Generate XML file in PHP SimpleXML DOM Reader/Writer Method

Generate XML file dynamically using PHP three different method,

• DOM
• XML Reader/Writer
• SimpleXML

Following table explain which are the good method to follow the standard and which are not.

Operation	DOM	XML Reader/Writer	SimpleXML
Read			Poorly support
Write			Poorly support
Manipulate		Poorly support	Poorly support
Full Control
Namespace Support			Poorly support
XPATH Support
Validate

DOM (Document Object Model) XML Method

DOM Advantages

• Very fast for small document, load entire document into memory.
• Simple PHP DOM interface.
• Access anything in tree, traversed in multitude of way.
• XML parsing library, libXML2 use for a DOM.

DOM Disadvantages

• Load entire document into memory.
• Data access only after completely document parsed.
• Support PHP 5+ or later version.

Create XML using DOM

<?php
  $dom = new DOMDocument('1.0','UTF-8');
  $dom->formatOutput = true;

  $root = $dom->createElement('student');
  $dom->appendChild($root);

  $result = $dom->createElement('result');
  $root->appendChild($result);

  $result->setAttribute('id', 1);
  $result->appendChild( $dom->createElement('name', 'Opal Kole') );
  $result->appendChild( $dom->createElement('sgpa', '8.1') );
  $result->appendChild( $dom->createElement('cgpa', '8.4') );

  echo '<xmp>'. $dom->saveXML() .'</xmp>';
  $dom->save('result.xml') or die('XML Create Error');
?>

Result Output

<?xml version="1.0" encoding="UTF-8"?>
<student>
  <result id="1">
    <name>Opal Kole</name>
    <sgpa>8.1</sgpa>
    <cgpa>8.4</cgpa>
  </result>
</student>

Manipulate XML using DOM

Manipulate above created XML file.

<?php
  $dom = new DOMDocument();
  $dom->formatOutput = true;

  $dom->load('result.xml', LIBXML_NOBLANKS);

  $root = $dom->documentElement;
  $newresult = $root->appendChild( $dom->createElement('result') );

  $newresult->setAttribute('id', 2);
  $newresult->appendChild( $dom->createElement('name','Max Miller') );
  $newresult->appendChild( $dom->createElement('sgpa','8.7') );
  $newresult->appendChild( $dom->createElement('cgpa','8.2') );

  echo ''. $dom->saveXML() .'';
  $dom->save('new_result.xml') or die('XML Manipulate Error');
?>

Result Output

result.xml

<?xml version="1.0" encoding="UTF-8"?>
<student>
  <result id="1">
    <name>Opal Kole</name>
    <sgpa>8.1</sgpa>
    <cgpa>8.4</cgpa>
  </result>
  <result id="2">
    <name>Max Miller</name>
    <sgpa>8.7</sgpa>
    <cgpa>8.2</cgpa>
  </result>
</student>

Read XML using DOM

<?php
  $dom = new DOMDocument();
  $dom->load('new_result.xml');

  $root = $dom->documentElement;
  echo "This document is store " . $root->tagName . " Result Information" . "";

  $results = $root->getElementsByTagName( 'result' );
  foreach( $results  as $result){
    echo 'Result Id: ' . $result->getAttribute('id');
    foreach( $result->getElementsByTagName('name') as $name ){
        echo ' Student ' . $name->nodeValue;
    }
    foreach( $result->getElementsByTagName('sgpa') as $sgpa ){
        echo ' SGPA ' . $sgpa->nodeValue;
    }
    foreach( $result->getElementsByTagName('cgpa') as $cgpa ){
        echo ' CGPA ' . $cgpa->nodeValue . "";
    }
  }
?>

Result Output

new_result.xml

This document is store student Result Information
Result Id: 1 Student Opal Kole SGPA 8.1 CGPA 8.4
Result Id: 2 Student Max Miller SGPA 8.7 CGPA 8.2

XML Reader/Writer Method

XML Reader/Writer Advantages

• Uses little memory for reading and writing.
• Allowing for accessing immediately.
• Support PHP4+ and PHP5+.

XML Reader/Writer Disadvantages

• Reading data only sequential.
• All method are slow for accessing data.

XML Reader Example

<?php
  $reader = new XMLReader();
  $reader->open('new_result.xml');

  while( $reader->read() ){
    if($reader->nodeType !== XMLReader::ELEMENT){
      continue;
    }
    if($reader->localName === 'result'){
      echo 'Result Id: ' . $reader->getAttribute('id');
    }
    if($reader->localName === 'name'){
      echo ' Student ' . $reader->readString();
    }
    if($reader->localName === 'sgpa'){
      echo ' SGPA ' . $reader->readString();
    }
    if($reader->localName === 'cgpa'){
      echo ' CGPA ' . $reader->readString() . "";;
    } 
  }
?>

Result Output

Result Id: 1 Student Opal Kole SGPA 8.1 CGPA 8.4
Result Id: 2 Student Max Miller SGPA 8.7 CGPA 8.2

XML Writer Example

<?php
  $writer = new XMLWriter();
  $writer->openUri('result.xml');

  $writer->setIndentString('  ');
  $writer->setIndent(true);

  $writer->startDocument( '1.0', 'UTF-8' );
  $writer->startElement('student');

  $writer->startElement('result');
  $writer->writeAttribute('id', '1');

  $writer->writeElement('name', 'Opal Kole');
  $writer->writeElement('sgpa', '8.1');
  $writer->writeElement('cgpa', '8.4');
  $writer->endElement();   /* </result> */

  $writer->flush();
  $writer->endElement();  /* </student> */
  $writer->endDocument();
?>

Result Output

result.xml

<?xml version="1.0" encoding="UTF-8"?>
<student>
  <result id="1">
    <name>Opal Kole</name>
    <sgpa>8.1</sgpa>
    <cgpa>8.4</cgpa>
  </result>
</student>

SimpleXML Reading/Writing

SimpleXML Writing

<?php
  $simple_xml = new SimpleXMLElement('<student></student>');

  $simple_xml->addChild('result');
  $simple_xml->result[0]->addAttribute('id', 1);

  $simple_xml->result[0]->addChild('name', 'Opal Kole');
  $simple_xml->result[0]->addChild('sgpa', '8.1');
  $simple_xml->result[0]->addChild('cgpa', '8.4');

  $simple_xml->asXML('simple_xml_create.xml');
?>

Result Output

simple_xml_create.xml

<?xml version="1.0"?>
<student><result id="1"><name>Opal Kole</name><sgpa>8.1</sgpa><cgpa>8.4</cgpa></result></student>

SimpleXML Reading

<?php
  $simple_xml = simplexml_load_file('simple_xml_create.xml');

  foreach( $simple_xml->result as $result){
    echo 'Result Id: ' . $result['id'] . 
      ' Student ' . $result->name .
      ' SGPA ' . $result->sgpa .
      ' CGPA ' . $result->cgpa . "";
  }
?>

Result Output

Result Id: 1 Student Opal Kole SGPA 8.1 CGPA 8.4