Add an A–Z Filter to the PMPro Member Directory

my-pmpro-member-directory-az-filter.php

<?php
/**
 * Add an A–Z filter navigation to the PMPro Member Directory.
 *
 * This recipe:
 * - Adds A–Z filter links above the directory
 * - Filters directory results by the first letter of display_name
 * - Includes an "All" reset filter
 * - Redirects back to the full directory if no results are found
 *
 * Requires the PMPro Member Directory Add On.
 *
 * You can add this recipe to your PMPro Customizations Plugin
 * or use the Code Snippets plugin.
 *
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */


/**
 * Output the A–Z filter navigation.
 */
function my_pmpro_directory_az_filter_nav() {

	$current_letter = isset( $_GET['letter'] )
		? strtoupper( sanitize_text_field( $_GET['letter'] ) )
		: '';

	// Only allow a single A–Z character.
	if ( ! preg_match( '/^[A-Z]$/', $current_letter ) ) {
		$current_letter = '';
	}

	$base_url = remove_query_arg( 'letter' );

	echo '<div class="pmpro-directory-az-filter">';

	// Inline styles for the filter nav.
	echo '<style>
		.pmpro-directory-az-filter {
			display: flex;
			flex-wrap: wrap;
			gap: 4px;
			margin-bottom: 1.25em;
		}

		.pmpro-directory-az-filter a {
			display: inline-block;
			padding: 4px 8px;
			border: 1px solid #ccc;
			border-radius: 3px;
			text-decoration: none;
			font-weight: 600;
			font-size: .9em;
		}

		.pmpro-directory-az-filter a.active,
		.pmpro-directory-az-filter a:hover {
			background: #333;
			color: #fff;
			border-color: #333;
		}
	</style>';

	// "All" link.
	$all_active = empty( $current_letter ) ? ' active' : '';

	printf(
		'<a href="%s" class="%s">%s</a>',
		esc_url( $base_url ),
		'all' . $all_active,
		esc_html__( 'All', 'pmpro-member-directory' )
	);

	// A–Z links.
	foreach ( range( 'A', 'Z' ) as $letter ) {

		$active_class = ( $current_letter === $letter ) ? ' active' : '';

		$url = add_query_arg( 'letter', $letter, $base_url );

		printf(
			'<a href="%s" class="%s">%s</a>',
			esc_url( $url ),
			esc_attr( $active_class ),
			esc_html( $letter )
		);
	}

	echo '</div>';
}
add_action( 'pmpro_member_directory_before', 'my_pmpro_directory_az_filter_nav', 5 );


/**
 * Filter Member Directory results by first letter.
 *
 * @param array $sql_parts SQL query parts.
 * @return array Modified SQL query parts.
 */
function my_pmpro_directory_az_filter_sql_parts( $sql_parts ) {

	$letter = isset( $_GET['letter'] )
		? strtoupper( sanitize_text_field( $_GET['letter'] ) )
		: '';

	// Bail if not a valid A–Z letter.
	if ( ! preg_match( '/^[A-Z]$/', $letter ) ) {
		return $sql_parts;
	}

	global $wpdb;

	$sql_parts['WHERE'] .= $wpdb->prepare(
		' AND u.display_name LIKE %s ',
		$wpdb->esc_like( $letter ) . '%'
	);

	return $sql_parts;
}
add_filter( 'pmpro_member_directory_sql_parts', 'my_pmpro_directory_az_filter_sql_parts', 10, 1 );


/**
 * Redirect back to the full directory if no matching profiles are found.
 */
function my_pmpro_directory_empty_redirect() {

	$letter = isset( $_GET['letter'] )
		? strtoupper( sanitize_text_field( $_GET['letter'] ) )
		: '';

	// Only run for valid A–Z filters.
	if ( ! preg_match( '/^[A-Z]$/', $letter ) ) {
		return;
	}

	$base_url = remove_query_arg( 'letter' );
	?>

	<script>
	document.addEventListener('DOMContentLoaded', function() {

		var errorNotice = document.querySelector('.pmpro_message.pmpro_error');

		if (
			errorNotice &&
			errorNotice.textContent.includes('No matching profiles found')
		) {
			setTimeout(function() {
				window.location.href = '<?php echo esc_url( $base_url ); ?>';
			}, 5000);
		}
	});
	</script>

	<?php
}
add_action( 'wp_footer', 'my_pmpro_directory_empty_redirect' );