django - How do I do a partial field match using Haystack?

Question

I needed a simple search tool for my django-powered web site, so I went with Haystack and Solr. I have set everything up correctly and can find the correct search results when I type in the exact phrase, but I can't get any results when typing in a partial phrase.

For example: "John" returns "John Doe" but "Joh" doesn't return anything.

Model:

class Person(models.Model):
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)

Search Index:

class PersonIndex(SearchIndex):
    text = CharField(document=True, use_template=True)
    first_name = CharField(model_attr = 'first_name')
    last_name = CharField(model_attr = 'last_name')

site.register(Person, PersonIndex)

I'm guessing there's some setting I'm missing that enables partial field matching. I've seen people talking about EdgeNGramFilterFactory() in some forums, and I've Googled it, but I'm not quite sure of its implementation. Plus, I was hoping there was a haystack-specific way of doing it in case I ever switch out the search backend.

Answer 1

You can achieve that behavior by making your index's text field an EdgeNgramField:

class PersonIndex(SearchIndex):
    text = EdgeNgramField(document=True, use_template=True)
    first_name = CharField(model_attr = 'first_name')
    last_name = CharField(model_attr = 'last_name')