Phoenix.View.render_to_string如何使用布局渲染模板？

Question

渲染模板工作正常：

//----------------------------------------------------------------------------------
//Below is the custom Javascript hook for Historic Extract
//----------------------------------------------------------------------------------
function price_history() {
    $handle = 'hist_extract';
    $list = 'enqueued';

    if (wp_script_is( $handle, $list )) {
        return;
    }
    else
    {  
        // registering and enqueueing the Javascript/Jquery
        wp_enqueue_script('jquery');
        wp_register_script('hist_extract', get_template_directory_uri() . '/js/Historic_Price.js', array( 'jquery' ), NULL, false );
        wp_enqueue_script('hist_extract');
        wp_localize_script('hist_extract', 'MyAjax1', array(
            // URL to wp-admin/admin-ajax.php to process the request
            'ajaxurl' => admin_url('admin-ajax.php'),
            // generate a nonce with a unique ID "myajax-post-comment-nonce"
            // so that you can check it later when an AJAX request is sent
            'security' => wp_create_nonce('my-special-string')
        ));

        error_log('Js for Historic Price loaded successfully');
        error_log(admin_url('admin-ajax.php'));
    }
}

add_action('wp_enqueue_scripts', 'price_history');

//----------------------------------------------------------------------------------
// Custom function that handles the AJAX hook for Historic Extract
//----------------------------------------------------------------------------------
function historic_data_extract() {
    error_log('Start of report data function on ajax callback');
    // check_ajax_referer( 'my-special-string', 'security' );
    $from_date = $_POST['fromdate'];
    $to_date = $_POST['todate'];
    $convert_from_date= date("Y-m-d", strtotime($from_date));
    $convert_to_date = date("Y-m-d", strtotime($to_date));
    error_log($from_date );
    error_log($to_date);
    error_log($convert_from_date);
    error_log($convert_to_date);
    //******************************************
    //Custom Code for fetching data from server database
    //********************************************

    //header("Content-Type: application/json; charset=UTF-8");

    define("dbhost", "localhost");
    define("dbuser", "xxxxxxxxx");
    define("dbpass", "xxxxxxxxx");
    define("db", "xxxxxxxx");

    $emparray = array();
    $conn = mysqli_connect(dbhost, dbuser, dbpass, db);
    // Change character set to utf8
    mysqli_set_charset($conn,"utf8");

    if ($conn )
    {
        $query = "SELECT PR_PRICE_HIST_TBL.PR_PRODUCT_ID,PR_PRICE_HIST_TBL.PR_URL_ID,PR_PRICE_HIST_TBL.PR_SHOP_NAME,PR_PRICE_HIST_TBL.PR_LAST_CHECKED,PR_PRICE_HIST_TBL.PR_CUST_PROD_CODE,PR_PRICE_HIST_TBL.PR_PRODUCT_NAME,PR_PRICE_HIST_TBL.PR_LAST_PRICE,PR_PRICE_HIST_TBL.PR_CONV_PRICE,PR_PRICE_HIST_TBL.PR_DOMAIN,PR_PRICE_HIST_TBL.PR_COUNTRY_CODE,PR_PRICE_HIST_TBL.PR_AVAILABLE,PR_PRICE_HIST_TBL.PR_AVAIL_DESCR,PR_PRICE_HIST_TBL.PR_PRICE_TIME,PR_PRICE_HIST_TBL.PR_FAULT_FLAG,PR_PRICE_HIST_TBL.PR_FAULT_TIME,PR_PRICE_HIST_TBL.PR_FAULT_MSG,TABLE_72.MIN_PRICE,TABLE_72.MAX_PRICE,TABLE_72.AVG_PRICE,TABLE_72.DEV_PRICE
                  FROM PR_PRICE_HIST_TBL
                  INNER JOIN TABLE_72 ON   PR_PRICE_HIST_TBL.PR_URL_ID=TABLE_72.PR_URL_ID AND
                  PR_PRICE_HIST_TBL.PR_SHOP_NAME=TABLE_72.PR_SHOP_NAME   AND
                  PR_PRICE_HIST_TBL.PR_PRODUCT_NAME=TABLE_72.PR_PRODUCT_NAME
                  AND PR_PRICE_HIST_TBL.PR_LAST_CHECKED BETWEEN '$convert_from_date' AND '$convert_to_date';";
        error_log($query);
        $result_select= mysqli_query($conn,$query);
        error_log(mysqli_num_rows($result_select));
        error_log(mysqli_error($conn));

        while($row = mysqli_fetch_assoc($result_select))
        {   
            error_log(json_encode($row)); 
            $emparray[] = $row;

        }

        //error_log(json_encode($emparray));

        echo json_encode($emparray);
        die();
    }
}

add_action('wp_ajax_hist_extract', 'historic_data_extract');
add_action('wp_ajax_nopriv_hist_extract', 'historic_data_extract');

...但是我想使用布局渲染此视图。我该如何实现？