RDF and SPARQL for PHP Developers (at New York Semantic Web Meetup)

RDF and SPARQL for PHP Developers – NY Semantic Web Meetup - May 21, 2009

RDF and SPARQL for PHP
Developers

Benjamin Nowack
bnode.org / semsol.com


Two Perspectives

(1) How can PHP developers benefit
from the emerging Semantic Web
(technologies)?
(2) How can Semantic Web projects
benefit from PHP (developers)?


Scripting Languages
● Templating
● Request handlers
● Controllers
● Framework extensions
● Glue code
● Prototyping


PHP/Ruby/... Developers
● talk with designers and UX teams
● understand data models
● talk with (or are) back-end
developers
● know agency processes
● are efficient and cost-effective


Scripting language developers
have strong and multidisciplinary
front-end skills that lack in the
current SemWeb landscape!


Win-Win
● demand will grow, good investment
● more interesting, possibly better
paid projects
●
improved productivity
●
more (usable) semantic web apps
● reduced time to market


But there is more to the Semantic
Web than „just“ direct business
opportunities...


Two Other SemWeb Perspectives

(1) A Web of machine-processable data
(2) A collection of powerful technologies


Technical Issues
● Templating/UI: back-end-dependent
● Request handlers: custom code and APIs
● Controllers: local, fixed models only
● Framework extensions: no standards
● Glue code: many one-off conversions
● Prototypes: schema changes are painful


Semantic Web technologies address
these technical limitations and
related productivity issues.


SemWeb for Web Development
● a simple, unifying data model (RDF)
● standardized data exchange formats
● lossless data portability
● a powerful, simple data API (SPARQL)
● re-mixable schemas (RDFS/OWL)
● automated data processing


Technical Opportunities
● Templating/UI: back-end independence
● Request handlers: reusable code / APIs
● Controllers: distributed models
● Framework extensions: standards, reuse
● Glue code: less conversion code
● Prototypes: less painful schema changes


However...


The ROI has to justify the initial
friction loss!


When SemWeb Tech (or not)?
● My projects integrate data from the Web
● (Semantic) web standards and openness
matter to me and/or my clients
● I often work with non-stable schemas
● I can afford betting on an evolving
technology stack


Re Friction Loss
● There is almost no developer-oriented
learning material
● Some things work differently in RDF
(validation, data quality, API control, ...)
●
Identifying and getting used to needed
specs and vocabularies takes time
●
All toolkits have non-standard extensions


ARC RDF Classes: Motivation
● something light-weight and optimized
for PHP environments (and mindsets)
● tools that are easy to combine with
existing software
● support for Web 2.0 data formats, too
(microformats, RSS2, Atom, JSON)


Pure-PHP RDF Software
● RAP (RDF toolkit)
● pOWL (CMS, app framework)
● ARC (RDF toolkit)
● OntoWiki / Erfurt (CMS, API)
●
Drupal (soon w/ RDF in core)
● Trice (CMS, app framework)


More PHP(ish) RDF Software
● Redland (RDF toolkit w/ PHP bindings)
● Semantic MediaWiki (PHP-based)
● Talis platform (has lots of PHP tools)
● Virtuoso (PHP interpreter built in)
● paget (Linked Data publishing)
● Loomp (Semantic publishing)


ARC
● A pick-what-you-need RDF toolkit
● HTTP reading/posting
● Parsing (RDF formats, Atom, RSS, MFs)
● Serializing (XML, JSON, Turtle)
● Storage & Querying (local or remote)
● SPARQL Scripting


Trice
● A basic app framework on top of ARC
● Working with RDF stores made easy
● Path-based request handlers
● Forms with automatic RDF generation
● Sessions (OpenID or local user:pass)
● Themes (per request handler)


ARC / Trice
Software requirements:
ARC: Web server, PHP, MySQL (storage)
Trice: ARC, mod_rewrite, .htaccess

Setup:
ARC: upload
Trice: sys.php / upload / file cache /
first request creates RDF store(s)
and admin account


Examples & Demos
● Accelerated prototyping (Data First)
● Less painful schema changes (RDF)
● Reusable template sections (URIs)
● The page is a (standardized) API (RDFa)
● Less custom glue code (RDF formats)
●
A powerful API for free (SPARQL)


Examples & Demos (ctd.)
● Lossless Backup/Deploy (UghRIs!)
● Simple remote data integration (LOD)
● Remote model access (LOD + SPARQL)
● Increasing data value (RDFa <=> LOAD)
● Inference scripts (Sparqlets)
●
Putting it all together (Paggr/ConfX)


Some Lessons Learned (the hard way)


• Start small.


• Focus on the use cases at hand.
(The „potential“ ones will come
early enough.)


• Partition data when possible.


• Resist the „I could automate this
even further, right now“ reflex.


• Respect the core standards, but
expect the need for custom
solutions here and there (and let
the community know).


• Don't pick more from the SemWeb
Menu than you can consume.


Thank You

● http://arc.semsol.org/
● http://trice.semsol.org/ (soon)
● http://semsol.com/
● http://bnode.org/

RDF and SPARQL for PHP Developers (at New York Semantic Web Meetup)

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