I've got a set of documents in a Whoosh index, and I want to provide a search term suggestion feature. So If you type "pop", some suggestions that could come up might be:
I've got the terms that should be coming up as suggestions going into an NGRAMWORDS field in my index, but when I do a query on that field I get autocompleted results rather than the expanded suggestions - so I get documents tagged with "pop culture", but no way to show that term to the user. (For comparison, I'd do this in ElasticSearch using a completion mapping on that field and then use the _suggest endpoint to get the suggestions.)
I can only find examples for autocomplete or spelling correction in the documentation or elsewhere on on the web. Is there any way I can get search term suggestions from my index with Whoosh?
Edit:
expand_prefix was a much-needed pointer in the right direction. I've ended up using a KEYWORD(commas=True, lowercase=True) for my suggest field, and code like this to get suggestions in most-common-first order (expand_prefix and iter_prefix will yield them in alphabetical order):
def get_suggestions(term):
with ix.reader() as r:
suggestions = [(s[0], s[1].doc_frequency()) for s in r.iter_prefix('suggest', term)]
return sorted(suggestions, key=itemgetter(1), reverse=True)
This is not what you are looking for exactly, but probably can help you:
reader = index.reader()
for x in r.expand_prefix('title', 'pop'):
print x
Output example:
pop
popcorn
popular
Update
Another workaround is to build another index with keywords as TEXT only. And play with search language. What I could achieve:
In [12]: list(ix.searcher().search(qp.parse('pop*')))
Out[12]:
[<Hit {'keywords': u'popcorn'}>,
<Hit {'keywords': u'popular'}>,
<Hit {'keywords': u'pope'}>,
<Hit {'keywords': u'Popular Film'}>,
<Hit {'keywords': u'pop culture'}>]