PHP - xmlwriter_write_dtd() Function

Definition and Usage

XML is a mark-up language to share the data across the web, XML is for both human read-able and machine read-able. XMLWriter extension internally has libxml xmlWriter API and is used to write/create the contents of an XML document. The XML documents generated by this are non-cached and forward-only.

The xmlwriter_write_dtd() function is used to create/write a full DTD tag.

Syntax

xmlwriter_start_dtd($writer, $name, $public_id, $system_id, $subset);

Parameters

Return Values

This function returns a boolean value which is TRUE in case of success and FALSE in case of failure.

PHP Version

This function was first introduced in PHP Version 5 and works in all the later versions.

Example

Following example demonstrates the usage of the xmlwriter_start_dtd() function −

<?php
   //Opening a writer
   $uri = "result.xml";
   $writer = xmlwriter_open_uri($uri);

   //Starting the document
   xmlwriter_start_document($writer);

   //Setting the indentation
   xmlwriter_set_indent($writer, TRUE);
   xmlwriter_set_indent_string($writer, "    ");

   $dtd = "<!DOCTYPE address [
      <!ELEMENT address (name,company,phone)>
      <!ELEMENT name (#PCDATA)>
      <!ELEMENT company (#PCDATA)>
      <!ELEMENT phone (#PCDATA)>
   ]>";

   //Creating a DTD tag
   xmlwriter_write_dtd($writer, 'test_dtd', 'pub_1001', 'sys_1001' , $dtd);

   //Starting an element
   xmlwriter_start_element($writer, 'address');

   //Starting a element tag
   xmlwriter_start_element($writer, 'name');
   
   //Adding text to the element
   xmlwriter_text($writer, 'Tanmay Patil');  
   xmlwriter_end_element($writer);
   xmlwriter_start_element($writer, 'company');
   
   //Adding text to the element
   xmlwriter_text($writer, 'TutorialsPoint');  
   xmlwriter_end_element($writer);
   xmlwriter_start_element($writer, 'phone');
   
   //Adding text to the element
   xmlwriter_text($writer, '(011) 123-4567');  
   xmlwriter_end_element($writer);

   //Ending the element
   xmlwriter_end_element($writer);

   //Ending the document
   xmlwriter_end_document($writer);
?> 

This will generate the following XML document −

<?xml version="1.0"?>
<!DOCTYPE test_dtd
PUBLIC "pub_1001" "sys_1001" [<!DOCTYPE address [
   <!ELEMENT address (name,company,phone)>
   <!ELEMENT name (#PCDATA)>
   <!ELEMENT company (#PCDATA)>
   <!ELEMENT phone (#PCDATA)>
]>]>
<address>
   <name>Tanmay Patil</name>
   <company>TutorialsPoint</company>
   <phone>(011) 123-4567</phone>
</address>

Example

Following is the example of this function in object oriented style −

<?php
   //Creating an XMLWriter
   $writer = new XMLWriter();

   //Opening a writer
   $uri = "result.xml";
   $writer->openUri($uri);

   //Starting the document
   $writer->startDocument();

   //Setting the indentation on
   $writer->setIndent(TRUE);
   
   //Setting the indentation
   $writer->setIndentString("    ");
   $dtd = "<!DOCTYPE address [
      <!ELEMENT address (name,company,phone)>
      <!ELEMENT name (#PCDATA)>
      <!ELEMENT company (#PCDATA)>
      <!ELEMENT phone (#PCDATA)>
   ]>";

   //Creating a DTD tag
   $writer->writeDtd('test_dtd', 'pub_1001', 'sys_1001' , $dtd);

   //Starting an element
   $writer->startElement(address);
   $writer->startElement('name');
   
   //Adding text to the element
   $writer->text('Tanmay Patil');  
   $writer->endElement();
   $writer->startElement('company');
   
   //Adding text to the element
   $writer->text('TutorialsPoint');  
   $writer->endElement();
   $writer->startElement('phone');
   
   //Adding text to the element
   $writer->text('(011) 123-4567');  
   $writer->endElement();

   //Ending the element
   $writer->endElement();
   
   //Ending the document
   $writer->endDocument();
?> 

This will generate the following XML document −

<?xml version="1.0"?>
<!DOCTYPE test_dtd
PUBLIC "pub_1001" "sys_1001" [<!DOCTYPE address [
   <!ELEMENT address (name,company,phone)>
   <!ELEMENT name (#PCDATA)>
   <!ELEMENT company (#PCDATA)>
   <!ELEMENT phone (#PCDATA)>
]>]>
<address>
   <name>Tanmay Patil</name>
   <company>TutorialsPoint</company>
   <phone>(011) 123-4567</phone>
</address>