Calais is a free web service from Clearforest, a Reuters company, that can perform semantic analysis on any English text. It uses natural language processing to extract concepts and relationships from the text. It’s been around for a few months, but there’s been very little developer activity around it, and even fewer completed applications using the technology.
Not finding any other work to build on, I wrote my own PHP class for extracting tags from content with Open Calais’ API. You can get the source and read more here. This class takes a block of text or HTML, sends it to Open Calais or parsing, and extracts all of the entities (things like peoples’ names, companies, technologies, etc.). It returns a multidimensional array organized by entity type.
There’s more Open Calais can do, but I hope this class contributes something to those PHP developers that’d like to start using it but had no place to start with the lightweight documentation and eerily quiet official forums. I plan on putting this class to work as an auto-tagging plugin for WordPress posts. I still need some time to figure out how to integrate that into the new authoring interface of WP 2.5, which this blog is now running on.
Alister Cameron // Blogologist
April 21st, 2008
Dan,
BRILLIANT!
I have been waiting for someone to do this.
Thanks SO much.
Whatever else you can do with it… go for it!
I think OC is one of the new gems of the Semantic Web and I can see it being so useful to Wordpress in various ways.
Thanks for getting the ball rolling
-A
PS. Did you win the money?!
Dan
April 21st, 2008
Glad you like it! No, I didn’t enter the bounty program, so I wrote these plugins for free.
Clara
June 8th, 2008
I’m using WPMU
I got message error like it..
Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or ‘}’ in /home/XXX/public_html/wp-content/plugins/calais-auto-tagger/opencalais.php on line 17
Hope you can make this plugin compatible with WPmu.
Thx
Sam
February 25th, 2009
Hi Dan,
we are using your opencalais PHP code.
OpenCalais have upgraded their service and the code requires a little modification. We are initially just changing the URL and will carry out some investigation into the new categories.
I just thought I would let you know.
Cheers,
Sam.