PHP 7.2 xml domdocument 获取给定子节点的节点值具有属性等于的兄弟节点值

Question

我有以下xml

<ReviseInventoryStatusResponse xmlns="urn:ebay:apis:eBLBaseComponents">
  <Timestamp>2019-01-02T15:42:31.495Z</Timestamp>
  <Ack>Warning</Ack>
  <Errors>
    <ShortMessage>Requested StartPrice and Quantity revision is redundant.</ShortMessage>
    <LongMessage>The existing price and quantity values are identical to those specified in the request and, therefore, have not been modified.</LongMessage>
    <ErrorCode>21917091</ErrorCode>
    <SeverityCode>Warning</SeverityCode>
    <ErrorParameters ParamID="ItemID">
      <Value>770386906435</Value>
    </ErrorParameters>
    <ErrorParameters ParamID="SKU">
      <Value/>
    </ErrorParameters>
    <ErrorClassification>RequestError</ErrorClassification>
  </Errors>
  <Errors>
    <ShortMessage>Requested StartPrice and Quantity revision is redundant.</ShortMessage>
    <LongMessage>The existing price and quantity values are identical to those specified in the request and, therefore, have not been modified.</LongMessage>
    <ErrorCode>21917091</ErrorCode>
    <SeverityCode>Warning</SeverityCode>
    <ErrorParameters ParamID="ItemID">
      <Value>770386906436</Value>
    </ErrorParameters>
    <ErrorParameters ParamID="SKU">
      <Value/>
    </ErrorParameters>
    <ErrorClassification>RequestError</ErrorClassification>
  </Errors>
  ...
  </ReviseInventoryStatusResponse>

我需要获取在 ErrorParameters/Value 中找到的给定 ItemID 的 ShortMessage，其中 ParamID="ItemID"

我已经能够检查是否存在具有给定值的节点：

$xmlr = new DOMDocument();
$xmlr->load('ReviseInventoryStatusResponse_error.xml');
$xpath = new DOMXPath($xmlr);
$xpath->registerNamespace('e', 'urn:ebay:apis:eBLBaseComponents');
$nodeExists=($xpath->query('//e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]')->length>0)?1:0;

然后我尝试通过

获取它的 ShortMessage

$xpath->query('//e:Errors[e:ErrorParameters@ParamID="ItemID"]/e:Value[.="770386906435"]/e:ShortMessage')

但是由于没有找到组合过滤器的正确方法，所以得到了预期的无效谓词。

能否请教正确的方法？

谢谢

Answer 1

这里有几种方法

Select Errors 元素节点使用嵌套条件：
//e:Errors[e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]]/e:ShortMessage
Select Value 元素并使用 parent 轴
//e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]/parent::*/parent::*/e:ShortMessage
Select Value 元素并使用 ancestor 轴
//e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]/ancestor::e:Errors/e:ShortMessage

如果您使用 DOMXpath::evaluate()，您可以使用 count() 和 string() 直接获取标量值。您甚至可能不需要检查节点是否存在，因为在这种情况下结果将是一个空字符串。

$document = new DOMDocument();
$document->loadXML($xml);
$xpath = new DOMXPath($document);
$xpath->registerNamespace('e', 'urn:ebay:apis:eBLBaseComponents');
$nodeExists = $xpath->evaluate(
  'count(//e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]) > 0'
);

var_dump($nodeExists);

$shortMessage = $xpath->evaluate(
  'string(//e:Errors[e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]]/e:ShortMessage)'
);
var_dump($shortMessage);

$shortMessage = $xpath->evaluate(
  'string(//e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]/parent::*/parent::*/e:ShortMessage)'
);
var_dump($shortMessage);

$shortMessage = $xpath->evaluate(
  'string(//e:ErrorParameters[@ParamID="ItemID"]/e:Value[. = "770386906435"]/ancestor::e:Errors/e:ShortMessage)'
);
var_dump($shortMessage);

输出：

bool(true) 
string(56) "Requested StartPrice and Quantity revision is redundant." 
string(56) "Requested StartPrice and Quantity revision is redundant." 
string(56) "Requested StartPrice and Quantity revision is redundant."

Answer 2

如果您使用 XPath 获取短信，检查是否有短信的快速方法是检查是否有任何查询结果...

$smgs = $xpath->query('//e:Errors[e:ErrorParameters[@ParamID="ItemID" and e:Value="7720386906435"]]/e:ShortMessage');
if ( count($smgs) > 0 ) {
    echo $smgs[0]->nodeValue;
}
else {
    echo "does not exist";
}

PHP 7.2 xml domdocument 获取给定子节点的节点值具有属性等于的兄弟节点值

PHP 7.2 xml domdocument get nodevalue of given childnode value of sibling having attribute equal to

php

xml

xpath

domdocument