我试图通过在关联数组中获取节点及其属性的值来解析XML。在下面的类中，convert_simple_xml_element_object_into_array是用来做这项工作的。
但是发生了一件奇怪的事情。如果提供的输入是适当缩进的xml，则返回的关联数组是正确的。然而，如果传递一个非缩进的xml字符串，它返回一个不正确的关联数组，索引为空。原因是什么呢?
示例xml字符串:
<?xml version="1.0"?>
<StreamWebInfo><UserInfo Username="a@b.com" AccountId="19"/><JobInfo Id="594" QualifiedFilePath="https://s.com/main_DIS_23009_1_v_2_1c2_2011_08_30.mpd" ParentContainerType="0" ContainerType="10" EndTime="2016-10-05 11:45:09"/><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="320" Height="240" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="320" Height="240" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="320" Height="240" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="480" Height="368" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="480" Height="368" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="480" Height="368" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="480" Height="368" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="480" Height="368" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="864" Height="480" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="864" Height="480" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1280" Height="720" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1280" Height="720" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1280" Height="720" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1280" Height="720" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1920" Height="1088" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1920" Height="1088" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1920" Height="1088" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1920" Height="1088" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1920" Height="1088" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo><ProfileInfo><VideoTrackWebInfo CodecType="3" Width="1920" Height="1088" Bitrate="0" TrackDurationInMin="199" FeaturesUsed="0"/></ProfileInfo></StreamWebInfo>
具有方法:
的类<?php
class _xml_parser {
const EMPTY_STRING = '';
const MAX_RECURSION_DEPTH_ALLOWED = 200;
const SIMPLE_XML_ELEMENT_OBJECT_PROPERTY_FOR_ATTRIBUTES = '@attributes';
/**
* Get the SimpleXMLElement representation of the function input
* parameter that contains XML string. Convert the XML string
* contents to SimpleXMLElement type. SimpleXMLElement type is
* nothing but an object that can be processed with normal property
* selectors and (associative) array iterators.
*
* @param string $xmlStringContents
* @return SimpleXMLElement get_simple_xml_element returns a SimpleXMLElement object which
* contains an instance variable which itself is an associative array of
* several SimpleXMLElement objects.
*
*
* @version 1.0.0
*/
public static function get_simple_xml_element($xmlStringContents) {
$simpleXmlElementObject = self::EMPTY_STRING;
if('string' == gettype($xmlStringContents)) {
$simpleXmlElementObject = simplexml_load_string($xmlStringContents);
}
return $simpleXmlElementObject;
}
/**
* This function accepts a SimpleXmlElementObject as a single argument and
* converts the XML object into a PHP associative array.
* If the input XML is in tree (i.e. nested) format, this function will return an associative
* array (tree/nested) representation of that XML.
*
* Note: It is a recursive a function
*
* @param string $simpleXmlElementObject
* @param number $recursionDepth
*
* @return If everything is successful, it returns an associate array containing
* the data collected from the XML format. Otherwise, it returns null.
*
*
*/
public static function convert_simple_xml_element_object_into_array($simpleXmlElementObject, &$recursionDepth=0) {
// Keep an eye on how deeply we are involved in recursion.
if ($recursionDepth > self::MAX_RECURSION_DEPTH_ALLOWED) {
// Fatal error. Exit now.
return(null);
}
if ($recursionDepth == 0) {
if (!($simpleXmlElementObject instanceof SimpleXMLElement)) {
// If the external caller doesn't call this function initially
// with a SimpleXMLElement object, return now.
return(null);
} else {
// Store the original SimpleXmlElementObject sent by the caller.
// We will need it at the very end when we return from here.
$callerProvidedSimpleXmlElementObject = $simpleXmlElementObject;
}
}
if ($simpleXmlElementObject instanceof SimpleXMLElement) {
// Get a copy of the simpleXmlElementObject
$copyOfsimpleXmlElementObject = $simpleXmlElementObject;
// Get the object variables in the SimpleXmlElement object for us to iterate.
$simpleXmlElementObject = get_object_vars($simpleXmlElementObject);
}
// It needs to be an array of object variables.
if (is_array($simpleXmlElementObject)) {
// Initialize the result array.
$resultArray = array();
// Is the input array size 0? Then, we reached the rare CDATA text if any.
if (count($simpleXmlElementObject) <= 0) {
// Let us return the lonely CDATA. It could even be whitespaces.
return (trim(strval($copyOfsimpleXmlElementObject)));
}
// Let us walk through the child elements now.
foreach($simpleXmlElementObject as $key=>$value) {
// Uncomment the following block of code if XML attributes are
// NOT required to be returned as part of the result array.
/*
if((is_string($key)) && ($key == self::SIMPLE_XML_ELEMENT_OBJECT_PROPERTY_FOR_ATTRIBUTES)) {
continue;
}
*/
// Let us recursively process the current element we just visited.
// Increase the recursion depth by one.
$recursionDepth++;
$resultArray[$key] = self::convert_simple_xml_element_object_into_array($value, $recursionDepth);
// Decrease the recursion depth by one.
$recursionDepth--;
}
if ($recursionDepth == 0) {
// That is it. Heading to the exit now.
// Set the XML root element name as the root [top-level] key of
// the associative array that we are going to return to the caller of this
// recursive function.
$tempArray = $resultArray;
$resultArray = array();
$resultArray[$callerProvidedSimpleXmlElementObject->getName()] = $tempArray;
}
return ($resultArray);
} else {
// We are now looking at either the XML attribute text or
// the text between the XML tags.
return (trim(strval($simpleXmlElementObject)));
} // End of else
}
/**
* Converts XML to JSON
* @param SimpleXMLElement $simpleXmlElementObject
* @return JSON string
*
*/
public static function xml2json($simpleXmlElementObject) {
$json_from_xml = null;
if($simpleXmlElementObject instanceof SimpleXMLElement) {
$xml_map = self::convert_simple_xml_element_object_into_array($simpleXmlElementObject);
$json_from_xml = json_encode($xmlMap);
}
return $json_from_xml;
}
}
在上面的xml中，返回的数组有一个名为ProfileInfo的键，但它包含一个具有空键值对的映射。
在convert_simple_xml_element_object_into_array函数中，您必须检查没有属性的SimpleXMLElement对象是否有子对象。如果是这样，对于每一个子对象，都必须再次递归地调用convert_simple_xml_element_object_into_array。
用新代码替换旧代码应该会返回一个正确的数组:
旧代码:// Is the input array size 0? Then, we reached the rare CDATA text if any.
if (count($simpleXmlElementObject) <= 0) {
// Let us return the lonely CDATA. It could even be whitespaces.
return (trim(strval($copyOfsimpleXmlElementObject)));
}
// Is the input array size 0? Then, we reached the rare CDATA text if any.
if (count($simpleXmlElementObject) <= 0) {
//Check if the Object have children. If so, call again the function
if(($copyOfsimpleXmlElementObject instanceof SimpleXMLElement) && (count($copyOfsimpleXmlElementObject->children()) >=1)) {
foreach($copyOfsimpleXmlElementObject->children() as $child){
$recursionDepth++;
$resultArray[$child->getName()] = self::convert_simple_xml_element_object_into_array($child, $recursionDepth);
$recursionDetph--;
}
}
else{
// Let us return the lonely CDATA. It could even be whitespaces.
return (trim(strval($copyOfsimpleXmlElementObject)));
}
}