PHP with XML
Dequan 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 generalpurpose 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 wellformed 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 Code
For parsing a XML file:
<?php
$xml = simplexml_load_file("test2.xml");
echo $xml->getName() . ": ";
foreach($xml->attributes() as $Attr) {
echo $Attr->getName()."=".$Attr." ";
}
displayChildrenRecursive($xml);
echo "<br />"; (…to be continued…)
PHP SimpleXML Code
function displayChildrenRecursive($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="ISO8859-1"?>
<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." = \"".
$Attr->nodeValue."\" ";}
PHP XML DOM Code
displayChildrenRecursive($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
<?php
echo "<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 Code
xml_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)
References
1.
2.
3.
4.
5.
6.
Official PHP website: http://www.php.net/
PHP & XML Support History:
http://uk3.php.net/manual/en/history.php.php
http://devzone.zend.com/article/1713#Heading13
Full Web Building Tutorials:
http://www.w3schools.com/
Parsing XML using SimpleXML:
http://debuggable.com/posts/parsing-xml-using-simplexml:480f4dfe6a58-4a17-a133-455acbdd56cb
XML for PHP developers, Part 1: The 15-minute PHP-withXML starter
http://www.ibm.com/developerworks/library/x-xmlphp1.html
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.