I've been working on Drupal distributed search for a while now, releasing a beta of the OpenSearch Aggregator as well as a release of the OpenSearch feed module. The aggregator has a friendly UI for setting up any number of sources and the feed contains relevance information from the Drupal search system. Results are also cached on the aggregator for performance reasons.

More information about these modules can be found in my earlier blog posts about OpenSearch.

The ultimate goal however is to set up distributed search for a Bryght client between a network of secure Drupal sites. The searches for logged-in users should include content that is visible to them across all the different Drupal sites.

OpenID is the obvious choice as an identity mechanism for the users, but it does not immediately help us with the authentication. I've written a document after some research that details possible approaches and solutions. Because we're talking about frontier technology here, it seemed best to repost it publicly to sollicit feedback from anyone interested. I could certainly use some extra opinions on this, as it is all very new to me.