$nonce, 'ajaxurl' => $ajax_url, 'loading_text' => esc_html__( 'Loading...', 'air-quality-mk' )); // localize script wp_localize_script( 'ajax-public', 'air_quality_mk_ajax', $script ); } add_action( 'wp_enqueue_scripts', 'air_quality_mk_ajax_enqueue_scripts' ); // process ajax request function air_quality_mk_ajax_public_handler() { // check nonce check_ajax_referer( 'air-quality-mk-widget', 'nonce' ); // define station id $station_id = isset( $_POST['station_id'] ) ? intval( $_POST['station_id'] ) : false; // end processing wp_die( air_quality_mk_ajax_display_markup($station_id) ); } // ajax hook for logged-in users: wp_ajax_{action} add_action( 'wp_ajax_public_hook', 'air_quality_mk_ajax_public_handler' ); // ajax hook for non-logged-in users: wp_ajax_nopriv_{action} add_action( 'wp_ajax_nopriv_public_hook', 'air_quality_mk_ajax_public_handler' ); // display markup function air_quality_mk_ajax_display_markup( $station_id ) { global $air_quality_mk_station_list_name; global $air_quality_mk_parameter_list_name; $station_name = $air_quality_mk_station_list_name[$station_id]; $measurments = air_quality_mk_ajax_get_last_data_for_station($station_id); $content = '

'; foreach ($measurments as $measurment) { $parameter_name = $air_quality_mk_parameter_list_name[$measurment->parameter]; $content .= $parameter_name . ': ' . $measurment->value . ' date: ' . $measurment->date_time . '
'; } return $content . '

'; } function air_quality_mk_ajax_get_last_data_for_station($station_id) { global $wpdb; global $air_quality_mk_measurements_table_name; $measurements_table_name = $wpdb->prefix . $air_quality_mk_measurements_table_name; $query = "SELECT * FROM wp_air_quality_mk_measurements as m inner join ( SELECT parameter, MAX(date_time) as date_time FROM wp_air_quality_mk_measurements WHERE station_id = %d group by station_id, parameter ) as p on m.parameter = p.parameter AND m.date_time = p.date_time WHERE station_id = %d"; $prepared_query = $wpdb->prepare( $query, $station_id, $station_id ); $measurments = $wpdb->get_results( $prepared_query ); if ( null !== $measurments ) return $measurments; else return array(); // empty array }