Add a discount code field to a PMPro Shortcode Signup form.

discount-code-field-for-signup-shortcode.php

<?php
/**
 * This recipe creates a discount code field for a specific level
 * when using the Signup Shortcode for membership registration.
 *
 * This can be helpful when a level requires a discount code for registration, or
 * if the Signup Shortcode level is a paid level and you have a discount code that
 * makes this level free.
 *
 * This recipe assumes the following:
 *
 * 1. The level for the Signup Shortcode is level 2. You should change this to your
 *    level's ID in the 'levels' option for the field, e.g. 'levels' => array( 3 ),
 * 2. The Signup Shortcode is configured to show custom fields.
 *    e.g. [pmpro_signup level="2" custom_fields="true"]
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_pmpro_discount_code_for_signup_shortcode() {

	// Don't break if PMPro is out of date or not loaded.
	if ( ! function_exists( 'pmpro_add_user_field' ) || pmpro_is_checkout() || ! function_exists( 'pmprosus_signup_shortcode' ) ) {
		return;
	}

	// define the fields
	$fields   = array();
	$fields[] = new PMPro_Field(
		'discount_code', // input field name, used as meta key
		'text',         // field type
		array(
			'id'             => 'signup-discount-code',
			'label'          => 'Discount Code', // display custom label, if not used field name will be used
			'html_attributes' => array( 'required' => 'required' ),
			'levels'          => array( 2 ), // levels to display field for
			'class'          => 'discount_code', // custom class for input field
			'memberslistcsv' => true, // include when using export members to csv
			'addmember'      => true, // include when using add member from admin
			'required'        => true, // make field required
		)
	);

	foreach ( $fields as $field ) {
		pmpro_add_user_field(
			'signup-shortcode', // location on checkout page
			$field     // PMProRH_Field object
		);
	}
	unset( $field );

	// that's it. see the PMPro Register Helper readme for more information and examples.
}
add_action( 'init', 'my_pmpro_discount_code_for_signup_shortcode' );

// Remove signup-shortcode location when we're on the checkout page.
function remove_signup_shortcode_discount_code_field_where( $where, $field ) {
	if ( 'signup-shortcode' === $where && 'discount_code' === $field->name && pmpro_is_checkout() ) {
		return false;
	}

	return $where;
}
add_filter( 'pmpro_add_user_field_where', 'remove_signup_shortcode_discount_code_field_where', 10, 2 );

function my_pmpro_extend_is_checkout( $is_checkout ) {
	global $pmpro_pages;

	if ( $is_checkout ) {
		return $is_checkout;
	}

	if ( ! $is_checkout && ! empty( $pmpro_pages['checkout'] ) ) {
		// Get the current page slug
		$checkout_page_slug = get_post_field( 'post_name', $pmpro_pages['checkout'] );

		// If the URL contains the checkout page slug, set $is_checkout to true
		if ( ! empty( $checkout_page_slug ) && strpos( $_SERVER['REQUEST_URI'], $checkout_page_slug ) !== false ) {
			$is_checkout = true;
		}
	}

	return $is_checkout;
}
add_filter( 'pmpro_is_checkout', 'my_pmpro_extend_is_checkout' );