TImestamp comparison

gistfile1.txt

/**
 * Compare the import date (timestamp) with an existing post meta date.
 *
 * @param $continue_import bool
 * @param $post_id         int
 * @param $data            array
 * @param $import_id       int
 *
 * @return bool|mixed
 */
function dm_filter_by_date( $continue_import, $post_id, $data, $import_id ) {

	$import_id = absint( $import_id );
	
	if ( ! in_array( $import_id, array( 121, 124 ) ) ) {
		return $continue_import;
	}

	// Bail if no post ID.
	if ( empty( $post_id ) ) {
		return $continue_import;
	}

	// Retrieve meta which appears to already be stored as a timestamp.
	$existing_timestamp = get_post_meta( $post_id, 'wpcf-letzteaenderung', true );

	// Skip if existing date does not
	if ( empty( $existing_timestamp ) ) {
		return $continue_import;
	}

	// Change this to whatever field you want to compare against.
	$import_field = 'letzteaenderung';

	// Verify we have an actual valid data and field.
	if ( ! empty( $data ) && isset( $data[ $import_field ] ) ) {

		// Change 'import' field to a Unix timestamp.
		$import_timestamp = strtotime( $data[ $import_field ] );

		// Compare file date with existing date.
		if ( $import_timestamp > $existing_timestamp ) {

			// Create or update record if file date >= target date.
			return true;

		} else {

			// Do not create or update the record otherwise.
			return false;

		}

	}

	// Do nothing if it's not our target import.
	return $continue_import;
}

add_filter( 'wp_all_import_is_post_to_update', 'dm_filter_by_date', 10, 4 );