Xpath with PHP
Arne Blankerts at FrOSCon 2009
August 22nd 2009
Copyright © 2009 thePHP.cc, Germany

XPath?
 An XML Query Language
 Often considered the SQL for XML
 XML seen as a directory structure
 Allows for easy and flexible finding of nodes
 Supports very complex queries with yet an
easy to read syntax
 Version 2 just recently standardized
 LibXML 2 so far only supports version 1
 Bug Rob Richards to add version 2 ;-P

XPath?
 XSL(T)
 XML Stylesheet Language
 Used for (T)ransformations of XML dialects
 Available through libXSL & ext/xsl in php
 DOM Standard
 DOMXPath Object within PHP (ext/dom)
 Native API in Gecko based browers
 Selenium Testing
 Specify elements for the tests

XPath and DOM
 Two ways to query
 A query returns a Nodelist
 Nodelists contain only references to DomNodes
 A query can also return a direct value
 Namespace aware
 Must use prefixes – all the time
 Do not mix with DOM Level 1 Methods

XPath and PHP
 DOM
 DOMXPath Object
 Used in conjunction with DOMDocument
 Nodelists contain references to DOMNodes
 SimpleXML
 Direct query possible, no seperate Objects
 Array of references to SimpleXML-Objects

XPath – The basic syntax
 Level Seperator: /
 Every Level: //
 Wildcard: *
 Attribute: @
 Wildcard-Attribute: @*
 Filter or Requirement: [ ... ]

XPath functions – a selection
 starts-with()
 contains()
 position()
 last()
 string-length()
 substring()
 not()
 ...

XPath and XSL(T)
 Some additional functions
 document()
 format-number()
 current()
 ...

XPath, XSL and PHP
 PHP Callbacks possible
 php:function(....)
 EXSLT-Functions
 Date & Time handling
 Custom functions
 ...

XPath Samples
 //node
 /root/element
 /root/element[1]
 Xpath starts counting with 1 (except for IE 6)
 @id
 /root//node/@name
 /root/element[@name = 'php']/@*
 ./some/*[@class='tek']/@id
 //php:node/demo:element[test]

XPath in the real world.
Aka let's play
Live Demo ;-)

Selenium
 GUI Testing framework
 For webbased content and applications
 Selenium IDE
 Firefox Extension for easy test writing
 Selenium RC (remote control)
 Server process to automate testing
 Controls Gecko, Webkit and even IE
 Supported by PHPUnit!

Selenium IDE
Live Demo ;-)

Q & A
Copyright © 2009 thePHP.cc, Germany

Thank you.
Copyright © 2009 thePHP.cc, Germany