使用来自子元素的数据在 php 中使用 simplexml 选择其他元素中的数据

Question

所以，我在 php 中使用 simplexml 将 xml 文件中的元素显示到网页上。当在某个元素中选择整个列表子元素时，这可以正常工作。 然而问题是，我需要在一个元素中选择多个规则，并显示附加到在另一个元素中找到的这些特定规则的数据。

澄清一下，这是我的 xml 文件的简化版本（它包含我需要的所有内容）：

<report>
    <profile_info>  
    <rules>

        <rule id="RUL1">
            <display_name>
            XMP does not have CreateDate entry in the XMP Basic Schema
            </display_name>
            <display_comment>
            This entry of the predefined XMP Basic Schema defines the date and time when the document has been created. It is required by some PDF-based ISO standards.
            </display_comment>
        </rule>

        <rule id="RUL133">
            <display_name>
            XMP does not have a VersionID entry in the XMP Media Management Schema
            </display_name>
            <display_comment>
            The VersionID in the XMP Media Management Schema (xmpMM) is the version identifier for respective resource. This entry is required by some PDF-based ISO standards for file identification.
            </display_comment>
        </rule>

        <rule id="RUL169">
            <display_name>
            Page does not have TrimBox or ArtBox
            </display_name>
            <display_comment>
            Either ArtBox or TrimBox should be defined for pages in a PDF file that are used in prepress. PDF/X ISO standards require the presence of one of these boxes.
            </display_comment>
        </rule>

    </rules>
</profile_info>


<results>
    <hits rule_id="RUL169" severity="Error">
    </hits>
    <hits rule_id="RUL133" severity="Error">
    </hits>
</results>
</report>

到目前为止，我可以使用 php 中的 simplexml 使用它们的 display_name 和 display_comment 来回显整个规则列表。

但这不是我想要的。我希望能够仅显示实际给出错误的规则的子元素，如根元素“结果”中所示。

总结一下我的问题：获取在<results> 中出现错误的规则的ID，并使用它们来显示另一个根元素<rules> 中显示的display_name 和display_comment。

这是我迄今为止列出的整个有效规则列表的 php 代码，如果有帮助的话。 （这行得通，但这不是我想要的）

<?php

    if(file_exists('../uploads/reports/report.xml')){
    $xml = simplexml_load_file('../uploads/reports/report.xml');
    } 
    else{
    exit('Could not load the file ...');
    }

foreach ($xml->profile_info as $profile_info){
    foreach ($profile_info->rules as $rules){
        foreach ($rules->rule as $rule){

                echo '<div id="name">'.$rule->display_name.'</div>'.'<div id="comment">'.$rule
                    ->display_comment.'</div>';
?>

提前致谢！

Answer 1

使用SimpleXMLElement::xpath和array_map函数的解决方案：

$xml = simplexml_load_file('../uploads/reports/report.xml');
...
$hits = $xml->xpath("results/hits/@rule_id");
$ruleIds = array_map(function($v){    // getting search path for each needed rule
    return "profile_info/rules/rule[@id='". (string)$v. "']"; 
}, $hits);

foreach ($xml->xpath(implode(" | ", $ruleIds)) as $rule) {
    echo '<div id="name">'. $rule->display_name .'</div>'.
         '<div id="comment">'. $rule->display_comment .'</div>';
}

“查看源”输出：

        <div id="name">
        XMP does not have a VersionID entry in the XMP Media Management Schema
        </div><div id="comment">
        The VersionID in the XMP Media Management Schema (xmpMM) is the version identifier for respective resource. This entry is required by some PDF-based ISO standards for file identification.
        </div><div id="name">
        Page does not have TrimBox or ArtBox
        </div><div id="comment">
        Either ArtBox or TrimBox should be defined for pages in a PDF file that are used in prepress. PDF/X ISO standards require the presence of one of these boxes.
        </div>