php - 使用 XPath 选择/过滤 XML 元素

Question

这是我的亚马逊 mws api 响应

<?xml version="1.0"?>
<GetMyPriceForSKUResponse xmlns="http://mws.amazonservices.com/schema/Products/2011-10-01">
<GetMyPriceForSKUResult SellerSKU="ds-tru-6sss" status="Success">
  <Product xmlns="http://mws.amazonservices.com/schema/Products/2011-10-01" xmlns:ns2="http://mws.amazonservices.com/schema/Products/2011-10-01/default.xsd">
    <Identifiers>
      <MarketplaceASIN>
        <MarketplaceId>Assssssss</MarketplaceId>
        <ASIN>sss</ASIN>
      </MarketplaceASIN>
      <SKUIdentifier>
        <MarketplaceId>Afasrfd</MarketplaceId>
        <SellerId>ssssss</SellerId>
        <SellerSKU>dssss</SellerSKU>
      </SKUIdentifier>
    </Identifiers>
    <Offers>
      <Offer>
        <BuyingPrice>
          <LandedPrice>
            <CurrencyCode>USD</CurrencyCode>
            <Amount>12.49</Amount>
          </LandedPrice>
          <ListingPrice>
            <CurrencyCode>USD</CurrencyCode>
            <Amount>12.49</Amount>
          </ListingPrice>
          <Shipping>
            <CurrencyCode>USD</CurrencyCode>
            <Amount>0.00</Amount>
          </Shipping>
        </BuyingPrice>
        <RegularPrice>
          <CurrencyCode>USD</CurrencyCode>
          <Amount>12.49</Amount>
        </RegularPrice>
        <FulfillmentChannel>MERCHANT</FulfillmentChannel>
        <ItemCondition>New</ItemCondition>
        <ItemSubCondition>New</ItemSubCondition>
        <SellerId>Aadada</SellerId>
        <SellerSKU>ssss</SellerSKU>
      </Offer>
      <Offer>
        <BuyingPrice>
          <LandedPrice>
            <CurrencyCode>USD</CurrencyCode>
            <Amount>1000.00</Amount>
          </LandedPrice>
          <ListingPrice>
            <CurrencyCode>USD</CurrencyCode>
            <Amount>1000.00</Amount>
          </ListingPrice>
          <Shipping>
            <CurrencyCode>USD</CurrencyCode>
            <Amount>0.00</Amount>
          </Shipping>
        </BuyingPrice>
        <RegularPrice>
          <CurrencyCode>USD</CurrencyCode>
          <Amount>1000.00</Amount>
        </RegularPrice>
        <FulfillmentChannel>MERCHANT</FulfillmentChannel>
        <ItemCondition>New</ItemCondition>
        <ItemSubCondition>New</ItemSubCondition>
        <SellerId>ssss</SellerId>
        <SellerSKU>sss</SellerSKU>
      </Offer>
    </Offers>
  </Product>
</GetMyPriceForSKUResult>
<ResponseMetadata>
  <RequestId>e0ef1c2c-4f35-4316-8629-faadadd</RequestId>
</ResponseMetadata>
</GetMyPriceForSKUResponse>

并选择 amount (12.49)从

<ListingPrice>
    <CurrencyCode>USD</CurrencyCode>
    <Amount>12.49</Amount>
</ListingPrice>

我在尝试 ，

// from curl
$result = curl_exec ($ch);
$xmldoc = new DOMDocument();
$xmldoc->load($result);
$xpathvar = new Domxpath($xmldoc);

$queryResult = $xpathvar->query('/Amount');
foreach($queryResult as $result){
    echo $result;
}

我期望为此提供更多的值(value)，但我根本没有得到任何值(value)。

抱歉，我不擅长 XPath，有人可以指导我吗？

Answer 1

目前我在你的代码中发现了错误:

第一:用两个//选择一个元素，而不管它在 xml 树中的位置。

 $queryResult = $xpathvar->query('//Amount');

第二:感谢@Ranon。您将处理文档 xml 命名空间:

// Register Namespace mws
$xpathvar->registerNamespace("mws", 'http://mws.amazonservices.com/schema/Products/2011-10-01');

...并使用它，意味着:

 $queryResult = $xpathvar->query('//mws:Amount');

第三:如果要选择文本节点(在 <amount> 节点之间)，您应该使用:

$queryResult = $xpathvar->query('//mws:Amount/text()');

否则，您可以选择父元素 <Amount> (正如您已经在做的那样)并使用 PHP 检索该值。然后你必须将代码更改为:

$queryResult = $xpathvar->query('//mws:Amount');
foreach($queryResult as $result){
   echo $result->nodeValue; // echo the node value, not the node 'itself'
}

第四:还要注意代码中的另一个错误。当您从 xml 字符串创建 DOMDocument 时，您必须使用:

$document->loadXML($result);

第五:你说你要找回 <Amount>内部元素形成 <ListingPrice>元素。注意还有 <Amount>里面的元素 <RegularPrice>元素。所以它 有关系哪里 <Amount>元素位于树中。使用以下查询仅获取列表价格金额:

$queryResult = $xpathvar->query('//mws:ListingPrice/mws:Amount');