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);
SimpleXMLElement::__construct
(PHP 5, PHP 7, PHP 8)
SimpleXMLElement::__construct — Cria um novo objeto SimpleXMLElement
Descrição
final public SimpleXMLElement::__construct
( string
$data
, int $options = 0
, bool $data_is_url = false
, string $ns = ""
, bool $is_prefix = false
)Cria um novo objeto SimpleXMLElement.
Parâmetros
-
data -
Uma string XML bem formada ou, um caminho ou URL para um documento XML se
data_is_urlfortrue. -
options -
Opcionalmente utilizado para especificar parâmetros adicionais da Libxml.
-
data_is_url -
Por padrão,
data_is_urléfalse. Utilizetruepara especificar que o parâmetrodataé um caminho ou URL para um documento XML ao invés de string. -
ns -
Prefixo ou URI do namespace.
-
is_prefix -
truesensé um prefixo,falsese é uma URI; o padrão seráfalse.
Valor Retornado
Retorna um objeto SimpleXMLElement representando
data.
Erros
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 irá imprimir:
PHP: Behind the Parser
Exemplo #2 Cria um objeto SimpleXMLElement de uma URL
<?php
$sxe = new SimpleXMLElement('http://example.org/document.xml', NULL, TRUE);
echo $sxe->asXML();
?>
Changelog
| Versão | Descrição |
|---|---|
| 5.2.0 | Adicionado os parâmetros ns e is_prefix. |
| 5.1.2 | Adicionado os parâmetros options e data_is_url. |
Veja Também
- Basic usage
- simplexml_load_string() - Interpreta uma string XML e a transforma em um objeto
- simplexml_load_file() - Interpreta um arquivo XML e o transforma em um objeto
- Dealing with XML errors
- libxml_use_internal_errors() - Desabilita erros da libxml e permite que o usuário obtenha informação do erro como necessitar
add a note
User Contributed Notes 7 notes
ahmad dot mayahi at gmail dot com ¶
7 years ago
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.
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
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 $e){
echo 'Please try again later...';
exit();
}
?>
bertolini dot cedric at me dot com ¶
9 years ago
It's worth noting that the behavior of SimpleXmlElement::__construct is not exactly the same as simplexml_load_string, regarding libxml_use_internal_errors().
In my case,
<?php
libxml_use_internal_errors(true);
new \SimpleXmlElement($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.
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->$xml_field;
}
?>
uramihsayibok, gmail, com ¶
14 years ago
As I was filling out a bug report, I realized why (speculation here) the constructor is final: so that functions like simplexml_load_file and simplexml_load_string can work. I imagine the PHP-ized code looks something like
<?php
function simplexml_load_file($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.
