learndash_pdf_keywords

Description

Usage

add_filter( 'learndash_pdf_keywords', 'your_function_name', 10, 1 );

Return Value

The filtered value.

Examples

add_filter( 'learndash_pdf_keywords', 'my_learndash_custom_pdf_keywords', 10, 3 );
/**
 * Adds custom keywords to the PDF metadata for LearnDash certificates.
 *
 * This function demonstrates how to hook into the 'learndash_pdf_keywords'
 * filter to add specific keywords to the PDF document's metadata, enhancing
 * its searchability and organization.
 *
 * @param string $pdf_keywords The default PDF keywords generated by LearnDash.
 * @param TCPDF $pdf The TCPDF class instance.
 * @param int $cert_id The post ID of the certificate.
 *
 * @return string The modified PDF keywords string.
 */
function my_learndash_custom_pdf_keywords( $pdf_keywords, $pdf, $cert_id ) {
	// Get the certificate post object to access its details.
	$certificate_post = get_post( $cert_id );

	// Ensure we have a valid certificate post.
	if ( ! $certificate_post instanceof WP_Post ) {
		return $pdf_keywords; // Return original keywords if certificate is not found.
	}

	// Get the course ID associated with this certificate.
	$course_id = get_post_meta( $cert_id, 'course_id', true );

	// Construct our custom keywords.
	$custom_keywords = array();

	// Add the certificate title as a keyword.
	$custom_keywords[] = $certificate_post->post_title;

	// If a course ID is available, add the course title as a keyword.
	if ( ! empty( $course_id ) ) {
		$course_title = get_the_title( $course_id );
		if ( ! empty( $course_title ) ) {
			$custom_keywords[] = $course_title;
		}
	}

	// Get the user who earned the certificate.
	// This assumes a meta key like 'user_id' exists on the certificate post.
	$user_id = get_post_meta( $cert_id, 'user_id', true );
	if ( ! empty( $user_id ) ) {
		$user_info = get_userdata( $user_id );
		if ( $user_info instanceof WP_User ) {
			$custom_keywords[] = $user_info->display_name;
			$custom_keywords[] = $user_info->user_email;
		}
	}

	// Combine the original keywords with our custom keywords.
	// Ensure keywords are unique and separated by commas.
	$all_keywords = array_unique( array_merge( explode( ',', $pdf_keywords ), $custom_keywords ) );

	// Trim any whitespace from each keyword and remove empty ones.
	$cleaned_keywords = array_filter( array_map( 'trim', $all_keywords ) );

	// Return the final, comma-separated string of keywords.
	return implode( ',', $cleaned_keywords );
}

Placement

This code should be placed in the functions.php file of your active theme, a custom plugin, or using a code snippets plugin.

Source Code

src/includes/tcpdf-certificate-code.php:589

/**
		 * Filters the pdf keywords.
		 *
		 * @param string $pdf_keywords PDF keywords.
		 * @param TCPDF $pdf `TCPDF` class instance.
		 * @param int $cert_id Certificate post ID.
		 */
		$pdf->SetKeywords( apply_filters( 'learndash_pdf_keywords', $cert_args['pdf_keywords'], $pdf, $cert_args['cert_id'] ) );

		// Set header data
		if ( mb_strlen( $cert_args['cert_title'], 'UTF-8' ) < 42 ) {
			$header_title = $cert_args['cert_title'];
		} else {
			$header_title = mb_substr( $cert_args['cert_title'], 0, 42, 'UTF-8' ) . '...';
		}

Related Hooks

• learndash_pdf_author — fires_nearby
• learndash_pdf_subject — fires_nearby
• learndash_pdf_title — fires_nearby