search extension for Radiant CMS on Heroku?

Can anyone recommend a good Radiant CMS search extension with decent documentation that works on Heroku? The only one I've found that seems to work is the Google Custom Search one but it is not extendable a开发者_开发技巧nd has ads.

Thanks

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Have you looked at spinx_search for radiant?

https://github.com/radiant/radiant/wiki/Search-Extension