wordpress:如何使用ACF編寫PHP陣列以呈現作業發佈的JSON-LD標記

我想為我的wordpress頁面中的职業职位添加動態JSON-LD（schema.org）.我在下面尝試了此代碼.但是我想我在陣列中有一些語法錯誤.也许陣列中不允许使用" echo"？ 我希望有人可以帮助我吗？

<?php function schema() {?>
<?php if( have_rows('schema_auszeichnung') ): ?>
    <?php while( have_rows('schema_auszeichnung') ): the_row(); 
        // Get sub field values.
        $title = get_sub_field('title');
        $description = get_sub_field('description');
        $state = get_sub_field('state');
        $date = get_sub_field('date');
        $street = get_sub_field('street');
        $city = get_sub_field('city');
        $postalcode = get_sub_field('postalcode');

$schema = array(
    '@context'  => 'http://schema.org',
    '@type'     => 'JobPosting',
    'title'      => $title,
    'description' => $description,
    'hiringOrganization'   => array(
        '@type'           => 'Organization',
        'name'            => 'cent GmbH',
        'sameAs'          => get_home_url(),
        'logo'            => '/wp/wp-content/uploads/2016/11/cropped-logo.png'
    ),
    'employmentType'=> $state,
    'datePosted'    => $date,
    'validThrough'  => "",
    'jobLocation'   => array(
        '@type'     =>  "Place",
        'address'   => array (
            '@type' => 'PostalAddress',
            'streetAddress' => $street,
            'adressLocality' => $city,
            'postalCode' => $postalcode,
            'addressCountry' => 'DE'

        ),
    ),     

);
?>
<?php endwhile; ?>
<?php endif; ?>
<?php

echo '<script type="application/ld+json">' . json_encode($schema) . '</script>';
}
add_action('wp_head', 'schema');
?>

編輯：

删除" echo"後，我得到了php警告：未定義變數：模式.但是對我来說，它是在以下行中定義的：$ schema = array .....