I'm creating a full text search engine for a series of approximately 10 public domain books. The corpus will rarely be updated. Proximity search will be the core feature, e.g. locating "hello" within 5 words of "world".
I'm looking at both Haystack for Django/Python and Ruby solutions. I'm aware of: Solr, Elasticsearch, Whoosh, Xapian, and Sphinx.
With such a small corpus I'm focused on ease of implementation, and right now I'm leaning toward Whoosh (pure Python) or Sphinx (with Haystack or maybe Ruby on Rails). Thoughts?