QueryPath, Mash-ups, and Web Services

QueryPath For Web Services and Mash-ups

• Who created it? • What does it do? • Where is it being used? • Why use it? • How is it used?

Matt Butcher Maintainer of QueryPath and the Drupal QueryPath module http://technosophos.com http://twitter.com/technosophos

2009 2004

What is QueryPath? QueryPath is a library for working with HTML and XML in PHP. It is like jQuery for the Server.

Why Another XML Library?

The Task Find all <a></a> tags who have the ancestor <div></div>

The DOM API • At least seventeen classes, each with dozens of methods. • Complex data structure. • Checkered history in PHP. • VERY powerful.

SimpleXML • One class, about a dozen functions and methods. • Turns XML into basic objects. • Makes easy stuff easy, and makes everything else insanely hard. Same size as DOM Example

SAX / Expat Same size, fewer features • Event based. • Write your own parser handler. • One per XML format. • Only reliable “legacy” library.

QueryPath • Compact library. • Functions are short and mnemonic. [This space intentionally left blank ] • The power of DOM, but simpler than SimpleXML • (Shhh... don’t tell, but it’s built on the DOM.)

Use it to... • Import HTML files • Create HTML on the fly • Read XML files • Retrieve database content and insert it • Work with remote web into XML or HTML services • Examine RDFa data • Manipulate SVG images inside HTML or XHTML • Retrieve RSS and Atom • Run SPARQL queries feed data and retrieve SemWeb content

Where is it Used?

Importing Content • 6,000+ existing documents • Fragments of HTML 2, 3, and 4 • Much of it non-standard • Imported into Drupal using BatchAPI, Tidy, and QueryPath

Querying Semantic Information • Use the OpenAmplify web service • Submit node content • Use results to enrich page • Build a supermashup (seven web services) http://www.youtube.com/watch?v=GBBKPIva1tM

Gateway to Web Services • 100’s of Gigabytes of data • Stored in an external Digital Asset Management tool • XML gateway • QueryPath integrates Drupal with the DAM

Semantic Network • DBPedia is semantic equivalent of Wikipedia • Query with SPARQL • Return semantically oriented XML content • QueryPath can query and make use of the results

Twitter Mash-up • Retrieve latest posts from Twitter • Submit them to OpenAmplify for analysis • Provide “ratings” and sentiment information • Not in Drupal http://tweetypants.com

Frameweld Framework • Frameweld uses QueryPath as part of their proprietary framework • Clean separation of presentation and other logic • QueryPath translates data objects into HTML Frameweld contributes back to QueryPath

Why Use It?

Shorten Difﬁcult Tasks <?php require 'QueryPath/QueryPath.php'; $odt = 'zip://o.odt#content.xml'; foreach(qp($odt, 'text|h') as $i) { print $i->text() . "n"; } (Prints an outline from an ODT document)

Twitter Search Ten Lines of Code

How is it Used?

A Closer Look ‣Object-oriented ‣Operates on ﬁles, strings, or streams ‣Uses CSS 3 Selectors ‣Has dozens of methods

The Features • Query a document • Access remote data • With XPath • Extensions for... • CSS selectors • XSLT, XSD, PI • Move around inside the • SQL database access document • Templates • Modify the document • Access local ﬁles

Traversing an HTML or XML Document There are over a dozen functions for traversing a document. These are similar to jQuery’s traversal functions.

Manipulating a Document • Get and set text, elements, attributes, etc. • Move, clone, delete. • Build arbitrary XML or HTML.

In Drupal... • Install the QueryPath module • Begin using QueryPath in your modules

Outside of Drupal • Go to QueryPath.org • Download QueryPath • Use it in your applications

Learn More • IBM DeveloperWorks published an introduction to QueryPath: http://is.gd/2wHPA • The full API docs are available at http://api.querypath.org • Learn more about Drupal modules at http://dupal.org/project/querypath

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QueryPath, Mash-ups, and Web Services

by Matt Butcher on Oct 22, 2009

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QueryPath, Mash-ups, and Web Services — Presentation Transcript