PHP | SimpleXMLElement::__construct() Function

Last Updated : 02 May, 2023

Pre-requisite:XML The __construct() function is an inbuilt function in PHP that is used to create a new SimpleXMLElement object for XML.

Syntax:

SimpleXMLElement::__construct( $data, $options, $data_is_url, $namespace, $is_prefix )

Parameters: This function accepts five parameters as mentioned above and described below:

$data: It is a required parameter. It specifies a well-formed XML string or the path or URL to an XML document file if $data_is_url is TRUE.
$options: It is an optional parameter. It specifies additional Libxml parameters. Is set by specifying the option and 1 or 0
$data_is_url: It is an optional parameter. Its default value is False. If the value of this parameter is True, it specifies that the data is a path/URL to a file of XML document instead of a string.
$namespace: It is an optional parameter. It specifies the namespace URI or prefix.
$is_prefix: It is an optional parameter of Boolean type. It specifies True if ns is a prefix and False if ns is a URI. The default value is False.

Return Value: It returns a SimpleXMLElement object that represents the XML structured data

Note: This function is available for PHP 5.0.1 and newer versions.

Example

php

<?php
 
// Loading XML document to $user
$user = <<<XML
<user>
<username> user123 </username>
<name> firstname lastname </name>
<phone> +91-XXXXXXXXXX </phone>
<detail> I am John Doe. Live in Kolkata, India. </detail>
</user>
XML;
 
// Creating new SimpleXMLElement
// object from $user
$xml = new SimpleXMLElement($user);
 
// Printing as XML
echo $xml->asXML();
 
?>

Output:

user123 firstname lastname +91-XXXXXXXXXX I am John Doe. Live in Kolkata, India.

Output in browser as source:

Example: Loading XML document from file or url. sample.xml

html

<?xml version="1.0"?>
<user>
<username> user123 </username>
<name> firstname lastname </name>
<phone> +XX-XXXXXXXXXX</phone>
<detail> I am John Doe. Live in Kolkata, India. </detail>
</user>

index.php

php

<?php
 
// Loading XML document from sample.xml to $user
// and creating new SimpleXMLElement object
$xml = new SimpleXMLElement("sample.xml", 0, TRUE);
 
// Printing data as xml document
echo $xml->asXML();
 
?>

Output:

user123 firstname lastname +91-XXXXXXXXXX I am John Doe. Live in Kolkata, India.

Output in browser as a source:

Possible values of the parameter $option are:

LIBXML_COMPACT – Nodes allocation optimization activated
LIBXML_DTDATTR – This option sets default DTD attributes
LIBXML_DTDLOAD – Load subset externally
LIBXML_DTDVALID – Validate the xml document with the DTD
LIBXML_DOTTED_VERSION – Get libxml version dot separated
LIBXML_ERR_ERROR – Get errors(recoverable)
LIBXML_ERR_FATAL – Get errors(fatal)
LIBXML_ERR_NONE – Get no errors
LIBXML_ERR_WARNING – Get warnings(simple)
LIBXML_NOBLANKS – Remove all blank nodes in the XML document
LIBXML_NOCDATA – Merge new CDATA as text nodes
LIBXML_NOEMPTYTAG – Expand empty tags
LIBXML_NOENT – Substitute entities in XML document
LIBXML_NOERROR – restrict error report
LIBXML_NONET – Disables network access while loading the XML documents
LIBXML_NOWARNING – restricts warning reports
LIBXML_NOXMLDECL – Drops the XML declaration when saving the document
LIBXML_NSCLEAN – Removes all redundant namespace declarations
LIBXML_PARSEHUGE – Sets XML_PARSE_HUGE flag, which removes any hardcoded limit from the parser which again affects limits like the size of text nodes and maximum depth of a document
LIBXML_XINCLUDE – Substitution of implements XInclude
LIBXML_VERSION – Get the LIBXML version in integer format