
if( $method->id == 'flat_rate:2' || $method->id == 'free_shipping:1') {
extract( delivery_date_settings() ); // Load settings and convert them in variables
$chosen = WC()->session->get('chosen_shipping_methods'); // The chosen methods
$value = WC()->session->get($field_id);
$value = WC()->session->__isset($field_id) ? $value : WC()->checkout->get_value('_'.$field_id);
$options = array(); // Initializing
$chosen_method_id = WC()->session->chosen_shipping_methods[ $index ];
if($chosen_method_id == 'flat_rate:2' || $method->id == 'free_shipping:1' ){
echo '<div class="custom-date-field">';
woocommerce_form_field( $field_id, array(
'type' => $field_type,
'label' => $field_label, // Not required if the first option has a text.
'class' => array('form-row-wide datepicker ' . $field_id . '-' . $field_type ),
'required' => false,
), $value );
echo '</div>';
// Jquery: Enable the Datepicker
?>
<script language="javascript">
jQuery( function($){
$('.datepicker input').datepicker({
dateFormat: 'dd.mm.yy', // ISO formatting date
});
});
</script>
<?php
}
}
}
// jQuery code (client side) - Ajax sender
add_action( 'wp_footer', 'carrier_company_script_js' );
function carrier_company_script_js() {
// Only cart & checkout pages
if( is_cart() || ( is_checkout() && ! is_wc_endpoint_url() ) ):
// Load settings and convert them in variables
extract( lieferdatum_settings() );
$js_variable = is_cart() ? 'wc_cart_params' : 'wc_checkout_params';
// jQuery Ajax code
?>
<script type="text/javascript">
jQuery( function($){
if (typeof <?php echo $js_variable; ?> === 'undefined')
return false;
$(document.body).on( 'change', 'input#<?php echo $field_id; ?>', function(){
var value = $(this).val();
$.ajax({
type: 'POST',
url: <?php echo $js_variable; ?>.ajax_url,
data: {
'action': 'delivery_date',
'value': value
},
success: function (result) {
console.log(result); // Only for testing (to be removed)
}
});
});
});
</script>
<?php
endif;
}
// The Wordpress Ajax PHP receiver
add_action( 'wp_ajax_delivery_date', 'set_carrier_company_name' );
add_action( 'wp_ajax_nopriv_delivery_date', 'set_carrier_company_name' );
function set_carrier_company_name() {
if ( isset($_POST['value']) ){
// Load settings and convert them in variables
extract( delivery_date_settings() );
if( empty($_POST['value']) ) {
$value = 0;
$label = 'Empty';
} else {
$value = $label = esc_attr( $_POST['value'] );
}
// Update session variable
WC()->session->set( $field_id, $value );
// Send back the data to javascript (json encoded)
echo $label;
die();
}
}
// Save custom field as order meta data
add_action( 'woocommerce_checkout_create_order', 'save_carrier_company_as_order_meta', 30, 1 );
function save_carrier_company_as_order_meta( $order ) {
// Load settings and convert them in variables
extract( delivery_date_settings() );
if( isset( $_POST[$field_id] ) && ! empty( $_POST[$field_id] ) ) {
$order->update_meta_data( '_'.$field_id, esc_attr($_POST[$field_id]) );
WC()->session->__unset( $field_id ); // remove session variable
}
}
// Display custom field in admin order pages
add_action( 'woocommerce_admin_order_data_after_shipping_address', 'admin_order_display_carrier_company', 30, 1 );
function admin_order_display_carrier_company( $order ) {
// Load settings and convert them in variables
extract( delivery_date_settings() );
$carrier = $order->get_meta( '_'.$field_id ); // Get carrier company
if( ! empty($carrier) ) {
// Display
echo '<p><strong>' . $label_name . '</strong>: ' . $carrier . '</p>';
}
}
// Display carrier company after shipping line everywhere (orders and emails)
add_filter( 'woocommerce_get_order_item_totals', 'display_carrier_company_on_order_item_totals', 1000, 3 );
function display_carrier_company_on_order_item_totals( $total_rows, $order, $tax_display ){
// Load settings and convert them in variables
extract( delivery_date_settings() );
$carrier = $order->get_meta( '_'.$field_id ); // Get carrier company
if( ! empty($carrier) ) {
$new_total_rows = [];
// Loop through order total rows
foreach( $total_rows as $key => $values ) {
$new_total_rows[$key] = $values;
// Inserting the carrier company under shipping method
if( $key === 'shipping' ) {
$new_total_rows[$field_id] = array(
'label' => $label_name,
'value' => $carrier,
);
}
}
return $new_total_rows;
}
return $total_rows;
}

Answer 1

I think the hook you're looking for is woocommerce_check_cart_items, that's the one that validates the cart items before proceeding to checkout.
I'm not 100% sure whether you'll be able to get the field in the same way using $_POST but it's worth a go.