Filtering on index.RelatedFields

[kaedroho]

For Example, say we have the following models:

class Author(models.Model):
    name = models.CharField()
    birth_date = models.DateField()
    ...


class Book(index.Indexed, models.Model):
    title = models.CharField()
    author = models.ForeignKey(Author)
    ...

    search_fields = [
        index.SearchField("title"),
        index.RelatedFields("author", [
            index.FilterField("birth_date")
        ]),
    ]

The following query won't work, because author__birth_date can't be used:

Book.objects.filter(author__birth_date__lt=date(1, 1, 1950)).search("A search query")

This is currently unimplemented because of the way Django stores related filter lookups on QuerySets is quite difficult to reverse.

[Prill]

What I would find useful is the ability to get a regular Django queryset that has a filter for pk__in=<PKs of matched products>.

Right now you can do this with something like .filter(pk__in=(e.pk for e in results)) but this causes the ElasticSearch backend to instantiate each product resulting in unnecessary DB queries for the other fields (one for each page of data).

Is there a way around this?

[gasman]

Working on this. From initial investigations it looks like the database backends might Just Work once we've fixed the initial problem with validating that the field is present in search_fields (which fails because it's checking the list for the base model instead of the related one). Elasticsearch/Opensearch will need more work to translate those relations to the document structure, of course.