Django Postgres database wrapper with `pg_trgm` support.

base.py

from django.db.backends.postgresql_psycopg2 import base


class DatabaseWrapper(base.DatabaseWrapper):
    """ Postgres database backend with support for operations using trigram indexes, inspired by
    https://stackoverflow.com/a/44962928
    
    Put this file in a new module, and point to that module in `settings.DATABASES[<name>]['ENGINE']
    """

    def __init__(self, *args, **kwargs):
        self.operators.update({
            'icontains': 'ILIKE %s',
            'istartswith': 'ILIKE %s',
            'iendswith': 'ILIKE %s',
        })
        self.pattern_ops.update({
            'icontains': "ILIKE '%%' || {} || '%%'",
            'istartswith': "ILIKE {} || '%%'",
            'iendswith': "ILIKE '%%' || {}",
        })
        super(DatabaseWrapper, self).__init__(*args, **kwargs)

    def prepare_database(self):
        super().prepare_database()
        # Check that necessary extensions are installed.
        with self.cursor() as cursor:
            cursor.execute("CREATE EXTENSION IF NOT EXISTS pg_trgm")