PHP SimpleXML XML method of operation

SimpleXML Introduction

SimpleXML extension provides a very simple and easy to use tool set, can XML object into a general attribute selector and having an array of iterators.

For example XML

XML structure section quoted from << -depth understanding of PHP >>, and in order to illustrate the use of a method, a number of seemingly fundamental force increase with irrational structure

I will finish with the XML structure:

• Generate XML operations
• Read XML operations
• XML update operations
• Delete XML operations

<?xml version="1.0" encoding="utf-8"?>
<collection xmlns:lan="language">
    <php:book xmlns:php="php">
        <php:title php:edition="3">PHP Advanced and Object-Oriented Programming: Visual QuickPro Guide</php:title>
        <author:author xmlns:author="LarryUllman">Larry Ullman</author:author>
        <php:year>2012</php:year>
        <php:pages>612</php:pages>
        <php:chapterArr>
          <php:chapter php:number="12">PHP's Command-Line Interface</php:chapter>
          <php:chapter php:number="13">XML and PHP</php:chapter>
          <php:chapter php:number="14">Debugging, Testing, and Performance</php:chapter>
        </php:chapterArr>
        <php:cover php:fileName="phpvqp3.jpg"/>
    </php:book>
    <js:book xmlns:js="javascript">
        <js:title>Modern JavaScript: Develop and Design</js:title>
        <author:author  xmlns:author="LarryUllman">Larry Ullman</author:author>
        <js:year>2012</js:year>
        <js:pages>504</js:pages>
        <js:chapterArr>
          <js:chapter js:number="1" js:pages="24">(Re-)Introducing JavaScript</js:chapter>
          <js:chapter js:number="2" js:pages="32">JavaScript in Action</js:chapter>
          <js:chapter js:number="3" js:pages="34">Tools of the Trade</js:chapter>
        </js:chapterArr>
    </js:book>
</collection>

Class methods and functions

In practice (add, delete, change, check) before XML, briefly explain the methods and functions corresponding to the function included SimpleXML, if you have some knowledge about this, you can skip this section, looking directly at: generate XML operations , read XML operations , updating XML operation , remove the XML operation example.

** PS: This article is not a detailed description of the functions and parameters of methods and functions (as far as possible reflect already in operation), To learn more, please refer to the official website . **

method

• addAttribute add a property to SimpleXML element
• SimpleXML addChild to add a child node node
• asXML not return a syntax error XML string based on SimpleXML object
• element attributes to identify all of the properties
• It returns the children of a given node's child
• __construct create SimpleXML object initialization method
• count the number of elements calculated subnode
• getDocNamespaces Gets the namespace of the XML document stated
• getName Gets the element name SimpleXML node
• getNamespaces get used XML namespace document
• registerXPathNamespace for the XPath query or create a namespace prefix
• saveXML asXML alias
• __toString magic method returns the string contents of the node SimpleXML
• run a query xpath xpath

function

• simplexml_import_dom converting a DOM object to a target SimpleXML
• simplexml_load_file to parse an XML file into a SimpleXML objects
• simplexml_load_string a string object is parsed into a SimpleXML

SimpleXML manipulate XML

Generate XML

<?php 
//定义数据
$bookArr = [
    [
        'book'  => [
            'value' => null,
            'attr'  => [
                'nsKey'     => 'program:xmlns:php',
                'nsVal'     => 'php',
            ],
        ],
        'title'     =>
        [
            'value' => 'PHP Advanced and Object-Oriented Programming: Visual QuickPro Guide',
            'attr'  => [
                'edition' => 3
            ]
        ],
        'author'    => 'Larry Ullman',
        'year'      => 2012,
        'pages'     => 612,
        'chapterArr'=>
        [
            [
                'value' => 'PHP&apos;s Command-Line Interface',
                'attr'  => ['number'=>12]
            ],
            [
                'value' => 'XML and PHP',
                'attr'  => ['number'=>13]
            ],
            [
                'value' => 'Debugging, Testing, and Performance',
                'attr'  => ['number'=>14]
            ],
        ],
        'cover'   => [
            'attr'    => ['fileName'=>'phpvqp3.jpg'],
        ]
    ],
    [
        'book'  => [
            'value'  => null,  
            'attr'   => [
                'nsKey' => 'program:xmlns:js',
                'nsVal' => 'javascript',
            ]
        ],
        'title'     => ['value'=>'Modern JavaScript: Develop and Design'],
        'author'    => 'Larry Ullman',
        'year'      => 2012,
        'pages'     => 504,
        'chapterArr'=> [
            [
                'value' => '(Re-)Introducing JavaScript',
                'attr'  => ['number'=>1, 'pages'=>24]
            ],
            [
                'value' => 'JavaScript in Action',
                'attr'  => [ 'number'=>2, 'pages'=>32]
            ],
            [
                'value' => 'Tools of the Trade',
                'attr'  => ['number'=>3,'pages'=>34]
            ]
        ]
    ]
];

//用一段字符串生成一个XML的root节点
$statement = '<?xml version="1.0" encoding="utf-8"?><collection xmlns:lan="language"></collection>';
$rootXML = simplexml_load_string($statement); //等价于 $rootXML = new SimpleXMLElement($statement);

foreach($bookArr as $book){
    //获取数组中定义的节点的命名空间，如program:xmlns:php，则php为元素的前缀
    $tempPrefix = substr($book['book']['attr']['nsKey'],strpos($book['book']['attr']['nsKey'], ':') + 1);
    $prefix = $tempPrefix ? $tempPrefix . ':' : '';

    //为root节点添加一个带有指定命名空间的book节点
    $bookNode = $rootXML->addChild($prefix.'book',$book['book']['value']);

    //定义book节点的命名空间及前缀
    $bookNode->addAttribute($book['book']['attr']['nsKey'],$book['book']['attr']['nsVal']);

    //为book节点添加一个带有指定命名空间，指定值的title节点
    $titleNode = $bookNode->addChild($prefix.'title',$book['title']['value']);

    //为title节点增加指定命名空间及属性
    if(!empty($book['title']['attr'])){
        foreach($book['title']['attr'] as $k => $v){
            $titleNode->addAttribute($prefix.$k,$v);
        }
    }

    //为book节点添加一个子节点author及值
    $authorNode = $bookNode->addChild('author',$book['author']);
    //为author节点设置命名空间及前缀
    $authorNode->addAttribute('program:xmlns:author','LarryUllman');

    //为book节点添加一个子节点year及值
    $bookNode->addChild($prefix.'year',$book['year']);

    //为book节点添加一个子节点pages及值
    $bookNode->addChild($prefix.'pages',$book['pages']);

    //为book节点增加一个指定命名空间的chapterArr节点
    $chapterArr = $bookNode->addChild($prefix.'chapterArr');

    //为chapterArr节点增加一个指定命名空间，指定值指定属性的chapter节点
    if(!empty($book['chapterArr'])){
        foreach($book['chapterArr'] as $value){
            $chapterNode = $chapterArr->addChild($prefix.'chapter',$value['value']);
            if(!empty($value['attr'])) {
                foreach ($value['attr'] as $k => $v) {
                    $chapterNode->addAttribute($prefix . $k, $v);
                }
            }
        }
    }

    //为book节点增加一个子节点带有指定命名空间的cover，并设置其属性
    if(!empty($book['cover']['attr']['fileName'])){
        $coverNode = $bookNode->addChild($prefix.'cover',null);
        $coverNode->addAttribute($prefix.'fileName',$book['cover']['attr']['fileName']);
    }

}

//设置header头
header('content-type:text/xml;');
//格式化输出SimpleXML对象
$xmlStr = $rootXML->asXML(); //也可保存到文件 $rootXML->asXML('/path/to/filename.xml');
echo $xmlStr;

Read XML

//给定XML
$xmlStr = <<<XML
<?xml version="1.0" encoding="utf-8"?>
<collection xmlns:lan="language">
    <php:book xmlns:php="php">
        <php:title php:edition="3">PHP Advanced and Object-Oriented Programming: Visual QuickPro Guide</php:title>
        <author:author xmlns:author="LarryUllman">Larry Ullman</author:author>
        <php:year>2012</php:year>
        <php:pages>612</php:pages>
        <php:chapterArr>
          <php:chapter php:number="12">PHP's Command-Line Interface</php:chapter>
          <php:chapter php:number="13">XML and PHP</php:chapter>
          <php:chapter php:number="14">Debugging, Testing, and Performance</php:chapter>
        </php:chapterArr>
        <php:cover php:fileName="phpvqp3.jpg"/>
    </php:book>
    <js:book xmlns:js="javascript">
        <js:title>Modern JavaScript: Develop and Design</js:title>
        <author:author  xmlns:author="LarryUllman">Larry Ullman</author:author>
        <js:year>2012</js:year>
        <js:pages>504</js:pages>
        <js:chapterArr>
          <js:chapter js:number="1" js:pages="24">(Re-)Introducing JavaScript</js:chapter>
          <js:chapter js:number="2" js:pages="32">XML and PHP</js:chapter>
          <js:chapter js:number="3" js:pages="34">Debugging, Testing, and Performance</js:chapter>
        </js:chapterArr>
    </js:book>
</collection>
XML;

$rootXML = simplexml_load_string($xmlStr,null,null,'js',true);////等价于 $rootXML = new SimpleXMLElement($xmlStr,null,false,'js',true);

$data = [];

foreach($rootXML->book as $book){

    $data[$key]['title']   = (string)$book->title; //title值
    $data[$key]['edition'] = (string)$book->title['edition'];//title的edition属性值
    
    //获取book节点下命名空间前缀为author的子节点
    $author = $book->children('author',true);//
    $data[$key]['author'] = (string)$author;//author值
    
    $data[$key]['year'] = (int)$book->year;//year值
    $data[$key]['pages'] = (int)$book->pages;//pages值

    //多种获取属性的方式 开始
    $i = 0;
    foreach($book->chapterArr[0] as $chapter) {
        $data[$key]['chapterArr'][$i]['value'] = (string)$chapter;//chapter值
        //获取chapter节点的number，pages属性
        foreach ($chapter->attributes('js', true) as $chapterKey => $chapterVal) {
            $data[$key]['chapterArr'][$i]['attr'][$chapterKey] = (int)$chapterVal;
        }
        //$data[$key]['chapterArr'][$i]['attr']['number'] = (int)$chapter['number'];//也可这么获取number属性
        //$data[$key]['chapterArr'][$i]['attr']['pages'] = (int)$chapter['pages'];//也可这么获取pages属性
        $i++;
    }

    /*
    //获取chapterArr子节点个数，然后循环获取值及属性
    $chapterNum = $book->chapterArr[0]->count();
    for($i=0;$i<$chapterNum;$i++) {
        $data[$key]['chapterArr'][$i]['value'] = (string)$book->chapterArr->chapter[$i];chapter值
        $data[$key]['chapterArr'][$i]['attr']['number'] = (int)$book->chapterArr->chapter[$i]['number'];number属性
        $data[$key]['chapterArr'][$i]['attr']['pages'] = (int)$book->chapterArr->chapter[$i]['pages'];pages属性
    }
    */
    
    /*
    通过xpath获取属性
    $chapterArr = $bookNode->xpath('//js:book//js:chapterArr//js:chapter');
    $i=0;
    foreach($chapterArr as $k=>$v){
      $data[$key]['chapterArr'][$i]['value'] = (string)$v;
      foreach($attr = $v->attributes('js',true) as $k=>$v){
        $data[$key]['chapterArr'][$i]['attr'][$k] = (int)$v;
      }
      $i++;
    }
    */

    //多种获取属性的方式 结束
    
    //cover值
    $fileName = (string)($book->cover['fileName']) && $data[$key]['cover']['attr']['fileName'] = $fileName;
    
}

var_dump($data);die;

Updating XML

//$xmlStr如上
$rootXML = simplexml_load_string($xmlStr,null,null,'js',true);////等价于 $rootXML = new SimpleXMLElement($xmlStr,null,false,'js',true);

//更新标题及chapter的值及属性
$rootXML->book->title = 'modifyXML';
$chapterArrNode = $rootXML->book->chapterArr[0];
$i = 1;
foreach($chapterArrNode as $chapter){
    $chapter[0]           = 'chapter'.$i;//修改值
    $chapter['number'] = 'number'.$i;//修改number属性
    $chapter['pages']  = 'pages'.$i;//修改pages属性
    $i++;
}

//设置header头
header('content-type:text/xml;');
//格式化输出SimpleXML对象
$xmlStr = $rootXML->asXML(); //也可保存到文件 $rootXML->asXML('/path/to/filename.xml');
echo $xmlStr;

Delete XML

//$xmlStr如上
$rootXML = simplexml_load_string($xmlStr,null,null,'js',true);////等价于 $rootXML = new SimpleXMLElement($xmlStr,null,false,'js',true);

//删除year
unset($rootXML->book->year);

//删除最后chapter标签
unset($rootXML->book->chapterArr[0]->chapter[2]);

//删除第一个chapter的pages属性
unset($rootXML->book->chapterArr[0]->chapter[0]['pages']);

//使用xpath删除number为2的chapter标签
$rootXML->registerXPathNamespace('js','javascript');
foreach($rootXML->xpath('//js:book//js:chapterArr//js:chapter[@js:number=2]') as $chapter2)
{
    unset($chapter2[0]);
}

//设置header头
header('content-type:text/xml;');
$xmlStr = $rootXML->asXML(); //也可保存到文件 $rootXML->asXML('/path/to/filename.xml');
echo $xmlStr;