Gravity Forms - Add a {cookie} Merge Tag

gravity-forms-cookie-merge-tag.php

<?php

/**
 * Add a custom merge tag for Gravity Forms that allows you to display the value of a cookie.
 *
 * Usage: {cookie:cookie_name}
 *
 * @param string $text The text to be processed.
 * @param array $form The Form Object currently being processed.
 * @param array $entry The Entry Object currently being processed.
 * @param bool $url_encode Whether to encode any values found in the text.
 * @param bool $esc_html Whether to encode any values found in the text.
 * @param bool $nl2br Whether to convert new lines to <br> tags.
 * @param string $format The format requested for the text ('html', 'text' or 'url').
 *
 * @return string
 */
add_filter( 'gform_replace_merge_tags', function( $text, $form, $entry, $url_encode, $esc_html, $nl2br, $format ) {
	
	$custom_merge_tag_pattern = '/{cookie:([^}]*)}/';

	preg_match_all( $custom_merge_tag_pattern, $text, $matches, PREG_SET_ORDER );
	
	if ( ! $matches ) {
		return $text;
	}

	foreach ( $matches as $match ) {

		// Sanity check.
		if ( ! isset( $match[1] ) ) {
			continue;
		}

		// Extract the cookie name from the merge tag.
		$cookie_name = $match[1];

		if ( ! isset( $_COOKIE[ $cookie_name ] ) || '' === $_COOKIE[ $cookie_name ] ) {
			continue;
		}

		// Replace the merge tag with the sanitized cookie value.
		$text = str_replace( $match[0], esc_html( $_COOKIE[ $cookie_name ] ), $text );
	}

	return $text;
}, 10, 7 );