2009 05 20 Phptek 2009 Xpath

Understanding XPath Arne Blankerts at php|tek 2009, Chicago, USA May 20 th 2009

Who we are Premium PHP Consulting & Training. Worldwide. Arne Blankerts Sebastian Bergmann Stefan Priebsch

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]
@id
/root//node/@name
/root/element[@name = 'php']/@*.
./some/*[@class='tek']/@id

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 ;-)

Thank you.

2009 05 20 Phptek 2009 Xpath

by Arne Blankerts on May 20, 2009

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2009 05 20 Phptek 2009 Xpath — Presentation Transcript