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

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

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

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

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: [ ... ]

Level Seperator: /

Every Level: //

Wildcard: *

Attribute: @

Wildcard-Attribute: @*

Filter or Requirement: [ ... ]

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

starts-with()

contains()

position()

last()

string-length()

substring()

not()

...

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

Some additional functions

document()

format-number()

current()

...

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

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

//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!

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

Thank you.