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SimpleXMLElement::__construct

(PHP 5, PHP 7, PHP 8)

SimpleXMLElement::__construct Cria um novo objeto SimpleXMLElement

Descrição

public SimpleXMLElement::__construct(
    string $data,
    int $options = 0,
    bool $dataIsURL = false,
    string $namespaceOrPrefix = "",
    bool $isPrefix = false
)

Cria um novo objeto SimpleXMLElement.

Parâmetros

data

Uma string XML bem formada ou, um caminho ou URL para um documento XML se dataIsURL for true.

options

Opcionalmente utilizado para especificar parâmetros adicionais da Libxml, que afetam a leitura de documentos XML. Opções que afetam a saída de documentos XML (por exemplo, LIBXML_NOEMPTYTAG) é ignorada silenciosamente.

Nota:

Pode ser necessário passar LIBXML_PARSEHUGE para poder processar XML profundamente aninhados ou nós de texto muito grandes.

dataIsURL

Por padrão, dataIsURL é false. Utilize true para especificar que o parâmetro data é um caminho ou URL para um documento XML ao invés de string.

namespaceOrPrefix

Prefixo ou URI do namespace.

isPrefix

true se namespaceOrPrefix é um prefixo, false se é uma URI; o padrão será false.

Erros/Exceções

Produz uma mensagem de erro E_WARNING para cada erro encontrado nos dados do XML e, adicionalmente, dispara uma Exception se as informações no XML não puderem ser interpretadas.

Dica

Utilize a função libxml_use_internal_errors() para suprimir todos os erros XML, e a função libxml_get_errors() para iterá-los, depois.

Exemplos

Nota:

Os exemplos listados podem incluir o arquivo example.php, que referem-se a uma string XML encontrada no primeiro exemplo do guia de uso básico.

Exemplo #1 Cria um objeto SimpleXMLElement

<?php

include 'example.php';

$sxe = new SimpleXMLElement($xmlstr);
echo
$sxe->movie[0]->title;

?>

O exemplo acima produzirá:

PHP: Behind the Parser

Exemplo #2 Cria um objeto SimpleXMLElement de uma URL

<?php

$sxe
= new SimpleXMLElement('http://example.org/document.xml', 0, true);
echo
$sxe->asXML();

?>

Veja Também

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User Contributed Notes 8 notes

up
9
rowan dot collins at gmail dot com
7 years ago
The manual doesn't really explain what the $ns argument (and the accompanying $is_prefix) are for.

What they do is similar to the ->children() method: they set the context of the returned object to that namespace, so that access via ->elementName and ['attributeName'] refer to elements and attributes in that namespace.

In particular, they do *not* change the namespaces which exist on the document.

See this example:

<?php
// This XML contains two elements called <child>
// One is in the namespace http://example.com, with local prefix 'ws'
// The other has no namespace (no prefix, and no default namespace declared)
$xml = '<ws:example xmlns:ws="http://example.com"><child>Not in namespace</child><ws:child>In example namespace</ws:child></ws:example>';

$sx0 = new SimpleXMLElement($xml, 0, false);
$sx1 = new SimpleXMLElement($xml, 0, false, 'http://example.com');
$sx2 = new SimpleXMLElement($xml, 0, false, 'ws', true);

echo
"
Without:
{$sx0->child}
By namespace:
{$sx1->child}
By prefix:
{$sx2->child}
"
;
?>

Output:

Without: Not in namespace
By namespace: In example namespace
By prefix: In example namespace
up
9
tudor at culise dot net
16 years ago
This class is extendable, but it's too bad that its constructor cannot be overriden (PHP says it's a final method). Thus the class should be wrapped using the delegation principle rather that extended.
up
5
info at ensostudio dot ru
2 years ago
Extended SimpleXMLElement:
<?php
class XmlElement extends \SimpleXMLElement
{
public static function
factory(string $root): self
{
return new static(
'<?xml version="1.0" encoding="UTF-8"?><'.$root.'/>', LIBXML_BIGLINES | LIBXML_COMPACT);
}

/**
* @param iterable $attributes An array of element attributes as name/value pairs
* @return $this
*/
public function addAttributes(iterable $attributes)
{
foreach (
$attributes as $name => $value) {
$this->addAttribute($name, $value);
}

return
$this;
}

/**
* @param string $name The sub-element name
* @param string|array|null $valueOrAttributes The sub-element value or an array of attributes
* @param string|null $namespace The sub-element namespace
* @return static|null
*/
public function addChild($name, $valueOrAttributes = null, $namespace = null)
{
if (
is_array($valueOrAttributes)) {
$child = parent::addChild($name, null, $namespace);
foreach (
$valueOrAttributes as $name => $value) {
$child->addAttribute($name, $value);
}
} else {
$child = parent::addChild($name, $valueOrAttributes, $namespace);
}

return
$child;
}

/**
* @param iterable $childs An array of sub-elements as name/value(or attributes) pairs
* @return $this
*/
public function addChilds(iterable $childs)
{
foreach (
$childs as $name => $value) {
$this->addChild($name, $value);
}

return
$this;
}
}
?>
up
6
ahmad dot mayahi at gmail dot com
8 years ago
You won't be able to load an XML file without root element:

//This will throw an exception
$xml = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?>', null, false);

//Here is the solution
$xml = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><root></root>', null, false);
up
4
bertolini dot cedric at me dot com
10 years ago
It's worth noting that the behavior of SimpleXmlElement::__construct is not exactly the same as simplexml_load_string, regarding libxml_use_internal_errors().

In my case,

<?php
libxml_use_internal_errors
(true);
new
\SimpleXmlElement($data);
?>

was still throwing error. But as soon as I switched to

<?php
libxml_use_internal_errors
(true);
simplexml_load_string($data);
?>

everything worked fine and I stopped getting an error.
up
5
kumarldh at gmail dot com
13 years ago
Using libxml_use_internal_errors() may suppress errors but Exception still requires decent handling. I used following code snippet.

<?php
libxml_use_internal_errors
(true);
try{
$xmlToObject = new SimpleXMLElement($notSoWellFormedXML);
} catch (
Exception $e){
echo
'Please try again later...';
exit();
}
?>
up
0
uramihsayibok, gmail, com
14 years ago
As I was filling out a bug report, I realized why (speculation here) the constructor is final: so that functions like simplexml_load_file and simplexml_load_string can work. I imagine the PHP-ized code looks something like

<?php

function simplexml_load_file($filename, $class_name = "SimpleXMLElement", $options = 0, $ns = "", $is_prefix = false) {
return new
$class_name($filename, $options, true, $ns, $is_prefix);
}

?>

If we were to use a different $class_name and change the constructor's definition these functions wouldn't work.

There's no easy, sensible solution that keeps simplexml_load_file and simplexml_load_string.
up
-1
Phil Cross
9 years ago
It's worth noting, that you need to typecast dynamic property names to string in order to retrieve there value, for example:

<?php
$xml
= new SimpleXMLElement('records.xml', 0, true);

// This will work as expected because its a hard coded property value
foreach($xml as $record){
echo
$record->id; // Will output the ID fine
}

// Dynamic properties require typecasting to string
$xml_field = 'id';
foreach(
$xml as $record){

// This will dump a SimpleXMLElement object
var_dump($record->$xml_field);

// This will output the value as expected
echo (string)$record->$xml_field;
}
?>
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