PHP | SimpleXMLElement::__construct() Function

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

Reference: https://www.php.net/manual/en/simplexmlelement.construct.php