PostgresqlSearch.py

# Standard Library
import re

# Third Party Stuff
from django.db import models
from django.contrib.postgres.indexes import GinIndex
from django.contrib.postgres.search import (
    SearchQuery,
    SearchRank,
    SearchVector,
    SearchVectorField,
    TrigramSimilarity,
)
from django.db.models import CharField, F, Func, Value
from django.db.models.signals import post_save
from django.dispatch import receiver


def prepare_search_term(term: str) -> str:
    """Sanitize the input term for a search using postgres to_tsquery.

    Cleans a search string to something acceptable for use with to_tsquery.
    Appends ':*' so that partial matches will also be returned.

    Args:
        term: the search term to be cleaned and prepared

    Returns:
        the prepared search string
    """

    query = re.sub(r"[!\'()|&]", " ", term).strip()
    if query:
        query = re.sub(r"\s+", " & ", query)
        query += ":*"

    return query


class ModelManager(models.Manager):
    search_vectors = SearchVector("label", weight="A", config="english")

    def search(self, text):
        search_query = SearchQuery(
            prepare_search_term(text), config="english", search_type="raw"
        )
        search_rank = SearchRank(F("search_vector"), search_query)
        trigram_similarity = TrigramSimilarity("label", text)
        return (
            self.get_queryset()
            .filter(search_vector=search_query)
            .annotate(rank=search_rank + trigram_similarity)
            .order_by("-rank")
        )
      
      
class MyModel(TimeStampedUUIDModel):
    # Fields
    # =======================
    label = models.CharField(_("label"), max_length=100)
    search_vector = SearchVectorField(null=True)
    
    objects = ModelManager()

    class Meta:
        ordering = ("-created_at",)
        indexes = [GinIndex(fields=["search_vector",])]


# Signals does not get triggered on bulk save or update
@receiver(post_save, sender=MyModel)
def update_search_vector(sender, instance, **kwargs):
    MyModel.objects.filter(pk=instance.pk).update(
        search_vector=SearchVector(
            Func(F("label"), Value("."), Value(" "), function="replace")
        )
    )