A Django ORM Expression for Postgres ARRAY literals

django_postgres_arrays.py

from django.contrib.postgres.fields import ArrayField
from django.db.models import Expression, Value
from netfields import InetAddressField


class Array(Expression):
    """A Postgres ARRAY[] expression"""

    def __init__(self, *items, output_field=None):
        if output_field is None:
            raise ValueError('Please specify output_field as the type of the items')

        self.items = tuple(
            Value(item) if isinstance(item, str) else item
            for item in items
        )
        super().__init__(output_field=ArrayField(output_field))

    def __repr__(self):
        return f'<{self.__class__.__name__}: {self}>'

    def __str__(self):
        return f'{{{", ".join(repr(o) for o in self.items)}}}'

    def get_source_expressions(self):
        return self.items

    def set_source_expressions(self, exprs):
        self.items = exprs

    def as_sql(self, compiler, connection):
        expressions = []
        expression_params = []
        for expression in self.items:
            sql, params = compiler.compile(expression)
            expressions.append(sql)
            expression_params.extend(params)

        expression_wrapper = '(ARRAY[%s])'
        sql = connection.ops.combine_expression(',', expressions)
        return expression_wrapper % sql, expression_params


class InetAddressArray(Array):
    def __init__(self, *ips):
        super(InetAddressArray, self).__init__(*ips, output_field=InetAddressField())