xml for php developers

XML For PHP Developersby 

Sudheer Satyanarayanahttp://techchorus.net

Bangalore PHP User Group Meetup30 October 2010

Agenda

Quick introduction to XML basicsRecipe 1 - parsing RSS feedRecipe 2 - creating Atom feedRecipe 3 - scraping information from websites using XMLQuestion and answer

At the end of the session, you will be able to start using XML with PHP.

XML Basics

XML document has a tree structure XML documents can be validated using an XML schemaAll major programming languages support reading and writing XML documentsHundreds of technologies are built on top of XMLXHTML is one of the XML markup languages

XML Parsers In PHP

simplexmlDOMSAXXMLReaderXMLWriter

Which Parser To Use

simplexml - really simple XML documentsDOM - heavy liftingSAX - large XML documentsXMLReader - large XML documents

Don't use:string manipulation to create XML documentsregular expressions to parse XML documents

Recipe 1

simplexml usage Programmatically retrieve weather information in your locationUsing Yahoo! Weatherparse RSS feed

RSS - Really Simple Syndication

Sample RSS document    <?xml version="1.0" encoding="ISO-8859-1" ?><rss version="2.0">

<channel><title>My Home Page</title><link>http://www.example.com</link><description>My RSS sample page</description><item><title>RSS Tutorial</title><link>http://www.example.com/rss</link><description>New RSS tutorial</description></item><item><title>XML Tutorial</title><link>http://www.example.com/xml</link><description>New XML tutorial</description></item></channel></rss>

Retrieving weather info from Yahoo!

http://weather.yahooapis.com/forecastrss?w=2442047&u=c w = location, WOEIDu = degrees units (Fahrenheit or Celsius)http://weather.yahooapis.com/forecastrss?w=2295420&u=c

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?><rss version="2.0"xmlns:yweather="http://xml.weather.yahoo.com/ns/rss/1.0"><channel><item><title>Conditions for Bangalore, IN at 8:30 pm IST</title><description><![CDATA[<img src="http://l.yimg.com/a/i/us/we/52/27.gif"/><br /><b>Current Conditions:</b><br />Mostly Cloudy, 24 C<BR /><BR /><b>Forecast:</b><BR />Wed - Partly Cloudy. High: 30 Low: 19<br />Thu - Sunny. High: 33 Low: 20<br /><br />]]></description></item></channel></rss>

Visualization

PHP Code To Parse The Feed<?php

$url = 'http://weather.yahooapis.com/forecastrss?w=2295420&u=c';

$document = file_get_contents($url);

$xml = new SimpleXMLElement($document);

$output = $xml->channel->item->description;

$text_output = strip_tags($output);

echo $text_output;

Output

Current Conditions:Haze, 22 CForecast:Tue - Partly Cloudy. High: 26 Low: 19Wed - Isolated Thunderstorms. High: 27 Low: 19

Full Forecast at Yahoo! Weather(provided by The Weather Channel)

Atom

Atom - key takeaways

Disagreements in RSS community Atom entry documentAtom feed documentAtom Publishing ProtocolUse Atom if you are a feed publisher

Sample Atom Feed<?xml version="1.0"?><feed xmlns="http://www.w3.org/2005/Atom"><link href="http://www.meetup.com/Bangalore-PHP-Users/" rel="self"/><link href="http://www.meetup.com/Bangalore-PHP-Users/feed/atom.html" rel="alternate"/><title>PHP User Group Meet</title><id>http://example.com/my_unique_id.xml</id><subtitle>Bangalore PHP Users</subtitle><updated>2010-10-23T10:30:02Z</updated><entry><link href="http://www.meetup.com/Bangalore-PHP-Users/calendar/15022884/atom.xml" rel="self"/><link href="http://www.meetup.com/Bangalore-PHP-Users/calendar/15022884/atom.html" rel="alternate"/><title>October 2010 Meet</title><summary>Great meetup</summary><id>http://example.com/my_uique_feed_id.xml</id><updated>2010-10-27T10:30:02Z</updated><author><name>Sudheer Satyanarayana</name></author></entry></feed>

Atom Feed Structure

Atom Structure

<link href="..." rel="self"><link href="..." rel="alternate"><title>...</title><id>...</id><summary>...</summary><update>...</updated><author><name>...</name></author>

Recipe 2

Generate an Atom feedPHP DOM

Create An Atom Feed Document

<?php

$doc = DOMDocument::loadXML('<feed/>');

$root = $doc->documentElement;

$root->setAttribute('xmlns','http://www.w3.org/2005/Atom');

Create Link Nodes

$node = $doc->createElement('link');$link = $root->appendChild($node);$link->setAttribute('href', 'http://www.meetup.com/Bangalore-PHP-Users/');$link->setAttribute('rel', 'self');

$node = $doc->createElement('link');$link = $root->appendChild($node);$link->setAttribute('href', 'http://www.meetup.com/Bangalore-PHP-Users/feed/atom.html');$link->setAttribute('rel', 'alternate');

Create Other Nodes

$root->appendChild(new DOMElement('title', 'PHP User Group Meet'));

$root->appendChild(new DOMElement('id', 'http://example.com/my_unique_id.xml'));

$root->appendChild(new DOMElement('subtitle', 'Bangalore PHP Users'));

$root->appendChild(new DOMElement('updated', '2010-10-23T10:30:02Z'));

Create Entry Node$node = $doc->createElement('entry');$entry = $root->appendChild($node);

$node = $doc->createElement('link');$link = $entry->appendChild($node);$link->setAttribute('href', 'http://www.meetup.com/Bangalore-PHP-Users/calendar/15022884/atom.xml');$link->setAttribute('rel', 'self');

$node = $doc->createElement('link');$link = $entry->appendChild($node);$link->setAttribute('href', 'http://www.meetup.com/Bangalore-PHP-Users/calendar/15022884/atom.html');$link->setAttribute('rel', 'alternate');

Create Other Nodes In Entry

$entry->appendChild(new DOMElement('title', 'October 2010 Meet'));$entry->appendChild(new DOMElement('summary', 'Great meetup'));$entry->appendChild(new DOMElement('id', 'http://example.com/my_uique_feed_id.xml'));$entry->appendChild(new DOMElement('updated', '2010-10-27T10:30:02Z'));$node = $doc->createElement('author');$author = $entry->appendChild($node);$author->appendChild(new DOMElement('name', 'Sudheer Satyanarayana'));

Save As XML

$doc->formatOutput = TRUE;

print $doc->saveXML();

Scraping Websites

Grab HTMLTransform to XMLUse XPath to navigate the documentUse accessors to retrieve text content

Recipe 3

Retrieve list of members of Lok Sabha from Government website http://164.100.47.132/LssNew/Members/Alphabaticallist.aspx

<table id="ctl00_ContPlaceHolderMain_Alphabaticallist1_dg1"><tr><td>S.No.</td><td>Name of Member</td><td>Party Name</td><td>Constituency (State)</td></tr><tr><td></td><td><a>Aaroon Rasheed,Shri J.M.</a></td><td>Indian National Congress</td><td>Theni (Tamil Nadu )</td>

</tr><tr><td></td><td><a>Abdul Rahman,Shri</a></td><td>Dravida Munnetra Kazhagam</td><td>Vellore (Tamil Nadu )</td></tr></table>

Building Xpath ExpressionFind the table with the specified ID //table[@id='ctl00_ContPlaceHolderMain_Alphabaticallist1_dg1'] Select all table rows after position 1tr[position()>1] Select table cells with position 2td[position()=2] Select anchor elementaSelect all children that are text nodeschild::text()

Final Xpath Expression

//table[@id='ctl00_ContPlaceHolderMain_Alphabaticallist1_dg1']/tr[position()>1]/td[position()=2]/a/child::text()

PHP Script<?php$html = file_get_contents('http://164.100.47.132/LssNew/Members/Alphabaticallist.aspx');$doc = new DOMDocument();$doc->loadHtml($html);

$domxpath = new DOMXPath($doc);$xpath_expression = "//table[@id='ctl00_ContPlaceHolderMain_Alphabaticallist1_dg1']/tr[position()

>1]/td[position()=2]/a/child::text()";$result = $domxpath->evaluate($xpath_expression);

echo "Total number of memembers of Lok Sabha " . $result->length;

foreach ($result as $r) {

echo "\n" . $r->nodeValue;

}

QOTD

Retrieves quote of the day from Wikiquotes.orgCreates a feedAlso sends SMS to subscribers

http://qotd.techchorus.net http://labs.google.co.in/smschannels/channel/WikiQuoteOfTheDay

Where To Go From Here?

Start using XML right awayNow you know how to parse and create feedsLearn more XML technologies Read the specifications Scrape websitesImagination is your limitBuild the next big thing since sliced bread!

ResourcesDownload files shown in this presentation -

http://techchorus.net/downloads/xml-for-php-developers/xml-for-php-developers.tar.gz http://techchorus.net/downloads/xml-for-php-developers/xml-for-php-developers.zip

PHP Manual - http://in3.php.net/manual/en/refs.xml.phpTech Chorus - http://techchorus.netW3Schools - http://www.w3schools.com/xml/default.aspBook - Pro PHP And XML Web Services by Robert Richards. Review - http://techchorus.net/pro-php-xml-and-web-services-book-reviewMore useful links - http://xml.farsquare.com/

Questions?

Thank You

The slides will be available at SlideSharehttp://www.slideshare.net/bngsudheer

My Twitter handle: @bngsudheer

Blog: http://techchorus.net

Business: http://binaryvibes.co.in

E-mail: sudheer @ above business URL

License

XML For PHP Developers by Sudheer Satyanarayana is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 2.5 India License . Based on a work at techchorus.net . Permissions beyond the scope of this license may be available at http://techchorus.net .