Adopt Search API as the standard search solution in Debut

Problem/Motivation

The Debut features spec requires formally adopting standard solutions:

Before introducing a new Debut feature that introduces a dependency that could be considered as a new standard solution, an issue must be posted on the Debut project proposing the new standard solution with justification.

#1289696: Candidate Debut feature: Debut Search, built on Search API introduces Search API as such a dependency.

Proposed resolution

Drupal core search is limited in many ways: performance issues, lack of flexibility, limited Views integration, no native support for faceted search, etc. However, solutions built on a particular search index backend server (e.g., http://drupal.org/project/apachesolr) are also limited in that they cannot be used unless that backend is in place.

The Search API, http://drupal.org/project/search_api, provides a powerful and flexible toolset. In particular, it will allow building a common framework that can be used in low-resource cases with the Drupal database as a backend but will also support more powerful solutions like solr.

Potential issues to consider include:

• Stability: While the base module appears to be fairly stable, the database backend has known issues and is not a focus for the maintainer. This situation implies some risk. However, on initial testing, it appears to be basically functional.
• Longevity: It's not clear at this point the extent to which Search API will gain traction and become an enduring solution. However, there is no other solution that both meets the base Debut criteria and has a more promising future.