In a recent blog entry about a fulltext searching solution, Markus Wolff hacked together in a few hours with Zend_Search_Lucene:

While working at some really old code that provided a fulltext search feature, I was at one point incredibly pissed rather unsatisfied due to the fact that said code resisted all attempts to debug it. This lead to the decision to sit down on a rainy weekend to try if I couldn't come up with something more useful, and most importantly, scalable.

His method allowed for separation between the indexing and the main app and how he changes some of his methods when he learned that Solr did something very similar. He also lays out some example XML content and how it's handled in his script (via a SimpleXML object).

A different sort of abstraction layer project has been started up and has already seen a few releases - Forage. As mentioned on Rob Young's blog:

Recently I've been working on a search abstraction library for PHP called Forage. The idea is to bring to search what we've had for relational databases for quite a while, abstraction.

On Friday I put up a preview release with three backends; Solr, Xapian and Zend Search Lucene. At the moment it has the bare minimum of features but there will be more soon. In this post I'm going to talk a little about the motivation for the project and then walk through a short example.

He talks about the need for search abstraction (integration and resilience to change) before getting into an example of some code that grabs the data from an RSS feed, passes it in to the Xapian search engine and stores it before looking it over for thier search terms ("yahoo microsoft").

You can download the library if you'd like to try it out for yourself.