PHP with XMLDequan Chen and Narith Kun

---Term Project---

for

WSU 2010 Summer Course - CS366

Emails: dequanchen2007@gmail.com

NKun08@winona.edu

Project Outline• Introduction• What’s PHP?• History of PHP Supporting XML• PHP SimpleXML Functions• PHP DOM Parser• PHP XML Expat Parser• Conclusion• Demo 1 - PHP Processes a simple XML file• Demo 2 - PHP Processes a complex XML (our

HWK2 XML) file• References

Introduction• XML is now a widely accepted and used

standard or a set of rules for encoding documents in a machine-readable form.

• XML support was taken more seriously in PHP 5 (2004) than it was in PHP 4 (2000) and PHP 3 (1998).

- In this presentation we will focus on the XML support in PHP 5 – the latest version PHP 5.3.2.

What’s PHP?

• Hypertext Preprocessor, a popular general-purpose server-side scripting language which can be embedded into HTML. It was originally designed to produce dynamic web pages. But PHP can now create a wide variety of mini or large-scale complex applications.

- Note: PHP name is derived from Personal Home Page Tools or PHP/FI (as in PHP/FI 1.0 and 2.0).

History of PHP Supporting XML

• PHP 3 – SAX (Simple API for XML) parser (Expat parser)

• PHP 4 – SAX + DOMXML

( non-standard, API-breaking, memory leaking, incomplete functionality)

• PHP 5 – SAX + DOM + SimpleXML (Re-written from scratch)

PHP SimpleXML Functions

• SimpleXML handles the most common XML tasks

• It is an easy way of getting an element's attributes and text content

• SimpleXML just takes a few lines of code to read text data from an element (Compared to DOM and the Expat parser)

PHP SimpleXML Functions

SimpleXML Functions:• simplexml_import_dom — Get a

SimpleXMLElement object from a DOM node.

• simplexml_load_file — Interprets an XML file into an object

• simplexml_load_string — Interprets a string of XML into an object

PHP SimpleXML Functions

SimpleXMLElement Class:• SimpleXMLElement::addAttribute — Adds an

attribute to the SimpleXML element • SimpleXMLElement::addChild — Adds a child

element to the XML node • SimpleXMLElement::asXML — Return a well-

formed XML string based on SimpleXML element • SimpleXMLElement::attributes — Identifies an

element's attributes (…to be continued…)

PHP SimpleXML Functions

SimpleXMLElement Class:• SimpleXMLElement::children — Finds children

of given node • SimpleXMLElement::__construct — Creates a

new SimpleXMLElement object • SimpleXMLElement::count — Counts the

children of an element • SimpleXMLElement::getDocNamespaces —

Returns namespaces declared in document (…to be continued…)

PHP SimpleXML Functions

SimpleXMLElement Class:• SimpleXMLElement::getName — Gets the

name of the XML element • SimpleXMLElement::getNamespaces — Returns

namespaces used in document • SimpleXMLElement::registerXPathNamespace —

Creates a prefix/ns context for the next XPath query

• SimpleXMLElement::xpath — Runs XPath query on XML data

PHP SimpleXML CodeFor parsing a XML file:<?php$xml = simplexml_load_file("test2.xml");

displayChildrenRecursive($xml);echo "<br />"; (…to be continued…)

echo $xml->getName() . ": ";echo $xml->getName() . ": ";foreach($xml->attributes() as $Attr) {foreach($xml->attributes() as $Attr) { echo $Attr->getName()."=".$Attr." ";echo $Attr->getName()."=".$Attr." ";}}

PHP SimpleXML Codefunction displayChildrenRecursive($xmlObj,$depth=0){

foreach($xmlObj->children() as $child) { echo "<br/>"; echo str_repeat('-',$depth).$child->getName().": ".

$child." "; foreach($child->attributes() as $attr) { echo str_repeat('',$depth).$attr- >getName()."=".

$attr." "; } displayChildrenRecursive($child,$depth+1); }}

How Does The Code Work?1. Load the XML file 2. Get the name & attributes of the root

element 3. Create a recursive function with a foreach

loop that will trigger on each child node, using the children() function

4. For each child node: use getName() method for each element name to be displayed; use a foreach loop to get the attribute nodes for each child node, using the attributes() function .

5. For each attribute use getName() method for the name to be displayed.

PHP XML DOM Parser

• The DOM parser is an tree-based parser.• Tree-based parser: It transforms an XML

document into a tree structure. It analyzes the whole document, and provides access to the tree elements

• Good for small and medium-sized XML files (loading the whole file into the memory)

PHP XML DOM Parser• <?xml version="1.0" encoding="ISO-

8859-1"?><from>Jani</from>

• The XML DOM parses the XML above as follows: – Level 1: XML Document – Level 2: Root element tag: <from> – Level 3: Root element content: "Jani"

DOM Document Functions• There are many: (http://www.php.net/manual/en/class.domdocument.php)

• DOMDocument::__construct — Creates a new DOMDocument object

• DOMDocument::load — Load XML from a file

• DOMDocument::saveXML — Dumps the internal XML tree back into a string

DOM Element Functions• There are many: (http://www.php.net/manual/en/class.domelement.php)

• DOMElement::__construct — Creates a new DOMElement object

• DOMElement::getAttribute — Returns value of attribute

• DOMElement::getAttributeNode — Returns attribute node

PHP XML DOM Code<?php

$xmlDoc = new DOMDocument();

$xmlDoc->load("test2.xml");

print $xmlDoc->saveXML();

print "<br/><br/>Alternative - Method 2: <br/><br/>";

$x = $xmlDoc->documentElement;print $x->nodeName.": ";foreach ($x->attributes AS $Attr){ echo $Attr->nodeName." = \"".$Attr->nodeValue."\" ";}

PHP XML DOM CodedisplayChildrenRecursive($x);function displayChildrenRecursive($xmlObj,$depth=0) { foreach ($xmlObj->childNodes AS $child) { if ($child->nodeType==1 ){ echo "<br/>"; echo "-".str_repeat('-',$depth).$child->nodeName.": ";

foreach ($child->attributes AS $attr){ echo str_repeat('',$depth).$attr->nodeName." = \"".

$attr->nodeValue."\" "; } echo "(".$child->textContent.")"; displayChildrenRecursive($child,$depth+1); }}}?>

How Does The Code Work?1. Create a DOMDocument instance and use it

to load an XML file 2. Method 1: The saveXML() function puts the

internal XML document into a string, so we can output it

3. Method 2: - Get the root element name and attributes - Loop recursively through all elements of all

childNodes and output the node (element node and attribute node) names and contents

PHP XML Expat Parser

• The Expat parser is an event-based parser• Event-based parser: Views an XML

document as a series of events, and each event is handled by a sp. function

(Access data faster than tree-based parsers)

• Good for any size of XML files

PHP XML Expat Parser• <from>Jani</from>

• The XML Expat Parser parses the above as a series of 3 events: – Start element: from

– Start CDATA section, value: Jani

– Close element: from

Expat Parser Functions

• There are many: (http://www.php.net/manual/en/book.xml.php)

• xml_parser_create — Create an XML parser

• xml_parser_get_option — Get options from an XML parser

• xml_parser_set_option — Set options in an XML parser

Expat Parser Functions

• xml_set_character_data_handler — Set up character data handler

• xml_set_default_handler — Set up default handler

• xml_set_element_handler — Set up start and end element handlers

• xml_set_processing_instruction_handler — Set up processing instruction (PI) handler

PHP Expat Parser Code

<?phpecho "<pre>"; $file = "test2.xml"; #echo $file."\n"; global $inTag;

$inTag = ""; $xml_parser = xml_parser_create(); xml_parser_set_option($xml_parser,

XML_OPTION_CASE_FOLDING, 0); (---To be continued---)

PHP Expat Parser Codexml_parser_set_option($xml_parser,

XML_OPTION_SKIP_WHITE, 1); xml_set_processing_instruction_handler($xml_parser,

"pi_handler"); xml_set_default_handler($xml_parser,

"parseDEFAULT"); xml_set_element_handler($xml_parser, "startElement",

"endElement"); xml_set_character_data_handler($xml_parser,

"contents"); … (Note: The other code is not displayed here)?php>

How Does The Code Work?1. Initialize the XML parser with the

xml_parser_create() function 2. Create functions for different XML events

with the different event handlers (xml_set_element_handler(), xml_set_character_data_handler(), etc)

3. Parse the XML file with the xml_parse() function

4. In case of an error, add  xml_error_string() function to convert an XML error to a textual description

5. Call the xml_parser_free() function to release the memory

Conclusion

• The Latest PHP 5.3.2 has 3 ways to parse an XML file– SimpleXML– (XML) DOM– XML Expat Parser

• The SimpleXML code is simple and good for most common XML tasks in PHP

• Each PHP XML parser has its own advantages (e.g., SimpleXML is not good for advanced XML with namespaces,while the Expat parser or XML DOM are good for this kind of XML)

DEMOS

• Demo 1 - PHP Processes a simple XML file

(test1.xml) - xml_test1a.php – (SimpleXML)

- xml_test1b.php – (XML DOM)

- xml_test1c.php – (XML Expat Parser)

• Demo 2 - PHP Processes a complex XML (our HWK2 XML) file (test2.xml)

- xml_test2a.php – (SimpleXML)

- xml_test2b.php – (XML DOM)

- xml_test2c.php – (XML Expat Parser)

References1. Official PHP website: http://www.php.net/2. PHP & XML Support History:

http://uk3.php.net/manual/en/history.php.php http://devzone.zend.com/article/1713#Heading13

3. Full Web Building Tutorials: http://www.w3schools.com/4. Parsing XML using SimpleXML: http://debuggable.com/posts/parsing-xml-using-simplexml:480f4dfe-

6a58-4a17-a133-455acbdd56cb5. XML for PHP developers, Part 1: The 15-minute PHP-with-

XML starter http://www.ibm.com/developerworks/library/x-xmlphp1.html6. Beginning XML, 4th Edition. Eds. by David Hunter, Jeff Rafter,

Joe Fawcett, Eric van der Vlist, Danny Ayers, Jon Duckett, Andrew Watt (XMML.com, Strathdon, Scotland), Linda McKinnon (Calgary, Alberta, Canada). Wiley Publishing, Inc, Indianapolis, In, 2007.