如何在WordPress中使用XPath变量动态填充Schema？

问题背景 #

已为WordPress的company自定义文章类型配置了MovingCompany类型的Schema模板，同时有一组XPath规则用于提取页面中的企业信息，但不知道如何将XPath提取的内容自动填充到Schema的变量占位符中。

现有资源 #

XPath变量规则

xpath:movingcompany.name:body/main[1]/div[1]/div[1]/h1[1]
xpath:movingcompany.address:body/main[1]/div[2]/div[1]/div[1]/div[1]/p[2]/span[1]
xpath:movingcompany.image:body/main[1]/div[2]/div[1]/div[1]/div[2]/img[1]
xpath:movingcompany.aggregateRating.ratingValue:body/main[1]/div[1]/div[1]/div[1]/div[1]/span[1]/span[1]
xpath:movingcompany.aggregateRating.ratingCount:body/main[1]/div[1]/div[1]/div[1]/div[1]/span[1]/span[2]
xpath:movingcompany.aggregateRating.reviewCount:body/main[1]/div[1]/div[1]/div[1]/div[1]/span[1]/span[2]
xpath:movingcompany.openingHoursSpecification.opens:body/main[1]/div[9]/div[1]/div[1]/div[1]/table[1]/tbody[1]/tr[1]/td[2]/div[1]/span[1]
xpath:movingcompany.openingHoursSpecification.closes:body/main[1]/div[9]/div[1]/div[1]/div[1]/table[1]/tbody[1]/tr[1]/td[2]/div[1]/span[1]

Schema模板

{
  "@context": "https://schema.org/",
  "@type": "MovingCompany",
  "name": "{{movingcompany.name}}",
  "address": "{{movingcompany.address}}",
  "image": "{{movingcompany.image}}",
  "aggregateRating": {
    "@type": "AggregateRating",
    "ratingValue": "{{movingcompany.aggregateRating.ratingValue}}",
    "ratingCount": "{{movingcompany.aggregateRating.ratingCount}}",
    "reviewCount": "{{movingcompany.aggregateRating.reviewCount}}"
  },
  "openingHoursSpecification": {
    "@type": "OpeningHoursSpecification",
    "opens": "{{movingcompany.openingHoursSpecification.opens}}",
    "closes": "{{movingcompany.openingHoursSpecification.closes}}",
    "dayOfWeek": [
      "Monday",
      "Tuesday",
      "Wednesday",
      "Thursday",
      "Friday"
    ]
  }
}

集成解决方案 #

以下是在WordPress中实现XPath提取+Schema填充的具体步骤，代码可直接添加到主题的functions.php文件中：

1. 编写XPath内容提取函数

该函数负责接收文章ID和XPath表达式，解析文章内容并返回对应的值（处理文本和图片属性两种情况）：

function get_xpath_content($post_id, $xpath_expr) {
    // 获取文章内容
    $post_content = get_post_field('post_content', $post_id);
    if (empty($post_content)) return '';

    // 初始化DOM解析器
    libxml_use_internal_errors(true); // 忽略HTML解析警告
    $dom = new DOMDocument();
    $dom->loadHTML('<html><body>' . $post_content . '</body></html>');
    $xpath = new DOMXPath($dom);

    // 执行XPath查询
    $nodes = $xpath->query($xpath_expr);
    if ($nodes->length === 0) return '';

    $node = $nodes->item(0);
    // 判断是否是图片节点，提取src属性
    if ($node->nodeName === 'img') {
        return $node->getAttribute('src');
    }
    // 其他节点返回文本内容
    return trim($node->nodeValue);
}

2. 映射XPath与Schema字段

将XPath规则整理为关联数组，键对应Schema中的占位符名称，值为XPath表达式：

function get_schema_xpath_mapping() {
    return [
        'movingcompany.name' => 'body/main[1]/div[1]/div[1]/h1[1]',
        'movingcompany.address' => 'body/main[1]/div[2]/div[1]/div[1]/div[1]/p[2]/span[1]',
        'movingcompany.image' => 'body/main[1]/div[2]/div[1]/div[1]/div[2]/img[1]',
        'movingcompany.aggregateRating.ratingValue' => 'body/main[1]/div[1]/div[1]/div[1]/div[1]/span[1]/span[1]',
        'movingcompany.aggregateRating.ratingCount' => 'body/main[1]/div[1]/div[1]/div[1]/div[1]/span[1]/span[2]',
        'movingcompany.aggregateRating.reviewCount' => 'body/main[1]/div[1]/div[1]/div[1]/div[1]/span[1]/span[2]',
        'movingcompany.openingHoursSpecification.opens' => 'body/main[1]/div[9]/div[1]/div[1]/div[1]/table[1]/tbody[1]/tr[1]/td[2]/div[1]/span[1]',
        'movingcompany.openingHoursSpecification.closes' => 'body/main[1]/div[9]/div[1]/div[1]/div[1]/table[1]/tbody[1]/tr[1]/td[2]/div[1]/span[1]'
    ];
}

3. 生成并输出Schema JSON-LD

通过钩子在页面头部输出填充好的Schema，仅在company自定义文章类型的单页生效：

function output_moving_company_schema() {
    // 仅在company自定义文章类型单页执行
    if (!is_singular('company')) return;

    $post_id = get_the_ID();
    $mapping = get_schema_xpath_mapping();
    $schema_template = '{
        "@context": "https://schema.org/",
        "@type": "MovingCompany",
        "name": "{{movingcompany.name}}",
        "address": "{{movingcompany.address}}",
        "image": "{{movingcompany.image}}",
        "aggregateRating": {
            "@type": "AggregateRating",
            "ratingValue": "{{movingcompany.aggregateRating.ratingValue}}",
            "ratingCount": "{{movingcompany.aggregateRating.ratingCount}}",
            "reviewCount": "{{movingcompany.aggregateRating.reviewCount}}"
        },
        "openingHoursSpecification": {
            "@type": "OpeningHoursSpecification",
            "opens": "{{movingcompany.openingHoursSpecification.opens}}",
            "closes": "{{movingcompany.openingHoursSpecification.closes}}",
            "dayOfWeek": [
                "Monday",
                "Tuesday",
                "Wednesday",
                "Thursday",
                "Friday"
            ]
        }
    }';

    // 替换所有占位符
    foreach ($mapping as $placeholder_key => $xpath_expr) {
        $content = get_xpath_content($post_id, $xpath_expr);
        $schema_template = str_replace("{{$placeholder_key}}", $content, $schema_template);
    }

    // 输出JSON-LD
    echo '<script type="application/ld+json">' . $schema_template . '</script>';
}
add_action('wp_head', 'output_moving_company_schema');

注意事项 #

• 你的XPath中ratingCount和reviewCount指向同一个节点，opens和closes也指向同一个节点，若实际页面中这些值不同，需要调整XPath表达式。
• 如果文章内容的HTML结构发生变化，需要同步更新XPath规则，否则会提取失败。
• 可以添加错误处理逻辑，比如当某个字段提取为空时，移除对应的Schema属性，避免出现空值。

内容的提问来源于stack exchange，提问作者Nuriddin Gulamov